Sustainable cropping systems for dairy farmers in the Northeast, II

2015 Annual Report for LNE13-329

Project Type: Research and Education
Funds awarded in 2013: $400,000.00
Projected End Date: 12/31/2016
Region: Northeast
State: Pennsylvania
Project Leader:
Dr. Heather Karsten
The Pennsylvania State University

Sustainable cropping systems for dairy farmers in the Northeast, II


In Pennsylvania, we are evaluating two diverse, six-year no-till crop rotations designed to produce all the feed, forage and some tractor fuel for a 65 cow, 240 acre dairy farm. In each 6 year crop rotation we compared enhanced conservation practices for manure or pest management to typical no-till PA cropping practices. In the manure rotation we compared manure injection to surface application. In the pest rotation, we compared a combination of reduced-herbicide weed control practices to standard herbicides, and used integrated pest management to manage slug and insect pests. We also included a typical no-till, corn-soy rotation with pre-emptive insect control practices to help assess efficacy of IPM compared to this insurance-based management of insect pests, not to produce feed for the dairy farm. We initiated the crop rotations in 2010 on 14 acres with farm-scale equipment; all crop entries were planted each year in a split-plot experimental design with four replications. Using the crop yield and quality results of each year and a dairy nutrition computer model, we  simulated milk production and compared the whole farm performance of two cropping scenarios (the two, 6-year enhanced conservation cropping systems compared to the two, 6-year typical no-till cropping systems). Weather conditions and feed and milk prices varied over the six years, enabling us to evaluate and modify the cropping systems to sustain the herd in years with weather limitations and assess economic viability over time.

The cropping scenarios produced the majority of the dairy feed and forage, and were profitable. Manure injection conserved more nutrients, required on average 33% less inorganic nitrogen fertilizer and maintained similar crop yields. The reduced herbicide practices controlled weeds and maintained crop yield and quality similarly to the standard herbicide system in most crops in most years. Compared to the corn-soy rotation, IPM was successful in maintaining yield while minimizing costs associated with insect pest management. Notably, in the diverse rotations arthropod predator populations were larger and more active, killing more prey and limiting plant damage. Soil quality indicators were higher or similar in the diverse rotations compared to the corn–soybean rotation. Having completed one phase of the six-year rotations, we can now evaluate how the agroecosystems have changed and performed over additional years of weather, pest, and market dynamics. We will continue to test our original hypotheses, and some new hypotheses and minor modifications designed to improve the performance of the cropping systems. To promote adoption of the enhanced conservation cropping systems, we will also conduct some research on commercial farms and develop extension education activities around five dairy cropping system strategies that we have identified as most likely to be adopted.

Objectives/Performance Targets

There are two major objectives of this project: i. to identify how to enhance the sustainability of dairy cropping systems and dairy farms in the Northeast by integrating best management practices with innovative technologies, ii. to promote adoption of the cropping system practices by farmers.


Experimental design and its implementation

We initiated two diverse, 6-year dairy crop rotations using farm-scale equipment at 1/20th scale of 240 acres on 12 acres of Penn State’s Agronomy Research Farm near University Park, PA. Cropping system strategies include no till, manure injection, cover crops, a cover crop roller, perennial legumes, green manure crops, winter canola and a straight vegetable oil tractor. Within each crop rotation we are evaluating innovative management strategies to address key issues: i. manure management in no-till cropping systems with shallow-disk manure injection; and ii. Reducing herbicide and insecticide use with cultural and mechanical integrated weed management practices, and biological and integrated pest management practices for insect and slug management. To examine the effect of diverse rotations managed with IPM practices on insect pests and beneficial insect populations, a corn-soybean grain rotation was also included for comparison purposes integrated into the experimental site on an additional 2 acres (see 2014- 2015 Cropping Schematic). In the corn-soybean rotation, we are also comparing the manure management strategies (injected or broadcast manure) and inorganic fertilizer. In addition, our USDA ARS team established twelve lysimeter plots (50 x 90 ft.) on a slope to compare total nutrient losses and crop uptake between manure and crop management strategies on an additional 1.3 acres.

 The experiment is a nested split-split plot, full crop entry design. All crop phases of each rotation are planted each year on 0.25 acre plots that are replicated four times (12 crop entries for the 2 year rotations, 2 crop entries for the corn-soybean rotation X 4 replications = 56 plots). Each crop entry is the main plot (120 ft. x 90 ft.) that is divided in half (60 ft by 90 ft) to compare the management strategies over time (ex. inject manure or broadcast manure).  To compare two green manure crops (red clover vs. crimson clover), the manure rotation has nested split-split plots (30 x 90 ft.) within both manure management strategies. In the pest rotation there are nested split-split plots (30 x 90 ft.) within the reduced herbicide treatment in the soybean and corn crops that compare two post-planting weed control strategies (high-residue cultivator or post-emergent herbicide). Since the cultivator requires wider row spacing (30 inch, 76 cm) than is typical for no-till soybeans, we have also included split-split plots in the soybean standard herbicide treatment to compare the soybean row spacing of 30 inch (76 cm) to a more typical 15 inch (38 cm) row spacing. We are evaluating multiple performance indicators: crop yield and quality, soil health, nutrient conservation, greenhouse gas emissions, weed and insect populations; energy use and production, and farm profitability. We continue to collect three subsamples for forage or feed for quality analysis from each of our main management treatments in the MANURE and PEST rotations at every crop harvest in the NESARE Dairy Cropping Systems Trial.

 We simulate making corn and alfalfa-grass silage and soybean roasting in the laboratory prior to submitting them to Dairy One for forage quality analysis. The dairy scientist, Virginia Ishler uses the quality and yield data to develop rations for the virtual dairy herd, and a dairy nutrition model to simulate a dairy herd’s milk production under the two different cropping system scenarios: the enhanced conservation cropping systems (the inject manure and reduced herbicide managements) compared to the more typical (broadcast manure and standard herbicide managements).


Weather conditions over the past six years provided a range of opportunities to assess cropping system performance. Rainy fall (2011, 2012) and spring (2011, 2012) conditions had high slug density activity and years with dry mid-summer weather (2011, 2012) had reduced corn and perennial forage crop production (Figure 1). With unusually warm early spring temperatures in 2012 and 2015 (Figure 2), canola flowered early and during the unusually cold winter with limited snow cover of 2014, winter canola and crimson clover died (Figure 2). In 2014 and 2015, precipitation totaled 25.9 and 27.8 inches in respectively, however, May and August 2015 were drier than 2014 (Figure 3). 

Manure Rotation: Yields

Crop yields were collected for each crop entry point in the MANURE rotation in 2015; data was analyzed with a split-plot, mixed ANOVA model using PROC MIXED of SAS for all crops that received manure in the rotation. When significant, interactive effects were found, the SLICE function was used to determine statistical significance. Similar to the results found in 2013 and 2014, crop yields were similar between the broadcast and injected manure treatments (Table 1). Crop × manure management interaction effect on crops yield was significant. Despite no significant effect of manure application on crops yield, corn silage after interseeded cover crops tended to be higher in plots where manure was broadcasted (BM) compared to the manure injection treatment (IM) (Table 1). Probably, side-dress application of nitrogen fertilizer applied to the BM treatment and not the IM treatment explains this trend (See appendix).

Lysimeter Plots: Improving Nitrogen Retention under Alternative Manure Management Strategies

The lysimeter team has continued monitoring nutrient surface and subsurface and gaseous N losses from the lysimeter plots that can contribute to water pollution. They are working towards developing a N balance for the broadcast and injected manure treatments.

Nitrate loss- over land-subsurface

Quantification of nitrate losses in overland and subsurface flow from lysimeter plots indicated no significant difference (P<0.1) in losses between shallow disk injection of manure and unincorporated, broadcast applications (Figure 4). Low loads with surface application are typical and expected. Limited previous research indicated a possible increase in subsurface nitrate losses with injection, so the lack of differences between application methods was a positive finding.

Nitrogen Balance for Injected Dairy Manure

Nitrogen fate was compared between shallow disk injection and unincorporated, broadcast application of dairy manure in 2012 and 2013 using plot scale lysimeters. Losses to air and water, as well as crop N uptake were monitored. Silage corn with a winter cover crop was grown each year, using no-till practices, to allow for annual or biannual manure application. Plots were underlain by shallow bedrock, which created a perched water table at the site. Subsurface tiling at each plot allowed for the collection of subsurface water flow and the quantification of leached N. Plots perimeters were also bermed to allow isolation and collection of overland flow from each plot. Nitrogen losses to the atmosphere were assessed by measuring ammonia volatilization and nitrous oxide emission. Corn silage biomass production and N content were quantified to estimate crop N uptake. Additionally, pre-side dress nitrate tests (PSNT) and late season stalk nitrate tests were conducted as indicators of the status of N availability to the crop. Total manure N applications ranged from 172 to 209 kg/ha. Ammonia volatilization was the N fate most impacted by manure injection. Approximately 30% of the applied manure-N was lost as ammonia with unincorporated, broadcast applications in the spring, but losses were reduced by approximately 90% with shallow disk injection. Overland flow accounted for a very small portion of the N losses (<0.2%) and was not impacted by manure application method. Leaching losses were also similar between treatments and accounted for 1-4% of the applied N.
Corn silage biomass production was similar with the two manure application methods (15-20 Mg/ha), but corn N uptake tended to be greater with injection. Crop uptake accounted for 84 and 73% of applied manure N with injection and broadcast application, respectively, in 2012 and 65 and 43% of applied manure N with injection and broadcast application, respectively, in Late season stalk nitrate tests indicated a better plant N status when manure was injected, and PSNT data suggested greater mid-season N availability. Given the lack of yield response despite greater plant N uptake, it appears that crop yield in this system was limited by factors other than N availability. However, the data suggested that yields at this location could be maintained with less N input when manure is injected. While side-dress N applications were not made on these lysimeter plots, PSNTs indicated that corn in injected plots typically would not have benefitted from mid-season side applications of N while broadcast applied plots would have (similar trend seen with the plots in the larger crop rotation study). A downside of injection was a 2 to 3 fold increase in nitrous oxide emission. The total quantity of N emitted as nitrous oxide does not have a large agronomic impact (2 to 4% of total applied N). However elevated nitrous oxide emission with injection has implications for climate change, since N2O is a potent greenhouse gas.

Phosphorus concentration and loss from the field lysimeter plots

Runoff monitoring results from the field lysimeters highlight the benefit of manure injection with regard to mitigating phosphorus (P) losses in overland flow (Figure 5). Overall, losses of total P in overland flow averaged 0.6 kg /ha/yr with injection whereas they averaged 1.19 kg /ha/yr with conventional broadcast application. Very large spikes in total P concentration (mg/L) in overland flow were observed with surface application of manure in the spring of 2012 (12.3 mg/L) and fall of 2014 (19.3 mg/L), highlighting the acute wash off of manure P. During other periods, the concentrations were always slightly elevated with broadcast application (Figure 6). When losses of P in overland flow were expressed on a yield basis (kg/ha), the interactive effects of injection on availability of manure P and on hydrology (the ridges from injection often help to break up flow pathways and reduce runoff) were even more striking. This study also suggests that manure injection may affect subsurface losses of P in shallow groundwater, although our findings are inconclusive. While this pathway of P loss is typically not considered to be important in upland environments, the fact the location of the site is in a karst landscape offers reason to consider subsurface P transport as a potential pathway for P loss. Specifically, concentrations of P in subsurface flow were often elevated with broadcast application (Figure 6).Effects on subsurface P yields (kg/ha) were not as obvious, although there was one event in which the effect was profound (0.46 Kg/Ha). Given the emerging importance of subsurface P in such settings as the Western Lake Erie Basin and the coastal plain of the Chesapeake Bay Watershed, this potential benefit of manure injection could be a key finding that would influence the promotion of manure injection.

The impact of nitrogen source on soil nitrous oxide emissions in sustainable cover-crop based rotations

The use of large amount of nitrogen (N) inputs in intensive agricultural systems has led to important environmental impacts. Nitrous oxide (N2O) is a potent greenhouse gas released from agricultural soils as a by-product of the microbial process of nitrification and denitrification. Research has shown that cover crops can enhance nitrous oxide (N2O) emissions, but the magnitude of increase depends on the quantity and quality of the nitrogen (N) input (Gomez et al. 2009). Also, the timing of N fertilizer application and nitrate concentration in the soil effects N2O emissions (Mitchell et al. 2013).  

Soil N2O emissions were evaluated in 2015 from soils planted to corn in 3 blocks of the

experiment with:

1) Three different previous crops including:

i) Alfalfa (Medicago sativa ) and orchardgrass (Dactylis glomerata L.) with spring broadcasted manure

ii) Crimsom clover (Trifolium incarnatum) with spring broadcasted manure and

iii) Soybean (Glycine max (L.) Merr.) with spring broadcast manure.

2) Three different N application strategies in a soy-corn rotation consisting of:

i) Injected manure with a shallow disk injector: single application pre-planting,

ii) Unincorporated, broadcast manure and inorganic fertilizer: manure before planting and inorganic N side dressed at V6

iii) Inorganic nitrogen fertilization: single application at V6 growth stage.

Nitrous oxide fluxes were measured with vented static chambers (78.5 cm x 40.5 cm) from each treatment plot during the corn growing season. Chamber frames were placed perpendicularly across two corn rows in two locations in each plot, for a total of 36 frames (6 treatments x 3 blocks x 2 repetitions). The chamber design followed USDA-ARS GRACEnet Project Protocols Chapter 3, Chamber-Based Trace Gas Flux Measurements (Parkin et al., 2011). The sampling was two times a week during the first 61 days after cover crops were terminated and manure was applied. In the following period, sampling had intervals from 7 to 31 days. Measurements were taken prior to and during the period of anticipated N2O fluxes to capture profile of gas emissions during entire growing season. Fluxes were measured between 9:00 to 12:00 h to minimize diurnal variation in the flux pattern. Samples were collected at 0, 10, 20 and 30 minutes and analyzed with a gas chromatography. The rate of N2O emissions (g NN2O/ ha/d) was calculated from the four data points using linear regression. Cumulative N2O emissions were calculated by linear interpolation. Soil moisture and soil temperature were measured at the soil surface (0-10 cm) every time gas samples were taken. Soil samples (3 cores of 2cm diameter/plot) were taken once a week from the top layer (0-5cm) and analyzed for ammonium (NH4+) and nitrate (NO3). The method employed in this study was: five grams of soil were combined with 25 mL of 2 mol L–1 KCl (2N KCL, 5:1) and shaken on an oscillating shaker for 1 hour. Extracts were analyzed for NH4–N and NO3–N concentration on a Lachat flow injection autoanalyzer (Hach Company) in the Agricultural Research Service from the USDA. Data were analyzed in SAS with PROC mixed using the repeated measures procedure. The previous crop was a fixed effect and blocks were considered random.  

N2O Emission Research Conclusions

In 2015, elevated N2O emissions were observed from legume treatments about 15 days after the previous crops were terminated and spring manure was applied. High legume biomass, manure N inputs (Figure 7) and weather conditions favored denitrification. In alfalfa + orchard grass and crimson clover treatments daily mean fluxes varied from 2.26 to 50.86 kg N-N2O /ha/day and 1.17 to 51.16 kg N-N2O /ha/day, respectively. By 45 days after the cover crops were terminated and manure was applied, the emissions were lower, varying in the alfalfa + orchardgrass treatment from -0.01 to 7.26 kg N-N2O /ha/day and in the crimson clover from 0.09 to 6.35 kg N-N2O /ha/day (Figure 7). Nitrate (NO3) and NH4+ soil levels increased slowly in early spring after manure was applied and cover crops were terminated (Figure 8), likely due to slow N mineralization. Later in the season when corn was side-dressed, the inorganic N levels rapidly increased. The higher emissions of N2O in the corn-soybean rotation happened after manure and fertilizer were applied, contributing to 50.7 % and 28.7 %, respectively, to the 1326 kg N-N2O /ha cumulative emissions (Figure 7). Among the crop rotations, the corn-soybean had the highest cumulative emission (Figure 9). However, N2O emission in response to side-dress N application in the corn following soybean was larger than previous years due to very wet soils in June, 2015. 
When comparing different N application strategies in the corn-soy rotation, the injected manure treatment had the highest cumulative emission (2.192 kg N-N2O /ha) (Figures 10, 11), likely because manure injection created a 10 cm deep band of concentrated N, high moisture, and organic matter. Cumulative emissions were lower in the treatment in which N fertilizer was applied only at V6 growth stage. Pre-plant manure application had high potential for N2O emissions, likely because corn was not yet actively taking up the N. Also, cover crop residue input did not increase N2O emissions relative to the soybean treatment since additional side-dress inorganic N fertilizer was not needed. When comparing different methods of N application in the corn-soy rotation, shallow-disk injection had greater potential for N2O emissions than surface application with manure or inorganic fertilizer. 

Soil Carbon Sampling

Soil samples were collected in Spring 2014 from 0-5cm and 5-15 cm depth to compare: 1) soil carbon (C) levels from diverse no-till dairy crop rotations, 2) different methods of nitrogen (N) application in the corn-soy rotation and 3) the evaluate the effect of summer tillage vs no tillage in the pest rotation. In broadcast manure plots, 15 soil cores per plot were collected. In the injected manure plots to account for the 30 inch spatial separation of the bands, four sets of five soil cores 6 inches apart across the crop row were collected, for a total of 20 soil cores per plot. The soil samples were sent to the North Carolina State Soil Testing Lab where they were analyzed for elemental carbon. Data was analyzed with SAS using a MIXED nested split plot ANOVA model.

2014 Soil Carbon Results

Soil C levels differed significantly from 0-5 cm depth across the crop rotations. The manure and pest rotation had 17.52 and 5.42% higher C than the control rotation, respectively (Figure 12). Among the treatments in the rotations, the red clover with injected manure (manure rotation) had the highest (2.16%) C level and the fertilizer treatment in the corn-soy rotation (control rotation) had the lowest (1.6%) C level (Figure 13). The C levels from the treatments in the manure and pest rotation did not differ significantly from the corn–soy rotation with broadcast manure. This is likely because only corn grain is harvested in the corn-soybean rotation and the corn stover left in the soil contributed to the soil C stock. From 5-15 cm depth, the differences were not significant across the crop rotations. When comparing C levels in the corn-soy rotation; from 0-5 cm, the broadcast and injected manure treatments had higher C levels compared to the fertilizer treatment; 24.2 % and 7.03% higher respectively. The differences were not significant from 5-15 cm soil depth (Figure 14). In the pest rotation, we compared soil C levels in the reduced herbicide plots that had been plowed in August 2013 to terminate the alfalfa and orchardgrass, versus the standard herbicide treatment in which alfalfa was terminated with an herbicide prior to planting winter canola without tillage. In spring 2014, in the 0-5 cm depth, soil C was 51 % higher in the no-till treatment than the plowed soil. There were no significant differences between tillage vs no till from 5-15 cm soil depth (Figure 15).

Fall Manure Nutrient Conservation- Satellite Experiment

In the second year of data collection, we continued to evaluate different management strategies that could conserve nitrogen from fall-applied manure for the following corn silage crop. We hypothesized that when fall manure applications were coupled with a winter annual, cereal rye, corn silage yields would be higher when manure is: i) applied to a rye cover crop rather than rye silage, ii) injected rather than broadcasted, and iii) applied later in the fall (November) rather than earlier (September). In 2013-2014, each factor- how the winter annual was managed, when manure was applied, and how the manure was applied; was evaluated at two levels. In 2014-2015, an additional level of no winter annual was included as a winter annual factor increasing the number of treatments to 12. In 2015, rye growth and total nitrogen take up by the aboveground rye biomass were about 191% and 280% greater than in 2014. Similar to 2014, in 2015 when there was a winter rye established, the amount of biomass production and total nitrogen taken up differed based on how the rye was managed. When the rye was terminated early, on May 11, 2015, there was no difference in rye biomass or total nitrogen taken up by the cover crop based on how manure was applied (injected or broadcasted) and when the manure was applied (on September 30, 2014 or on November 13, 2014) (Figure 16). When the rye grew for an additional 10 days and was harvested as silage versus terminated as a cover crop, rye silage produced eight to 10 fold more dry matter and had taken up roughly six to 10 fold more N/A than the rye cover crop. In both 2014 and 2015, 10 days after the rye cover crop was terminated, rye silage took up and produced a significant and profitable forage crop yield. Further, rye silage yields differed based on how the manure was applied and when the manure was applied. After an early application of manure in late September, rye silage yields were about 36% higher when manure was injected than when broadcasted. Although yields did not differ based on application method after a late application, when manure was injected later in the fall (November), yields were 22% lower than an early fall, injected manure application. We attributed differences in yields after early and late injected manure to damage caused by injecting after planting the winter annual. Due to poor seed germination after the first planting on October 10, 2014, rye was replanted on October 27, 2014. The late manure application was 17 days later and caused more damage than in the first year of the experiment when rye was established earlier (Oct. 4, 2013). With injection bands 30 inches apart and rye rows planted on 7.5 inches, injection bands did not damage all planted rows uniformly. When injection bands intersected rye rows in 2014, there was only about 8% loss. By contrast, in 2015, when rye was replanted less than 3 weeks later, rye loss was 46% when injection bands intersected rye rows. Though rye silage yields differed by manure method and time, nitrogen taken up by the forage differed only by the method of application. After both an early and late application, the average amount of nitrogen taken up by the crop was about 48% greater when manure was injected. After an early fall manure application, more nitrogen was conserved for rye growth and uptake when manure was injected. In the late application, despite rye damage, nitrogen conservation was greater when manure was injected than broadcasted (Figure 16). 
Corn yields in 2015 were on average 19% higher than in 2014 but followed the same trends. Corn yields differed based on how the winter annual was managed. Contrary to what we would expect without additional nitrogen inputs, corn yields were highest when there was no winter annual present; 8.6% and 22% higher than corn after a cover crop and rye silage crop respectively. With differences in yield based on how the winter annual was managed- no rye planted, rye cover crop, and rye harvested as silage; we suspect there was a winter annual effect on corn, other than nitrogen, that wasn’t measured. When analyzing yields when manure was applied and no winter annual was planted, the method of application and time of application had no effect on corn yields. When corn followed a rye cover crop, yields were about 13% higher than after a rye silage crop. With no additional fertilizers applied, corn yields after a cover crop were about 23% and 22% higher when manure was injected and applied later respectively (Figure 17 a-b). When corn followed a harvested rye silage crop, there was a difference in yields based on how the manure was applied, but timing of manure application had no effect. When manure was injected, corn yields that followed were about 30% higher than when broadcasted (Figure 17 c-d). 

Fall Manure Nutrient Conservation- Satellite Experiment Summary

When managing the winter annual rye as a cover crop, the rye was terminated before differences in treatments were significant. The amount of rye growth and nitrogen taken up by the aboveground biomass did not differ based on method and time of application. As hypothesized, corn that followed a rye cover crop did yield higher than corn following a rye silage crop, when manure was injected and applied later. When managing the winter annual as double cropped rye silage, the rye grew an additional 10 days and there were differences in rye silage yields and total nitrogen uptake based on method and time of application. When manure was applied earlier in the fall, more nitrogen was conserved and available for rye growth when manure was injected.
After a late application of manure, rye silage yields did not differ based on injected or broadcasted manure. Contrary to 2014, there was a difference in yields between the time of application and injected manure. In 2014, when manure was injected in both the early and late fall, rye silage yields did not differ. However, in 2015, due to replanting close to the late application date, yields after a late, injected manure application were reduced likely due to an increase in rye damage. Despite incurring damage, more nitrogen was conserved for the rye when manure was injected. Corn that followed rye silage yielded differently based on the method of application; timing did not make a difference in N-carryover for the corn. More nitrogen from fall applied manure was conserved for the corn when manure was injected.   Although yields of corn that was not fertilized after rye silage were lower than unfertilized corn following no winter annual and a rye cover crop, total harvested forage was greater when rye was double cropped before corn. Based on these consistent and significant two years of agronomic results, we have been presenting the results and making recommendations for farmers, crop consultants, and educators at various outreach events based. We are continuing analyses on soil samples and lysimeter data to quantify the environmental impact of these nitrogen management strategies.

Pest Rotation: Yields

Crop yields were collected for each crop entry point in the PEST ROTATION in 2015; data was analyzed with a split-plot, mixed ANOVA model using PROC MIXED of SAS for all crops that were managed with reduced herbicide practices in the rotation. When significant interactive effects were found, the SLICE function was used to determine statistical significance. In 2015, Weed management comparisons, reduced herbicide (RH) and standard herbicide (SH), were not significantly different across crop entry points in the PEST rotation (Table 2). When crop yields were compared individually between the reduced herbicide with standard herbicide treatment, the soybean yield was 10.60% higher (p= 0.05, Table 2) in standard herbicide treatment compared to reduced herbicide treatment. Possible explanations for this yield difference are discussed further below, but are likely due to differences in soybean populations, weeds, and soil moisture.

Across Rotations Yields:

We also compare corn and soybean yields among our two diverse rotations (PEST and MANURE rotations) and the one low-diversity rotation (C-S rotation) (Project Schematic). Similarly to 2014, soybean yield in 2015 did not differ between the PEST and C-S rotations and did not differ between RH vs. SH and IM vs. BM treatments nested in each rotation respectively (Table 3). Corn grain yield in 2015 was similar in the MANURE and C-S Rotation (p = 0.30; Table 3), and there were no significant differences between the two injection and broadcast manure treatments in either rotation. 

Weed management in soybean and corn plants in the pest rotation

In the Pest Rotation, a Standard Herbicide regime in soybeans and corn silage was compared to a Reduced Herbicide regime that included a split-split nested model. In both corn and soybeans, herbicides are banded over 10 inches (24 cm) of the crop row at planting The nested reduced herbicide treatment compared two post emergent weed control strategies: two high residue cultivation events versus a broadcast post-herbicide spray. This nested post-emergent herbicide treatment comparison was added in 2013 in response to Advisory panel member feedback that emphasized no-till farmers would not use a high-residue cultivator. Rye cover crops preceding soybeans and corn in 2015 were sparser stands than observed in previous years due to poor seed quality. For this reason, in 2015 rye was sprayed with a burndown control in all treatments, and the roller crimper was not necessary in any treatment. There were no planting difficulties in soybeans, as had occurred in earlier years of the study. Rye residue did not act as barrier to establishment although dry weather conditions were present at the time of emergence and presented difficulties throughout the region. Data collection in the corn and soybean treatments included: rye cover crop dry matter before burndown, grain crop population, weed density before and after post-emergence treatments, weed biomass before harvest, and grain yield. Data was analyzed using a nest split-plot MIXED ANOVA model in SAS. Weed biomass was significantly larger before grain harvest in the Reduced Herbicide with High Residue Cultivation treatment (RH-HR) than the other three treatments (Table 4). While the weed biomass measured in the RH-HR treatment was below levels that could impact grain yield, weed biomass was higher than previous years of the study. A number of factors could have contributed to this increase including above average rainfall in June, the low rye cover crop residue, and difficulty in optimizing cultivation timing. Grain yield in both RH treatments and the SH 76 cm treatment were significantly lower than the 38 cm soybeans in the SH treatment (p =0.06). Lower soybean plant populations (p =0.06) in the RH treatments and SH 76 cm treatment compared to the 38 cm soybeans likely explain some of the lower yields . Furthermore, high residue cultivation has been shown to reduce soil moisture and negatively impact soybean yield recently in organic reduced tillage studies at the Penn State and could have also contributed to reducing yields during the dry late summer weather. For corn silage in 2015, there was no nested treatment within the standard herbicide regime but in the reduced herbicide regime, the nested post-emergent weed treatment was the same as in soybean (high residue  cultivation or post herbicide). Due to this unbalanced design, pairwise comparisons were made among the three treatments on rye cover crop biomass before corn grain planting, weed biomass before harvest, and corn silage yield using a split-plot MIXED ANOVA model analyzed in SAS. As in soybeans, the rye cover crop preceding the corn silage was minimal when compared to earlier years. When the weed biomass was analyzed there were significant differences between each of the treatments (Table 5). The Standard Herbicide treatment had minimal weeds while the two Reduced Herbicide treatments had significantly greater weed biomass. The Reduced Herbicide with High Residue Cultivation (RH-HR) had the greatest weed biomass and was significantly larger than the SH and Reduced Herbicide with Post-emergent Broadcast treatment (RH-PH). While the RH-PH treatment had a smaller weed biomass than the RH-HR treatment, it was still significantly larger than the SH treatment. These weed biomass levels deviate from the pattern observed in the past few years, where the SH and the RH-PH treatments had statistically similar weed biomass. Weeds remained below crop yield thresholds across all treatments, but could contribute to weed populations in future seasons.

Weeds varied across the six years of the study and were influenced by a number of different factors (Figure 18). In 2013, management was altered to better maintain weed control, as is reflected in the 2013 and 2014 weed biomass. The weed levels in corn can possibly be attributed to weed management in the preceding soybean and other crops. Corn is the last row crop within the rotation and the weed biomass observed is possibly influenced by ineffective weed control earlier in the rotation. A trend in increasing biomass through the rotation is not supported by the lack of weed biomass in corn in 2014 and the variation between weed biomass in soybeans. The larger weed biomass in 2015 is likely due to compounding factors such as the lack of weed suppressive rye cover crop and the above average June rainfall that made use the of the high residue cultivator difficult to time, reducing effective weed control.

To provide options for no-till farmers in the reduced herbicide corn and soybean crop treatments, we will continue to evaluate banding the herbicide over the crop row, followed by two post-emergent weed control options: i. the high residue cultivator, ii. post-emergent herbicide, which is the only option our Advisory panel farmers report no-till farmers would implement.

Insect control

We compared differences in pest populations and damage among the conventional corn-soy rotation and the two diverse, six-year rotations. Over the 2015 season, among other ongoing evaluations, we assessed effects of potato leafhopper resistant alfalfa varieties on potato leafhopper populations, and the effects of clover cover crop species on slug damage in the following corn crop, and European corn borer damage. We also measured insect predation of sentinel prey for 24 hours in June, July and August and compared insect predation in the corn-soybean rotation that used pre-emptive insect control to the IPM insect control practices of the diverse rotations. Similar to what we have observed in previous years, in June insect predation levels were higher in the diverse rotations than the corn-soybean rotation (Figures 19 and 20).

Potato leafhopper-resistant alfalfa

Beginning in 2013, we planted potato leafhopper resistant (PLR) alfalfa varieties in the enhanced conservation cropping system treatments (Reduced herbicide and Injected management treatments) to non-resistant alfalfa in the SH and BM management treatments. In both first and second year alfalfa stands, we found a peak in potato leafhopper (PLH) populations around the end of June and beginning of July (Figure 21, a-d). In the Manure Rotation at the beginning of July, the first year alfalfa stands in the broadcast manure/ nonresistant variety alfalfa (BM) treatment had higher PLH populations than the injected manure potato leafhopper resistant (IM/PLR) variety of alfalfa, but these treatments did not differ over the rest of the season (Figure 21a). In the first year alfalfa in the Pest Rotation, the standard herbicide (SH) treatment needed to be sprayed twice to control PLH populations compared to once for the reduced herbicide/potato leafhopper resistant (RH/PLR) treatment (Figure 21c). It is not clear, however, if the lower pesticide use was due to the RH/PLR treatment or from having a mix of alfalfa and orchardgrass compared to pure alfalfa. Because potato leafhopper resistant (PLR) varieties take time to establish and develop the trichomes necessary to fend of PLH, we hypothesized that the resistant variety would reduce PLH numbers in the second year. Our assessment of the Manure Rotation revealed one significant reduction in PLH populations (Figure 21b). In the Pest Rotation, we found significant differences in treatments in PLH populations for the month of June (Figure 21d), but the PLR variety was in a mixed stand of alfalfa and orchardgrass and some of reduction in the Pest Rotation may be attributed to the orchardgrass.

Red Clover vs. Crimson Clover

We assessed the effects of manure management and cover crop selection on early season slug damage to corn. At the main plot level, the broadcast manure treatment had 11.5% more plants damaged compared to the injected manure treatment at the V5 corn stage (Figure 22a). There was no significant difference at the V2 stage. At the split-split plot level, there were no significant differences in slug damage between the crimson clover and red clover cover crops (Figure 22b).

European corn borer

At the end of August, we assessed European Corn Borer (ECB) populations in our corn plots by recording feeding damage and lodged corn plants. In corn silage in the Pest and Manure Rotations, there was minimal ECB damage and no significance in feeding or lodging (Table 6a). In contrast, the corn grain in the manure rotation had about 9% damage to the non-Bt variety, compared to no damage in the Bt corn variety in the corn-soybean “control” rotation (P = 0.06; Table 6b). Importantly, the 9% damage in the corn grain in the Manure Rotation increased from 0.5% damage that we measured in 2014 (Table 7b). These results indicate that ECB populations have increased since last year (Table 7a, b), but population levels still remain low relative to the economic injury level of one ECB per plant. If we have flexibility in our hybrid choice for 2016, it might be prudent to move to a Bt corn variety targeting ECB to knock back the ECB population. Alternatively, we can accept that ECB remained relatively low in 2015 and unlikely caused economic damage, continue to monitor ECB populations in 2016, and then determine if a switch to Bt variety for corn grain would be prudent.

Forage crop comparison

To assess the value of the SH vs. RH forage treatment comparison over time (alfalfa versus alfalfa and orchardgrass, with annual companion crops), we examined the forage crop yields, weeds, crop quality, and economic returns of the forage crop establishment and second year stands from 2011-2013 when the annual companion crops were pea and triticale. Economic forage values were calculated for each harvest based on based on crop yield, crude protein (CP), and total digestible nutrients (TDN) relative to a Pennsylvania reference forage appropriate for each treatment harvest (see Table 8) with the method described in Hall and Marshall, 1996. The reference forage quality values and prices for each hay type and treatment and year were obtained from Pennsylvania Dairy Historic Feed List:

( and are shown in Table 8. Cash values were established at which the forage nutrients above the reference forage value could be obtained by purchasing corn (Zea mays L.) grain and soybean (Glycine max L.) meal for sources of TDN and CP, respectively. Corn and soybean meal were priced according to the Pennsylvania annual reference price also listed in Table 8 and obtained from the Pennsylvania Dairy Historic Feed List ( feed-price-list). The total economic value of all harvests for the establishment year, second year of production and total value over two years was compared between treatments.
Costs of production were calculated as the sum of the variable costs of seed, fertilizer, herbicides, insecticides, labor, fuel, and custom hire; fixed costs such as land and equipment costs were not included. The variable costs were summed for each year and subtracted from the total economic value of the forage harvests for each year to calculate the economic return. The sum of the economic return for year one (the establishment year), year two and the total for the two years for the RH and SH treatments were compared with PROC Mixed of SAS with three years of establishment and second year of production as random blocks or replications.

Forage Yields & Weeds

In all three establishment years, the addition of pea and triticale companion crops to alfalfa and orchardgrass in the RH management resulted in significantly higher forage yields compared to pure alfalfa in the SH management in the first harvest, while the opposite was true in the second harvest (Fig. 23, A-C). In the first harvest, pea and triticale dominated the forage stands in the RH management, leaving a small proportion of alfalfa and orchardgrass to recover and fill in the stand in time for the second harvest. By the third harvest, however, no difference in yield was observed between RH and SH management in both 2011 and 2012 establishment years (Fig. 23, B & C), with alfalfa and orchardgrass being the main components of the RH stands. A third harvest was taken in the SH management only in 2010 (Fig. 23, A). When summed for the year, annual forage yield was significantly higher for the RH management than the SH management in 2011 and 2012, but was lower in 2010 (Table 9), when SH was harvested three times while the RH was only harvested twice. In the second year, at the first harvest, forage yield was significantly higher in SH compared to RH management in 2011 and 2012 (Fig. 23, B & C), but not in 2010 (Fig. 23A). When harvests were summed for the second year of production, annual forage yield was a significantly 21% higher in SH compared to RH management in 2012 (2nd year of 2011 stand) (Table 9). In 2012, the second year of 2011 stand, the alfalfa and orchardgrass in the RH management had less growing time as it was cut two weeks earlier than alfalfa in the SH management to obtain high quality forage for a dairy herd.

Across harvests in the three establishment years and in the first harvest in the 1st production years, weed biomass was largely not different in the RH compared with the SH management aside from in a few instances. Weed biomass in RH management was significantly higher than in SH management in the 2nd harvest in 2010, the 2nd harvest in 2012, and the 3rd harvest in 2012 (Fig. 23, A & C). At the second harvest in 2010, weeds comprised 43% of the RH stands compared with 11% in the SH stands. It should be noted, however, that double the pea seeding rate was used in 2010 in comparison with 2011 and 2012, resulting in a stunted alfalfa and orchardgrass post pea and triticale harvest that was susceptible to weed invasion. In comparison, at the second and third harvests in 2012, weeds comprised 16% and 26% of the RH stands, respectively, compared to 6% and 3% in the SH stands. In the second year, at the first harvest, weed biomass was significantly higher in the RH than in SH management in 2010 only (Fig. 23, A), but comprised less than 1% of the stand in both treatments. This confirms that the companion mixes in the RH treatment effectively suppressed weeds until after first harvest when weeds increased, but eventually attained similar weed suppress to the SH treatment. 

Forage Quality

Aside from a few instances, forage quality of each harvest in all three years when the forage was established and in the second year was consistently higher in the pure alfalfa (SH) compared to the RH treatment. In the establishment year for instance in most harvests, percent CP, percent NEL and RFV were significantly higher in the pure alfalfa (SH) than the RH (alfalfa, orchardgrass, pea and triticale) management, and the percent NDF was significantly lower in the SH than RH management of forage stands (Table 10A). Acid detergent fiber (ADF) was the one exception, with significantly higher percent ADF in RH than SH management in the first harvest, but not in the other harvests (Table 10B). Forage quality was also higher in the SH and RH in the second year of production.


Although the first harvest of the RH treatment and the total yield of the RH treatment was higher in the establishment year, the quality of the RH treatment was consistently lower than the SH treatment. In the establishment year, the economic value calculated based on the crop yield and quality of each harvest (Table 11) did not differ significantly between RH and SH treatments (Figure 24) over the three years of the experiment. In the second production year, however the pure alfalfa SH averaged 37% more economically valuable than the RH treatment. Since both treatments produced more yield in the second year, when the economic values were summed across both the establishment and second year, the two year economic value of the SH treatments was 50% higher than the RH treatment (Figure 24).

The Virtual Dairy Farm: Economics of Feeding the Herd

The virtual dairy operation was designed to represent a typical Pennsylvania tie-stall barn for the lactating herd and a bedded pack for young-stock and dry cows. Upright silos and Ag Bags are used to ensile forages. All forages, corn grain, soybeans and canola meal are fed to the herd, as a total mixed ration. Using the crop yield and quality produced with the 2001 NRC dairy cattle nutrition model, the dairy herd’s milk production was simulated. Scenario 1 included: broadcast manure and standard herbicide (BMSH). Scenario 2 included: injected manure and reduced herbicide (IMRH). To identify system benefits, trade-offs and opportunities to improve practices, multiple performance indicators were examined: crop yield and quality, energy use and production, and farm profitability. The profitability of the farm was evaluated for both scenarios using the FINPACKR Year End Analysis tool (FINAN) over four years (Center for Farm Financial Management, University of Minnesota, 2015). Profitability between the two scenarios was similar using key performance indicators of current ratio (liquidity), return on assets (profitability), debt coverage (repayment capacity), and dairy net return over labor and management per cow (Figure 25). The virtual dairy dealt with real world events such as the volatility of the milk and grain markets. Weather conditions affected forage inventory and quality, which impacted crop sales and milk income. The virtual farm dealt with drought conditions in 2011 and 2012, which affected the yields of both hay-crop forages and corn silage. The severe drought in 2012 resulted in an increased unit cost/ton for the forages raised because of the low yields. This coupled with the increased market price of purchased feeds caused a substantial increase in feed costs/cow/year in 2013 (Tables 12 and 13).

Over the four year period on average the BMSH scenario showed a slight advantage over IMRH when comparing Net Farm Income per cow ($1904 versus $1720). Higher crop sales in the BMSH scenario showed a whole farm profitability advantage because of producing both pure alfalfa and alfalfa/grass mixtures. However, examining the dairy enterprise only (not accounting for cash crop sales), the IMRH scenario showed a slight advantage over BMSH ($758 versus $695). This was the result of incorporating a small grain silage mixture in the rotation that allowed three months of feed for the dry cows and heifers, which saved on the corn silage inventory.  The additional small grain silage had ramifications the following fall when corn silage inventory was reduced by 2011 drought conditions. The IMRH had corn silage carry over when the BMSH that did not which effected milk production and milk income, because the BMSH scenario had to feed fresh corn silage, which has shown to reduce production compared to feeding corn silage that is fermented.  Due to forage and feed limitations in drier years, 20 acres of corn silage were substituted for wheat in 2013. The wheat straw had been used for bedding and the grain sold off farm. In 2014, 20 acres of canola/red clover was replaced with rye silage/sorghum sudangrass/crimson clover. The additional acreage for corn provides a forage/grain buffer for years when weather limits crop yields, and the rye silage is more suitable quality forage for dry cows and heifers. Evaluating the virtual farm in the real world, the interpretation for both strategies would be sustainable, environmentally compliant and profitable.

Whole Farm Scale: Energetic Analysis

Penn State’s Farm Energy Analysis Tool (FEAT; was used to quantify the fossil energy inputs and GHG emissions of the NESARE dairy cropping systems from 2011 as compared to two other typical dairy farms. The other two farms required less acreage than the NESARE systems but one only grew feed and forage, and the other only grew forage on-farm, while the NESARE system grew feed, forage, and fuel on-farm. This analysis revealed that fossil energy inputs can be reduced by growing forage + feed on dairy farms using animal manure and legume crops in rotation with corn and soybean crops rather than importing those feeds. Importing feeds is energy intensive relative to growing feeds on a dairy farm, due to the exclusive use of nitrogen fertilizers and reduced tillage on non-integrated grain production farms. The results of this study are published at the Journal of Agriculture, Ecosystems and Environment (Malcolm et al., 2015). Since conducting this analysis, we have additional years of cropping system performance and made some changes to the cropping systems. We are currently in the process of entering the practices and yields into FEAT to analyze and compare the fossil energy inputs and GHG emissions of the two NESARE dairy cropping system farm scenarios for additional scientific publication and outreach education activities.


We made significant progress on the development of our long-term, database that is designed with a standard format to minimize errors and make it easy to query and select specific datasets for analysis. Developing the tool, archiving the research protocols, recording the correct meta-data, and double-checking the data was a valuable to coordinate and clarify the nature of the many types of data, identify a few errors, and potential confusion for data-sets or years where data collection protocols or changes may have occurred.

Insights gained from the research, potential applications to stakeholders and how these affect plans for the next 3-year cycle.

In the first six years, we changed the crop rotations because of what we learned about: i. slug life cycles and feeding activity, ii. the need for additional corn acres in poor weather years, iii. the benefits of red clover underseeding in small grains as a green manure prior to corn versus hairy vetch, iv. how to fit canola into a PA dairy crop rotation and v. the need for forages that are lower in protein than alfalfa and grass for dry cow and heifer nutrition (and to reduce excess N excretion). Based on this knowledge, we: i. moved alfalfa planting to spring and winter canola planting 2.5 weeks earlier in late summer to avoid the fall peak in slug herbivory activity, ii. replaced winter wheat (grown for bedding; the grain was sold) with another crop entry of corn silage, iii. replaced hairy vetch with crimson clover to evaluate a different green manure crop, and iv. replaced canola that could not be planted early enough after corn silage with rye silage/ sorghum sudangrass, to produce more dry cow and heifer forage. With the knowledge we gained, we can make more informed recommendations to dairy producers, extension educators, and crop and nutrition consultants about dairy crop rotation strategies. Particularly with the above changes, in the final three years, we found that both dairy cropping systems provided strategies for dairy farmers to produce the majority of the dairy feed and forage, and be profitable. Further, through diverse rotations, IPM and practices to protect insect biodiversity, both 6 year rotations controlled insect pests and benefitted from higher activity of predatory insects compared to the corn-soybean rotation that relied on preemptive insurance-based pesticide control practices. Soil quality indicators were also higher or similar in the diverse dairy rotations compared to the corn–soybean rotation. Although within the pest rotation, soil carbon was 50 % lower at 0-5 cm after tillage compared to no-tillage. When we compared the enhanced 6- year dairy conservation cropping systems (manure injection and reduced herbicide systems) to the standard no-till 6-year dairy cropping systems, off-farm imports of fertilizers and pesticides, as well as nutrient losses were reduced. Overall, these results reveal multiple opportunities for dairy farmers to enhance their dairy farm sustainability.

Impacts and Contributions/Outcomes

Information that we have learned from the NESARE Sustainable Dairy Cropping Systems is presented as several outreach and extension type activities including field days, workshops, fact sheets, field visits, symposiums, and regional and national scientific meetings. With funding from an NRCS CIG grant, we have also produced three videos featuring farmers and commercial manure haulers discussing manure injection and cover cropping that are linked to multiple extension websites. The videos can be found on YouTube at the following links:

  1. Shallow Disk Manure Injection – Penn State University:

      2.Cover Crops Rationale: 

  1. Cover Crop Species and Establishment:

1.NESARE Dairy Cropping System Project Updates from 2014 and 2015:

Karsten, H. D. et al. Evaluation of Integrated Diverse Dairy Cropping Systems Designed for Sustainability & Ecosystem Services. ASA, CSSA, SSSA, annual meeting, Minneapolis, MN, 15-18 Nov, 2015.

Karsten, H. D. et al. 2015. USDA Climate Hub presentation “Sustainable Dairy Cropping Systems Research “

Karsten, H. D. et al. Penn State Sparks Donor Circle Research Tour, Rock Springs Agronomy Farm, Aug. 14, 2015.

Karsten, H. D. et al. NE Dairy Cropping System Research Results and updates. Presented at summer extension in-service for field and forage crop team, Rock Springs, Pennsylvania, July 2015.

Malcolm, G. M. 2014 and 2015. NESARE Dairy Cropping Systems Research Update. Triad Cropping Systems Research Symposium March, 2014 & 2015.

Karsten, H.D. et al. “NESARE Diversified Dairy Cropping Systems “ Cows to Crops Conference. Grantville, PA. November 11, 2014.

Karsten, H. D. 2014 Northeast Region Certified Crop Advisor training, in Syracuse, NY, “ Penn State’s Diversified Dairy Farm Cropping Systems Research; Lessons Learned” , December 3, 2014.

Karsten, H. K. 2014. PSU Diversified Dairy Cropping Systems Project at the Centre County Watershed Summit at the Nittany Lion Inn, November 3, 2014.

Karsten, H. D. et al. NESARE Dairy Cropping Systems Research Update. Plant Science Dept. Seminar. Sept. 19, 2014.

Karsten, H. D. et al. “Lessons Learned from the PSU Diversified Dairy Cropping Systems Project” Field Day with participation from all of our research team on July 1, 2014 at our PSU experimental site.

2.Nutrient Management Team activities from 2015:

Beegle et al. Extension Activities

Beegle, D. Statewide Nutrient Management Workshops. Workshops conducted during the past year: 10/21/2014,4/8/2015, 5/6/2015, 5/13/2015, 9/15/2015 (There were a similar number of workshops each year). Results from this project related to manure application methods and general whole farm nutrient management were used as examples in the workshop

Beegle, D. County Soil Fertility Workshops. Workshops conducted during the past year: 1/20/15, 3/18/2015, 11/11/15, 11/13/15 (There were a similar number of workshops each year). Results from this project related to manure application methods and general whole farm nutrient management were used as examples in the workshop

Graduate Student Extension Publications

Get the most out of fall manure. Rachel Millron. Progressive Dairyman. Vol 29 p102-103. Aug, 24, 2015.

 Graduate Student Extension and Research Talks

Shallow disk injection versus broadcasting of manure: a field study. Emily Duncan, Peter Kleinman, Doug Beegle, Curt Dell, Heather Karsten. North American Manure expo, Chambersburg, PA, July 14-15, 2015.

Contributed to development and presentation of an introduction to manure management on “field lyimseters” or plots that are hydrologically isolated for the measurement of surface runoff and subsurface flow. Emily Duncan, Rachel Milliron, Peter Kleinman, Doug Beegle, Curt Dell, Heather Karsten. Field Crops Clinic- Penn State Extension Diagnostic Clinic, 2015.

Using a winter rye crop to conserve fall manure-N for crop production. Rachel Milliron, NRCS soil health workshop, Big Flats, New York. Nov, 2015.

Getting the most out of fall manure. Rachel Milliron, Penn State’s Ag Progress Days Nutrient Management, Rock Springs, Pennsylvania. Aug, 2015.

Utilizing fall manure to double crop winter and summer annual forages. Rachel Milliron, North American Manure Expo, Chambersburg, PA, July 14-15, 2015.

Graduate Student Research Poster presentations

Impacts of Fall Manure Application Method and Timing on Nitrogen Conservation for Winter Annual and Subsequent Corn Crops. Rachel Milliron, Heather D. Karsten, Douglas

Beegle, William Curran. ASA, CSSA, SSSA annual meeting, Minneapolis, MN, 15-18 Nov 2015.

Understanding and Controlling Hillslope Hydrology to Assess Water Quality within Sustainable Dairy Manure Management. Emily Duncan, Peter J. A. Kleinman, Douglas B.  Beegle, & Curtis J. Dell. ASA, CSSA, SSSA annual meeting, Minneapolis, MN, 15-18 Nov 2015.

Nitrous oxide emissions from diverse no-till dairy crop rotations. Maria Alejandra Ponce de Leon, Curtis Dell, and Heather Karsten. Dairy Environmental Systems and Climate Adaptation Conference. Ithaca, NY, 27- 29 July 2015.

Temporal Analysis of Nitrous Oxide Emissions from a Pennsylvania No-till Dairy Cropping System. Maria Ponce de Leon, Pennsylvania State University; Curtis J. Dell, USDA-ARS Pasture Systems & Watershed Management Research Unit; Heather D. Karsten. ASA, CSSA, SSSA annual meeting, Minneapolis, MN, 15-18 Nov 2015.

Impacts of fall manure application method and timing on nitrogen conservation for winter annual and subsequent corn crops. Rachel Milliron. Poster presented at ASA, CCA, SSSA annual meeting, Minneapolis, MN, Nov 15-18, 2015.

Conserving nutrients from fall applied. Rachel Milliron, Poster presented at 5th Annual Triad Symposium, University Park, PA, 2015. vii. Conserving nutrients from fall applied manure. Rachel Millrion. Poster presented at Gamma Sigman Delta Research Expo, University Park, PA. 2015.

3.Virtual Dairy/Economics Team from 2015:

 1. Winter Rye Offers Options for Fall Applications of Manure. Virginia Ishler. Lancaster

Farming, August 22, 2015 (A22).

2. Balancing Expertise Helps Balance Dairy Nutrition. Virginia Ishler. Livestock &

Environment, October 4, 2015.


4. Weed Management Team from 2015:

Curran et al. Extension Activities

Herbicide Resistant Weed Management seminar was presented at six locations during the

winter of 2015 (230 attendees):

  • Lehigh County, Jan 21
  • Franklin County, Jan. 28
  • Blair County, Feb. 17
  • Berks County, March 17
  • Lancaster County, March 18
  • Franklin County, March 19

Curran, W. Are cover crops a practical means for suppressing weeds? FarmSmart Annual Conference, Guelph Ontario, Jan. 14, 2015 (100 attendees).

Curran. W, G. Roth, C. Dillon, C. Houser, R. Hoover, J. Wallace, M. Dempsey, S. Mirsky, and M. Ryan. Improving the potential for interseeding cover crops in corn. FarmSmart Annual Conference, Guelph Ontario, Jan. 14, 2015 (150 attendees).

Curran, W. Herbicides cover crops, and interseeding. Seedway Crops Conference,

Millhall, PA, Feb. 18, 2015 (100 attendees). Curran, W. Life and death of a cover crop. Adams County Conservation District Annual Crops Meeting, Gettysburg, PA. Feb. 25, 2015 (100 attendees).

Curran, W.S. Herbicide resistant weeds, a complex problem wanting simple solutions. Dept. of Plant Science Seminar, Penn State University, University Park, March 2, 2015 (50 attendees).

Curran and Lingenfelter. 2015. Cover crop adoption and utilization in Pennsylvania; a combination of staunch enthusiasm and anxious uncertainty. NEWSS 53:69 (50 attendees).

Keene, C.L. and W.S. Curran. 2015. High residue cultivation as an integrated weed management tactic in no-till corn and soybean. NEWSS 5:69 (150 attendees). viii. Caswell, K., E. Synder, W. Curran, H. Karsten, and G. Malcolm. 2015. Impact of adaptive management on weed control in a long-term, Dairy cropping system. NEWSS 32:69 (150 attendees).

Caswell, K. W. Curran, S. Mirsky, G. Roth, M. Ryan, and J. Wallace. Evaluation of different cover crops in interseeded corn. ASA, CSSA, SSSA annual meeting, Minneapolis, MN, 15-18 Nov 2015, 112-11.

Wallace, J. and W. Curran. 2015. Preemergent herbicide programs for interseeded cover crops in Mid-Atlantic corn production. ASA, CSSA, SSSA annual meeting, Minneapolis, MN, 15-18 Nov 2015, 342-11.

Roth, G. W. Curran, M. Ryan, and S. Mirksy. 2015. Interseeding cover crops in corn: impacts on corn yield and cover crop biomass production in the Mid-Atlantic. ASA, CSSA, SSSA annual meeting, Minneapolis, MN, 15-18 Nov 2015, 138-12.

Caswell, K. W. Curran, S. Mirsky, G. W. Roth, M. Ryan, and J. M Wallace (2015). Evaluation of Different Cover Crops in Interseeded Corn. ASA, CSSA, SSSA annual meeting, Minneapolis, MN, 15-18 Nov 2015.

5. Insect/Slug Management Team:

Tooker et al. Extension Activities

Ten winter extension events and six field days relating to the value of diverse rotations, natural enemy populations, and IPM for managing insect and slug populations in grain and forage systems. At these 16 meetings, we presented to 1285 farmers and agricultural professionals.

Cover Crop Termination Timing Effect on Soil and Water Conservation, Slugs, and Yield in Pennsylvania No-till Corn and Soybean. Heidi Myer, Heather D. Karsten, John Tooker, and William Curran. ASA, CSSA, SSSA annual meeting, Minneapolis, MN, 15-18 Nov 2015.

Does Pterostichus melanarius (Coleoptera: Carabidae) induce fear in slugs: Relevance for biological control. Busch A.K. and J.F. Tooker. Entomological Society of America Meeting, Minneapolis, MN, 15-18 Nov 2015.

We also collaborate with colleagues whom are conducting cropping systems research to organize the:

  1. Annual Triad Cropping Systems Symposium
  2. Undergraduate Research Assistants Orientation Tour to Cropping Systems Research

projects at the PSU Agronomy Research Farm

6. Publications:

GM Malcolm, GGT Camargo, VA Ishler, TL Richard, HD Karsten. 2015. Energy and greenhouse gas analysis of northeast US dairy cropping systems. Agriculture, Ecosystems and Environment 199, 407-417.

Publications in revision or preparation for submission:
E. M. Snyder, and W. S. Curran, H. D. Karsten, G. M. Malcolm, S. W. Duiker, J. A. Hyde. Assessment of an integrated weed management system in no-till corn (Zea mays L.) and soybean (Glycine max L.). In revision for resubmission to Weed Science.

E. M. Snyder, and H. D. Karsten, W. S. Curran, G. M. Malcolm, and J. A. Hyde. 2015. Comparison of Red Clover (Trifolium pratense L.) and Hairy Vetch (Vicia villosa Roth) Green Manure Crops in a Winter Wheat (Triticum aestivum L.) to Corn (Zea mays L.) Rotation. In preparation for submission to Agronomy Journal.

G. M. Malcolm, E. Synder, H.D. Karsten, W. Curran, and J. Tooker. Establishing and Managing Alfafla with Annual Companion Crops and IPM for Potato Leafhopper. To be submitted to Agronomy Journal.

Karsten, H.D., G. M. Malcolm, D. Beegle, W. Curran, C. Dell. P. Kleinman, T. Richard, V. Ishler, J Tooker and R. Hoover. Evaluating Strategies for Diversified, No-Till Dairy Cropping Systems Designed to Produce All Forage, Feed, and some Fuel. In preparation for submission to Agronomy Journal

Other Funding Sources and Awards


  1. AFRI Dairy CAP, “Climate Change Mitigation and Adaptation in Dairy Production Systems of the Great Lakes Region” Univ. Wisconsin & 37 Co-PI’s $9,856,576 (PSU:$833,074). 10/2012- 09/2017
  1. NIFA Climate Change “Nitrite Ammonification In Manures and Soils Under Adaptive Management for Climate Change. “ MaryAnn Bruns, Heather Karsten, John Regan, and Curtis Dell“, $560,208, 4/01/2016 – 3/31/2019
  1. EPA. “Center for Integrated Multi-Scale Nutrient Pollution Solutions”. Shortle, J. (PI) and multiple Co-PI’s $2,498,267, 8/01/13 – 7/31/16
  1. NE SARE Professional Development Grant ENE 15-136. “The impact of corn silage selection, harvesting and feeding decisions on income over feed costs. “ V. Ishler, H.Weeks, G.Roth, C.Houser, N.Carutis. $48,874. 10/1/2015-12/30/2018.
  1. USDA ARS Cooperative Agreement “Evaluating Strategies to Adapt Northeast Dairy Cropping Systems to Climate Change Projections” $70,000. C. Alan Rotz and Heather Karsten. Jan. 2016- Dec. 2017 with the opportunity for renewal for a second year.
  1. NESARE Research & Education. “Getting the most out of cover crops: how timing of termination influences soil health, pest control and improved crop production” Heather D. Karsten, William Curran, Sjoerd Duiker, Ron Hoover, and Chris Houser, and John Tooker. $222,044, 9/14 – 8/18.
  1. Beegle, D. Related Research: Nitrogen management on Sorghum Sudan grass (Internal funded) Results in the NESARE project indicate that our N recommendations for sorghum sudangrass may not be adequate for optimum production. This experiment is determining the rate and timing response of sorghum sudangrass to fertilizer nitrogen.


  1. Beegle. D. Improving the Efficiency of Injected Manure with a Nitrification Inhibitor (Funded by DOW) One potential drawback to injecting liquid manure is that a micro-zone of conditions ideal for denitrification may be created at the injection point. This project is looking at the impact of adding a nitrification inhibitor (Nitrpyrin) to the manure to reduce the denitrification losses.


Project team members (faculty, graduate students, staff, and undergraduate research assistants) work collaboratively to conduct this research and report results to multiple audiences (see Research and Outreach activities listed above). We have monthly team meetings to coordinate research activities, share results, discuss how to improve the dairy cropping systems, and plan how to present the results to stakeholder audiences (ex. educators and farmers). Smaller project topic-teams also meet frequently to plan research and outreach activities. A project internal website has our field and data collection calendar with all operations since the project began, and other resources including field maps and rotation schematics, meeting minutes, shared presentation slides etc. This also represents an important institutional collaboration of Pennsylvania State University College of Agricultural Sciences (PSU CAS) and the USDA Agricultural Research Service (USDA ARS). The PSU CAS that has provided essentially all of the graduate student assistantships and tuition for eight graduate students over the past six years, and the USDA ARS has paid for the installation of the lysimeter plots and collection houses, some graduate student assistantship semesters and graduate summer support, the weather station at the site, and labor and supplies for data collection, upgrades, and maintenance of this valuable environmental and agronomic research facility.

Producers and Stakeholders affected by the Research & their Advisory Involvement

Each year our project team presents our research results and modification plans to our Advisory panel. The Advisory panel includes three farmers, a crop consultant whom is active with the PA No-Till Alliance, the regional NRCS director, and the PSU Agronomy research farm manager. We value their input and feedback and often implement their recommendations and test their new ideas. We also consult with the Advisory panels regarding adoption barriers, and how to best present and promote what we have learned; and we invite them to participate in our field days. Surveys of attendants at our field days and extension meeting programs consistently indicate that participants have a new gained new knowledge or an enhanced understanding of the how to implement the conservation cropping system strategies and dairy feed and forage management approaches, as well as the benefits of these practices; and a high percentage of farmers report that they plan to or are considering adopting the practices (ex. see Field Day survey in 2014 Annual Report).

Successes, Challenges and Unexpected Outcomes

Presentation of this Sustainable Dairy Cropping Systems research and the results has been very well received by multiple stakeholders including farmers, cooperative extension educators, crop consultants, NRCS personnel, dairy nutritionists, and PA seed company representatives whom advise dairy farmers. We are often told that more of this type of research that examines how cropping systems impact not just crop yield, but also forage quality, milk production and  farm profitability is what needed. Many stakeholders are also impressed that we have demonstrated that farmers can reduce off-farm inputs, produce more feed through management with onfarm resources, reduce environmental impacts and be profitable. We are told and anticipate that having this “win-win” result after multiple years of variable weather and market prices will be well received by farmers and others.
We have also identified some challenges of promoting adoption of some of the dairy farming practices, particularly balancing cow numbers with farm crop production potential and manure injection on dairy farms. With support from the NESARE PDP grant, the dairy management team (Ishler and Beck) have presented strategies to dairy farmers, crop and nutrition consultants, and the interest and willingness to adopt new cropping systems and feeding strategies has been very positive. Since we have found that producing more feed and forage on farm has multiple benefits, this strategy is one of our on-farm research and extension activity focus themes for the next three years. In addition to communicating the profitability and environmental benefits of this strategy, we will also promote growing winter annual forages with farm manure after corn silage or other summer annual crops. Through our demonstrations CIG NRCS project of 23 on-farm manure injection evaluations with four commercial manure haulers and cooperative extension educators over 3 years, we have gained an in-depth understanding of the challenges and opportunities to promote manure injection on dairy farms. Granted, two of the three years of our on-farm manure injection evaluation had mid-summer dry seasons that limited crop yields and likely any potential yield response to N conserved through manure injection. But many of the dairy farm soils we sampled also have significant organic N reserves due to perennial legume crop production and manure applications, which also likely limited a yield-response to manure-injected conserved nitrogen. And although our CIG NRCS grant covered the cost of the slightly higher fee for manure injection, timely spring planting, rather than the custom manure application cost was often more critical. Because farmers aim to plant corn as early as possible, and spring weather often limits the optimal days for field operations, many dairy farmers and commercial manure haulers are reluctant to engage in any field operations that could delay corn planting such as injecting versus surface applying manure. We purchased manure injection for commercial manure haulers whom were required to help recruit additional farms to try manure injection, if they wanted to retain the injection units. Our cooperative extension educators report that some of the cooperating manure haulers were concerned that they risked losing clients if manure injection reduced their ability to service multiple farms, reducing their commitment to promoting adoption. Given these constraints, one manure hauler in Lancaster County was very successful in addressing some of these challenges and in promoting adoption of manure injection. By adding an additional injection unit (6 vs. 5) and pulling the manure equipment with a truck with GIS, they could cover more ground faster and reduce the time required for manure injection. Working with a local machine shop, they also developed a stronger design of the injection units that made them less vulnerable to damage in rocky soils. In addition, they advertised the manure injection option in Lancaster Farming and actively participated in our on-farm and project field days. They found clients whom were willing to pay for manure injection to reduce manure odor and the sight of manure on rented land where they wished to retain their rental contracts. Later they also serviced farmers in Maryland whom wanted to continue no-till farming but due to new state regulations are required to inject or incorporate manure on highly erodible land. After three years, they were not able to meet the demand for manure injection and so we helped them purchase a second set of injection units to meet the local demand. Through this project and discussions with our Advisory panel we have identified multiple opportunities to continue to promote manure injection; these include: i) livestock farms that have high P index fields or parts of fields where regulations would otherwise not permit manure application due to proximity to surface waters or soils with high P index; ii) farms seeking to reduce odor to retain rental contracts or maintain good relations with neighboring residential units; iii) crop farmers whom purchase manure and have soils are N limited because they don’t have livestock or grow perennial legumes.

Since there is more time after crop harvest in fall for field operations, in this 2013 grant funding cycle we have also studied fall manure injection compared to surface manure application for rye cover or rye silage crops. After two years of autumn manure management research, we have documented enhanced manure N utilization and yield advantage of manure injection over surface application on rye silage as well as the subsequent corn silage crop after rye silage or a rye cover crop. Therefore, our proposal for the next three years includes on-farm trials and extension programs to promote manure injection prior to planting winter annual forage crops, and continuing research at our field site to document manure P nutrient conservation and strategies to optimize winter annual silage production. Recently Dr. Heather Gall, a new Hydrology faculty member in the Department of Agricultural and Biological Engineering, and her doctoral student began analyzing water samples from the lysimeter plots for antibiotics and hormones. They measured some high levels of these compounds after an early spring run-off event after manure had been applied the previous fall. She plans to continue to monitor the water for these emerging contaminates from our manure studies on the lysimeter plots.

Budget report to date:

Funding for this project has been spent as planned on expenses to pay for the farming (ex. farm rent, inputs, labor and maintenance) and research expenses. Research labor expenses include the salary and fringe for the post-doctoral researcher and a few months each year of a research technician, two semesters of graduate assistantship, graduate student summer salary and fringe, undergraduate research wages and fringe for the summer and some hours during the academic year, consulting fees for our Advisory panel members and their travel and some field  day advertising and refreshment fees. The funding also pays for research supplies for maintaining plot edge posts, flagging sampling locations, and sampling materials for crop, weed, insect, slugs and soil sampling, as well as fees for sample analyses (PSNT, plant tissue nutrient and soil fertility analyses, soil quality analyses, feed and forage quality analyses).

 Matching Funds

To conduct this research, we obtained matching funding for graduate stipends/assistantships and tuition for three graduate students from faculty home departments and the PSU College of Agricultural Sciences. We also obtained matching from the Penn State Institutes for Energy and the Environment to fund the development of a data management tool and other interdisciplinary research expenses which were spent to pay some months of a research technician’s salary and fringe and some salary of a staff member whom helped us collect data on the fuel use of the straight vegetable oil tractor and canola oil pressing.

 Unexpected Expenses

After the first year, Penn State increased the fringe rate significantly for all post-doctoral researchers and research technicians, and our post-doctoral researcher, Dr. Glenna Malcolm, was due to be promoted to Research Associate which had a higher fringe rate. Therefore, the largest unexpected expense was for staff fringe which the PSU Department of Plant Sciences graciously helped with. Then Dr. Glenna Malcolm had maternity leave and left in July for a new position. A new post-doctoral researcher Emad Jahanzad began three months later which conserved grants funds to pay his salary and the higher post-doctoral research fringe rate.  

Leveraged funds from other sources

Establishment of this dairy cropping systems project enabled us to participate in and benefit from a NIFA USDA Dairy CAP grant “Climate Change Mitigation and Adaptation in Dairy Production Systems of the Great Lakes Region”. This has funded an Agronomy graduate masters student who is studying nitrous oxide emissions from N amendments for corn production, as well as labor expenses that supports this work including three months of a research technician’s salary and fringe, three and half months of post-doctoral salary and fringe, and undergraduate research wage-payroll hours and fringe.

 This has also helped us establish a new USDA ARS Cooperative Agreement that will fund a postdoctoral research associate to modify IFSM to simulate the nitrogen dynamics we have measured in our conservation cropping systems, and to explore how our conservation dairy cropping systems and strategies such as different crop species may help dairy farmers adapt to and mitigate projected climate change, while protecting air and water quality.

 In the EPA Center for Nutrient Solutions grant, a post-doctoral researcher was funded to assess the potential of our dairy conservation cropping system strategies to reduce the nutrient import to farms, and farm nutrient losses at the watershed scale with the watershed model SWAT.

With soil microbial ecologist MaryAnn Burns as PI, Karsten and Dell are collaborators in a NIFA Climate Change grant to learn how soils and manures can be managed to counteract denitrification and to promote a bacterial process known as nitrite ammonification, the end product of which (ammonium) is not lost directly to the atmosphere. We hypothesize that nitrite ammonification occurs to a significant extent in soils managed using no-till practices and labile carbon amendments, such as animal and green manures, and that manure storage and handling practices can favor nitrite ammonification over denitrification. With funding for a postdoctoral researcher, a graduate student and research technician support, we will 1) measure bacterial groups and labile carbon substrates in manures from dairies of varying size and manure handling systems; 2) measure GHGs and temporal and spatial changes in nitrite  ammonification in no–till soils and tilled soils in our Sustainable Dairy Cropping Systems project; and 3) conduct soil mesocosm studies to determine relationships between substrates, physicochemical conditions, microbial processes, and GHGs to understand conditions favoring nitrite ammonification. Based on what we learned through this research and our extension activities, Ishler, Beck, and crop and dairy management Cooperative Extension educators wrote and were awarded a NESARE PDP grant to train crop consultants, dairy nutritionists, extension educators and farmers to better understand the impact of corn silage harvesting and feeding decisions on income over feed costs. Consultants for crop production and dairy nutrition work together with dairy producers to make more informed and better feed management decisions, with forage quality, feed inventory, and income over feed cost information. A full economic assessment will be completed to evaluate the impact of decisions made. 

A NESARE Research and Education grant awarded in 2014 is funding an Agronomy doctoral graduate student and the research trials on three collaborating commercial farms and at two PSU research farms to explore how to capture more benefits of cover crops by delaying cover crop termination until the subsequent crop is planted. Karsten, Tooker, Curran, Hoover developed this project with Duiker because in this NESARE sustainable dairy cropping systems project, in some years, terminating cover crop residue 10 days prior to crop planting, contributed to reducing establishment and plant populations of the subsequent crop. Through discussions with our Advisory panel and farmers, we learned that “planting green” or delaying cover crop termination could potentially improve subsequent crop establishment and provide additional soil health and pest control benefits.

Proposed Cropping System Modifications

Based on what we have learned in first phase of the six-year rotations, we will modify each of the crop rotations and evaluate them over the next three years: 

1.To assess and compare the impact of tillage on multiple factors, we will convert a split-plot treatment in the corn-soybean rotation to conservation tillage practices.

2. In the pest rotation, the reduced herbicide forage entry of alfalfa and orchardgrass has lower forage quality and economic value compared to the pure alfalfa in the standard herbicide treatment. This has contributed to the slightly lower profitability of the enhanced 6- year dairy conservation cropping systems compared to the standard no-till 6-year rotations. To compare more similar forage crops and improve the forage quality and economic value of the reduced herbicide treatment, we will remove the orchardgrass and compare alfalfa only with or without a companion crop in reduced and standard herbicide treatments. In addition, in the reduced herbicide establishment year, spring triticale has been difficult to obtain, and triticale has not consistently produced a significant yield of small grain forage in the first harvest or a highly weed suppressive canopy (Table 14). Therefore we will replace spring triticale with an oats companion crop. Oats are a readily available, common alfalfa companion crop in the region for early forage production and weed suppression. 


Dr. William Curran
Professor of Weed Science
The Pennsylvania State University
423 ASI Bldg
Dept of Plant Science
University Park, PA 16802
Office Phone: 8148631014
Dr. Glenna Malcolm
Research Associate/Instructor
203 ASI Bldg
Dept. of Plant Sciences
University Park, PA 16802
Office Phone: 8148673021
Dr. Emad Jahanzad
Post Doctoral Research Associate
Penn State University
203 Agricultural Science and Industries Building, University Park
State College , PA 16802
Office Phone: 8148673021
Dr. Curtis Dell
Research Soil Scientist
Agricultural Research Service Pasture Systems & Watershed Management Research Unit
Curtain Road
University Park, PA 16802
Office Phone: 8148630984
Dr. Douglas Beegle
Distinguished Prof of Agronomy
420 ASI Bldg
Dept of Plant Sciences
University Park, PA 16802
Office Phone: 8148631016
Dr. Peter Kleinman
Research Leader & Research Soil Scientist
Agricultural Research Service Pasture Systems & Watershed Management Research Unit
Curtain Road
University Park, PA 16802
Office Phone: 8148653184
Ronald Hoover
Senior Project Associate & Coordinator of On-farm Research
Pennsylvania State University
425 ASI Bldg
Dept of Plant Science
University Park, PA 16802
Office Phone: 8148656672
Dr. Tom Richard
Professor of Agricultural and Biological Engineering & Director, Penn State Institutes of Energy and the Environment
225 Agricultural Engineering
Department of Agricultural and Biological Engineering
University Park, PA 16802
Office Phone: 8148653722
Dr. Tim Beck
Extension Educator - Agricultural Business Management, Cumberland County
Cumberland County Cooperative Extension
1100 Claremont Rd
Carlisle, PA 17015
Office Phone: 7172406500
Virginia Ishler
Extension Associate, Nutrient Management Specialist
The Pennsylvania State University
343 ASI Bldg
Dept of Animal Science
University Park, PA 16802
Office Phone: 8148633912
Dr. John Tooker
Assistant Professor & Extension Agent
Pennsylvania State University
501 ASI Bldg
Dept of Entomology
University Park, PA 16802
Office Phone: 8148651895