The goal of this Agroecosystems project is to develop sustainable dairy cropping systems that minimize environmental impacts and off-farm inputs; and are productive, and profitable. To achieve this, we designed the NESARE Sustainable Dairy Cropping Systems Farm to produce all the forage, feed, and fuel for a 65 cow, 240 acre dairy farm, while conserving soil, nutrients, biodiversity, and energy. In spring 2010, we initiated two diverse, 6-year crop rotations that include legumes, perennials, green manure and cover crops, no-till, and canola, and a straight vegetable oil tractor using farm-scale equipment at 1/20th scale on 12 acres of Penn State’s Agronomy Research Farm. Within each crop rotation we are evaluating innovative management practices to address key issues: i. manure management with shallow-disk manure injection; and ii. weed management with reduced herbicide use, with cultural and mechanical integrated weed management practices. We are also evaluating strategies for canola production, and insect and slug pest management, and included a conventionally managed, corn-soybean rotation on 2 acres for research comparisons. Using the crop yield and quality, and a dairy nutrition model, we simulate the dairy herd’s milk production. To identify system benefits, trade-offs, and opportunities to improve practices, 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 have identified system benefits and opportunities to improve them and new research hypothesis to test. For instance, in the case of the green manure crop comparison and strategy to sustain mycorrhizae in canola, we have gathered multiple performance indicators and can conclude which are most successful. In the winter of 2013 we met with the project Advisory panel and proposed some cropping system changes. Based on the Advisory panel feedback we initiated a number of changes in spring 2013. We have leveraged this project for additional research and education funds, including a AFRI CAP grant and two CIG NRCS grants. The CIG grants have facilitated farmer adoption and on-farm demonstrations of manure injection, cover cropping practices, and the cover crop crimper-roller. We hosted field days in 2011 and 2012, numerous group tours (farmer groups, educators, private sector, students etc.) at the NESARE Sustainable Dairy Cropping Systems Farm. Our team members have presented project results in extension programs, written extension fact sheets, and articles for the regional agricultural newspaper. We also created and maintain a website that links to numerous educational resources, and have helped organize and host an annual research symposium with other cropping systems research projects at PSU.
The Sustainable Cropping System farm objective is to identify how to integrate innovate technology and practices with ecological principles for typical-sized dairy farms in the Northeast and test the hypothesis that a farm can minimize off-farm inputs and rely primarily on natural processes to be both productive and profitable. The design will be based on the following agroecological principles: i) minimize nutrient and soil loss, and build soil organic matter and nutrient pools (via no-till, cover crops, manure injection, legumes) and promote biological processes for nutrient acquisition (legumes, soil biological activity, mycorrhiza), ii) enhance biological diversity and ecological interactions to optimize crop yields and minimize pest outbreaks (ex. crop rotation with diverse crop species and lifecycles, intercrops, and cover crops for weed suppression, disruption of insect movement, and promotion of beneficial insect populations), iii) be energetically efficient and productive (produce oilseed crops for farm fuels, use ecological principles to minimize the off-farm inputs of energy, nutrients, & pest control).
To meet the above agroecological system principles, we will demonstrate and evaluate a number of practices and technologies including: no-tillage or rotational no-till, manure injection, crop rotations and intercrops of perennials, annuals, cover crops, and legumes, a roller-crimper, and a locally produced (New Holland) Straight Vegetable Oil (SVO)-powered tractor. Research indicates that in a well-designed cropping system, these practices can contribute multiple agroecosystem benefits. A number of variations and combinations of these strategies have not however been fully evaluated, particularly in combination in a long-term farming systems experiment. Therefore, for some of the strategies, we will evaluate two variations of the strategies within the crop rotation in a split-plot design. These scientific comparisons will enable us to document system impacts of the options that farmers must chose among. These comparisons are also necessary to more fully understand the fundamental agroecological processes, to share our findings through scientific publications, and to contribute to advancing the science and adoption of sustainable agriculture.
Figure 1 illustrates the three crop rotations and the cropping system practices that we integrated into the manure and weed management strategy comparisons. Crop management details by year such as crop varieties, planting dates, seeding rate and depth, nutrient applications and pest management activities are described in detail in the management tables in the Annual Reports for 2010, 2011 and 2012. For an example, the 2012 management tables are included here with Figure 1.
Each main crop entry plot in the experiment measures 120 feet x 90 feet (27.4 × 36.6 m), and is split into four split-split-plots measuring 90 ft x 30 ft (27.4 × 9.1 m). Plots are surrounded by grass alleyways that separated plots from the others by 30 feet (9.1 m). Each rotation is replicated four times, crop entries within each rotation are arranged in a randomized block design. The soil at the site is predominantly a Murrill channery silt loam, with smaller areas of Buchanan channery loam and Hagerstown silt loam.
In spring 2010, 10 soil cores were collected from random locations in each split-split plot at 0-5 cm and 5-15 cm depth. In spring 2013 this soil sampling was repeated (different # cores). These samples were dried, ground analyzed for pH, soil Carbon, and agronomic soil fertility analysis using Mehlich 3 extraction. Also in spring 2010 and 2013, 5 random soil cores/split-split plot were also collected to 15.24 cm, stored in air-tight containers in a cooler, until they could moist sieved and analyzed for water stable aggregates. In fall 2010 and 2011, 8 soil cores were also collected at 15 cm depth for soil fertility analysis.
Each time liquid dairy manure was applied, a sample was analyzed for nutrient concentration to determine rate of nutrient applications and for nutrient management planning. Pre-sidedress soil nitrate test soil samples were collected when corn was about 12 inches (30.5 cm) tall or before the end of June by collecting three random soil cores/split-split plot to a depth of 12 inches (30.5 cm) when manure was broadcast. Where manure was injected, three samples were collected from random locations within the injected manure band and three from outside of the band. Samples were homogenized, dried and sent to the PSU Soil Analytical Lab for analysis.
Crop yields were collected for each crop entry point in the FORAGE and GRAIN rotation in 2010-2012; data was analyzed with a split-plot, mixed ANOVA model using PROC MIXED of SAS for all crops that received manure or weed management in the rotation. For analysis of split-split plot treatments, such as green manures and canola with or with or without oats, data were analyzed with a split-split plot model. Forage crop yields for all harvests were analyzed with a repeated measures split-plot, PROC MIXED model of SAS.
Crop yields were sampled from the middle of each split-split 90 foot long plots and the sampling width varied with crops. For instance a forage plot harvester sampled the middle 4 feet from the forage crops, while a two row plot harvester samples the middle two rows of corn silage and corn grain, a farm scale combine fitted with a weighing basket harvested the middle 13 feet of canola, soybeans, and wheat. Cover crops and green manure dry matter production was sampled from two 0.5 m2 (5.382 ft2) quadrats per split-split plot. Before cover crop termination, cover crops were sampled for biomass and separated into percent cover crop and weeds. Nutrient analyses were performed on cover crop tissue samples to estimate nitrogen contribution at the time of corn planting. Samples are dried and yields are reported on a dry weight basis.
At every crop harvest in the NESARE Dairy Cropping Systems Trial, we collect three subsamples for forage or feed quality analysis from each of our main management treatments that compare two strategies for either manure in the Forage rotation, or weed management in the Grain rotation. In many cases, processing is needed to prepare a crop sample that is representative of on-farm storage or processing.
Ensiling Forage Crops:
To simulate the fermenting that occurs in the ensiling process, subsamples of forage crops, including alfalfa, alfalfa, grass and companion crop mixtures, corn silage, and red clover, were vacuum sealed and stored at 30 degrees C for at least three weeks to simulate the fermentation that occurs in the ensiling process. The dairy scientist on our team, Virginia Ishler, noted that the forage quality analyses of our simulated silage samples were very similar to the forage quality ensiled at the Penn State Dairy Complex at University Park.
Extracting Oil from Canola:
For canola, we used an Oekotec single-dye press to extract oil from the grain, leaving a high protein meal that can be fed to dairy cows. This “cold” press extraction method can result in a canola meal that has a higher than desired fat content for the dairy ration. We found that drying the canola seed down to 5.5 to 7% moisture before pressing the seed was particularly important in order to maximally extract oil and produce a meal with the lowest amount of fat as possible with the mechanical Kern Kraft press (Fig. 3).
Roasting Soybeans in the Laboratory:
For soybeans, we simulated roasting soybeans by putting raw soybeans in a muffle furnace at 146 degrees C for 30 minutes followed by cooling them in a funnel dryer for 30 minutes. This is the temperature and time period recommended for a commercial roaster by Hsu and Satters, J Dairy Sci., 1995, which we adapted to the laboratory setting. A comparison between three samples each of roasted and raw beans in 2011 revealed that roasting the beans in the laboratory dropped the % soluble protein from 73 % to 21 % (Fig. 4). According to Dairy One Lab’s Feed Composition Library, this is what is expected for roasted soybeans (http://www.dairyone.com/Forage/FeedComp/disclaimer.asp).
Forage and Feed Quality Data Analysis
To compare the main management treatment effects on crop quality we compared a common set of forage and feed quality variables, including % crude protein (CP), % neutral detergent fiber (NDF), and net energy of lactation (NEL/Mcal/lb) and used the same statistical model that we used to analyze crop yields.
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 corn grain, soybeans and canola meal are fed to the herd, as a total mixed ration. Rations for all the animal groups are formulated based on the 2001 NRC model and reflect very closely to what is fed at the Penn State dairy herd. Income over feed costs is monitored monthly for each scenario (BMSH or IMRH) to evaluate the impact of forage quality and quantity on profitability for the lactating cows. A cash flow plan is being developed for each scenario to evaluate the effect on purchased feed costs and how the cost of producing home raised feeds influences the breakeven income over feed costs/cow and breakeven net margin/cwt.
The two treatments were compared primarily in the GRAIN rotation. The “Standard Herbicide” (SH) treatment utilized broadcast herbicide applications to manage weeds in corn grain, soybeans, and alfalfa. The “Reduced Herbicide” (RH) treatment combined banding herbicide, rolling a cover crop with a roller crimper to form a weed-suppressive mat, using a high-residue cultivator for weed control in corn and soybeans; and planting companion crops for weed suppression when establishing an alfalfa-orchardgrass mix (Fig. 1). The SH alfalfa was seeded to only alfalfa as a forage; RH alfalfa was seeded to alfalfa, orchardgrass, triticale (x Triticosecale), and peas (Pisum sativum L.) as forage species. In addition, in the RH treatment, alfalfa was terminated with a moldboard plow before planting canola, while no-till and herbicides were used to terminate alfalfa in the SH treatment (Fig. 1).
To quantify weed severity and treatment effects, weed density and biomass were collected throughout the growing season. Weeds were sampled both from the resident weed population and in 2011 and 2012 from subplots within the crop plots that were supplemented with three weed species (giant foxtail (Setaria faberi Herrm.), smooth pigweed (Amaranthus hybridus L.), and common ragweed (Ambrosia artemiisifolia L.), each at a rate of 1500 seeds per m2, in fall of 2010 and 2011. Weeds in corn grain, soybean, and canola were sampled for density at 4 and 8 weeks after planting, and then for biomass at 12 weeks after planting. Weed density was measured by identifying and counting weeds in two randomly placed 0.7 m2 quadrats from the resident weed population and/or from supplemented weed subplots. Weed biomass was sampled by collecting above-ground weed biomass from two randomly placed 2.48 m2 areas between crop rows from resident weeds (0.7 m2 quadrats in weed subplots), drying the samples at 60°C for at least 48 hours and weighing. For alfalfa, sampling occurred at the time of alfalfa harvest. Weeds in forage crop entry points were quantified by separating aboveground biomass into forage and weeds, weighing dry biomass, and calculating percent composition of each within the forage crop. Weed species were separated by species, and also into four categories by life cycle: annual broadleaf, annual grass, perennial broadleaf, and perennial grass; data was analyzed with a split-plot, mixed ANOVA model using PROC MIXED of SAS.
Within the inject and broadcast manure management treatments, we compared two green manure crops for nitrogen production prior to planting corn silage (Corn silage-Ca). While designed as a comparison between green manure crops, the red clover (RC)-hairy vetch (HV) comparison between winter wheat and corn for silage (Fig. 2), also represents two different weed management systems. Red clover was drilled in one half of the wheat plots in early spring of each year; hairy vetch was planted in the other half 4 to 6 weeks following wheat harvest. The mulch provided by cover crops can suppress weeds during the fall and winter and in the subsequent corn; to lengthen the persistence and improve the weed suppression of the mulch in the HV treatment, triticale was added at 34 kg*ha-1 in mixture beginning in 2011.
The wheat that would be rotated to HV received an early April herbicide application of 0.04 kg*ha-1 Harmony Xtra (thifensulfuron-methyl + tribenuron-methyl). Red clover has the capacity to compete with weeds in wheat and following wheat harvest and herbicide use in wheat could damage RC, so no herbicide was used in the RC wheat. Prior to seeding the HV, a burndown application of 1.26 kg*ha-1 glyphosate plus 0.56 kg*ha-1 2,4-D LVE was applied about 14 days prior to sowing hairy vetch and triticale. Thus, two extra herbicide applications (spring wheat and late summer burndown) were applied to the HV plots that were not needed with RC.
In the forage rotation, weed biomass in wheat was sampled in June before wheat harvest, and weed density and biomass after wheat harvest, but before hairy vetch seeding. Weeds in wheat and in corn silage were sampled both from the resident weed population and from subplots within the crop plots that were supplemented with three weed species (see Grain Rotation Methods) the preceding fall.
Weeds and the cover crops in corn were managed with the preemergence herbicides (glyphosate plus 2,4-DLVE plus dicamba) and with glufosinate postemergence. In 2011, halosulfuron plus nicosulfuron was added to glufosinate for improved yellow nutsedge (Cyperus esculentus L.) and orchardgrass control.
Plot-scale lysimeters were constructed to allow calculation of nutrient balances associated with injected and broadcast (unincorporated) manure applications. Construction of twelve hydrologically-isolated plots (each ~400m2) was completed in the late spring of 2012 on a site overlying shallow bedrock. Drainage tiles were installed in each plot at the level of the bedrock to intercept groundwater flow. Earthen bermes were constructed around each plot to direct surface runoff water to tile outlets. Tiles collecting both surface and ground water from each plot were directed to collection houses. Full instrumentation of the site was finalized in the spring of 2012, including the installation of flumes and pressure transducers in the houses to automate water flow measurement. An automated weather station has been installed, and instrumentation was also added to track soil moisture at 8, 16 and 30 inches in four of the 12 lysimeters. A landscaping project to improve appearances and access for demonstration events was completed in 2012. After observing evidence of bypass flow following the spring manure application, a smoke tracer study was conducted to identify rodent burrows and other macropores that were potentially biasing subsurface runoff monitoring. These macropores were then sealed with bentonite.
In addition to infrastructure for water collection and associated nutrient loss measurements, nitrogen gas flux measurements were made using portable chambers. For nitrous oxide (N2O) measurements, two chambers bases were installed in each plot shortly after manure application. We then sampled twice per week for four to six weeks after manure application, but switched to less frequent sampling as soil dried and N2O emissions diminished. Each time samples were taken, chamber tops were deployed and a series of three samples were taken from each chamber over the course of about 30 min. Samples of ambient air were also taken to establish time 0 baseline. Nitrous oxide concentrations of the samples are determined by gas chromatograph. Emission rates are determined from the slope of the regression of nitrous oxide concentration verse chamber deployment time.
To measure ammonia emissions, were used a 30 x30 x 4 inch chamber (with a fan for air recirculation) in conjunction with a photoacoustic gas monitor. Two or three chamber bases were installed in two replicate plots each of injected and broadcast manure. At each sampling point, we measure immediately after manure application then about 4, 12, and 36 hours after manure application (ammonia emission subside quickly as manure dries).
Both of the FORAGE and GRAIN rotations relied on scouting to manage early season pests and were planted with non-Bt maize varieties. The simple corn-soybean rotation that served as a low-diversity, high-external-input ‘Control’ rotation, was planted with a Bt corn variety, received a pre-emptive application of pyrethroid insecticide in the spring, and was not preceded by a cover crop.
Stand establishment and early season herbivory
To assess maize establishment and damage from early season pests, a three meter stretch of row from the east and west halves of each split-split-plot was randomly selected when maize reached both two and five leaf stages. All samples were taken at least 1.5 m from plot edges. In each sample, the number of maize plants was recorded and each plant was inspected for slug damage, rating them on the following scale: 0: no damage, 1: < 25% leaf area removed, 2: 25-50% leaf area removed, 3: 50-75% leaf area removed, and 4: > 75% leaf area removed (similar to Byers and Calvin 1994). In 2010, a test of this rating system revealed that damage scores of seven independent observers were highly correlated with one another (mean r = 0.86, SD = 0.05). Because slugs feed using a scraping motion, slug damage is distinct from other pest damage, and is also often accompanied by a slime trail that aids in identification. In addition to slug damage, the number of plants severed by cutworms, along with the number of plants damaged by other caterpillars or billbugs.
To measure slug activity-density, square foot pieces of roofing material (made from Owens Corning Rolled Roofing Material, color: Shasta White) as artificial slug shelters were used as shelter traps. While shelter traps provide only a relative measure of slug activity (Byers, Barratt, and Calvin 1989), they are the most feasible sampling method for a large experiment such as this. Starting in mid-April, shelters were randomly placed in the east and west halves of each split-split-plot, at least 1.5 m from plot edges and each other. Shelters were removed to allow for field operations (e.g. manure spreading) but otherwise were left them in the plots continuously. Vegetation or residue was pushed aside so that the shelters laid flat on the soil surface. In 2010, shelters were removed from late June to mid-August during the hottest part of the summer when slug activity on the surface is generally low (Port and Port 1986, Eskelson et al. 2011). In 2011, shelters remained in plots from mid-April to November. Because slugs often leave artificial shelters as they heat up during the day (Hommay et al. 2003), shelters were checked in the morning, with sampling typically completed by noon, and with progressively earlier sampling as temperatures increased through the season. The last sample occurred in each treatment shortly before harvest, in early September for maize grown for silage and in late October for maize grown for grain. Slugs were recorded by species using two references (Chichester and Getz 1973, McDonnell et al. 2009), and voucher specimens of the three species were deposited with the Frost Entomological Museum at the Pennsylvania State University.
European corn borer activity
To assess damage caused by the European corn borer, maize plants were sampled in late August, shortly before silage harvest. We chose this time to capture cumulative damage from first and second generation larvae (Penn State Agronomy Guide 2011). Other demands on the experiment precluded destructive sampling, so we measured evidence of tunneling that was visible on the outside of the stalks and ears (similar to Witmer et al. 2003). In the fourth and eighth row of each split-split-plot, we sampled three sets of two plants spaced roughly 9 m apart for a total of twelve plants sampled per split-split-plot. Each plant was inspected from top to bottom for entrance holes, and we recorded the number of holes per plant.
Predatory arthropod activity-density
We used pitfall traps to measure the influence of treatments on the activity-density of ground-dwelling, predatory arthropods. We placed two traps in the seventh row of each split-split-plot, spaced equally along the row (~ 9 m apart), for a total of eight traps/plot. Each trap comprised a 16-oz plastic deli container (11.5-cm wide, 8-cm tall Reynolds Del Pak ®) that was sunk into the ground so that the edge was level with the soil surface. The lip was removed from an identical container, which was placed inside the first so that it could be easily removed to empty the trap without disturbing the surrounding soil. A white plastic plate (18-cm diameter) supported by nails (8.5-cm long) served as a trap cover and the killing agent was 50% propylene glycol. Traps were opened for 48 h at a time, with the first sample occurring roughly two weeks after corn planting and additional samples about every two and a half weeks until early September (maize silage harvest). The two samples from each split-split-plot were combined into one sample, strained through a fine mesh sieve (1-mm openings) and then transferred into 80% ethanol for later identification. Predatory arthropods were identified to the lowest level possible, mostly to family except for Carabidae which were identified to species or genus. We identified carabid species using a regional publication (Bousquet 2010) and a reference collection at the Pennsylvania State University from previous studies of carabids in central Pennsylvania (Leslie et al. 2007, 2009). Other arthropods were identified with trusted references (Kaston et al. 1972, Triplehorn and Johnson 2005, and Ubick et al. 2009). Voucher specimens of carabids and other arthropods identified in this study have been deposited with the Frost Entomological Museum at the Pennsylvania State University.
Predation on sentinel caterpillars
In 2011, we used sentinel waxworm caterpillars (Galleria mellonella) to assess predation (after Lundgren et al. 2006). Once in June (6/14/11) and again in July (7/21/11), I deployed eight caterpillars along the eighth row of each split-split-plot. We pinned caterpillars (mean mass: 0.20g, SD: 0.04g) through their final abdominal segment to a small piece of modeling clay that was buried in the field so that the caterpillar rested on the soil surface. In initial laboratory and field experiments, caterpillars survived in this condition for over 24 hours. Every other caterpillar was enclosed in a cylindrical, hardware cloth cage (9.5-cm tall, 11.5-cm diameter, mesh size: 1.3 cm) topped with a plastic lid to exclude vertebrates. On each sample date, I made two assessments of predator activity: one started at 8:30, and the other at 20:30. Sentinel caterpillars were checked 3 and 12 h after being placed in the fields. After 12 h, any caterpillars that had been attacked or were missing or compromised were replaced with new caterpillars. During night-time sampling, observers used red headlamps or lights covered in red cellophane to minimize disturbance to predators. We recorded caterpillars as whole and alive, partially eaten, or missing at each time point. Caterpillars that died but showed no signs of predation were recorded and excluded from the analysis. In addition, observers recorded the presence of predators in proximity to or eating the caterpillars.
We implemented scouting protocols to guide IPM decision-making for key pest species including potato leafhopper in alfalfa and early-season pest species attacking corn and the later-occurring European corn borer. For instance, leaf hopper populations were sampled weekly in alfalfa and alfalfa mixture stands using a standard sweep net approach at the split-plot level. Management decisions to cut or spray stands were based on whether populations had surpassed economic thresholds or not (based on recommendations in Penn State’s Agronomy Guide). Stand counts and damage assessments were implemented in corn at V2 and V5 stages to monitor early season pests, while evidence for corn borer damage was assessed prior to corn harvest each fall.
To understand the influence of treatments on pests and predatory invertebrates, we compared response variables using linear mixed models (PROC MIXED; SAS 9.2, SAS Institute Inc. 2009) for all analyses unless otherwise stated. To improve their relevance or satisfy assumptions of normality and homoscedasticity, we transformed some of the data prior to analysis. For stand establishment, we converted the number of maize seedlings per sample at V5 into plants per acre, and then divided by the seeding rate for each treatment to calculate establishment as a percentage of the number of seeds planted. Pitfall trap catches were totaled over the season to compare cumulative predator activity-density in the different treatments. For Carabidae, we separately analyzed species that made up more than one percent of the total carabid catch in each year. Slug counts, European corn borer damage, and pitfall trap catches were square-root transformed.
We used three models to examine the influence of experimental treatments on response variables. For variables with a single measurement (maize establishment, European corn borer damage, seasonal pitfall trap catches), we used a model with block as a random factor, rotation as a fixed factor, and weed or manure split-plot treatment as a fixed factor nested within rotation. Because only the Forage rotation included split-split-plot treatments, we performed a separate analysis for this rotation, with block as a random factor, manure split-plot treatment as a fixed factor, and cover crop split-split-plot treatment as a fixed factor. Where the analysis indicated a significant treatment effect (P ? 0.05), I used Tukey’s post-hoc tests to separate means.
For response variables that were measured at multiple times (slug damage at V2 and V5, slug activity-density over the season), we used repeated measures analyses. The model was similar to that described above, but also included date and its interactions with block, rotation, and split-plot as within-subject factors. We evaluated candidate covariance structures for each response variable and selected an appropriate covariance structure by minimizing AICC scores (Wang and Goonewardene 2004, Littell et al. 2006). This resulted in using the variance components covariance structure for both slug damage and slug activity-density. Where the analysis indicated a significant date by treatment effect, I used the ESTIMATE procedure to separate means within dates (Littell et al. 2006).
The analysis of predation on sentinel caterpillars included several additional variables that necessitated a unique repeated measures analysis. The model included block as a random factor, rotation as a fixed factor, and weed or manure split-plot treatments as a fixed factor nested within rotation. In addition, cage treatment (caged or open) was included as a fixed factor, along with its interactions with the other factors. The repeated factor was time of day (day vs. night).
To examine whether slug activity-density measured via shelter traps was related to slug damage to corn seedlings, we used correlation. We averaged values of slug activity-density collected in spring (April to June) for each plot, and then related activity-density to mean slug damage scores using Pearson’s correlation (Minitab v. 16, Minitab, Inc., State College, PA). Because of differences in the timing of field operations each year, the spring average represented three sample dates in 2010 and nine sample dates in 2011.
We used a similar approach to examine whether predator activity-density measured via pitfall traps was correlated with predation on sentinel caterpillars under vertebrate exclusion cages in 2011. Because of low predation in June, this analysis was restricted to July (sentinel prey sample: 7/20/11; pitfall sample: 7/21/11-7/23/11). We used field observations of predation on tethered caterpillars to choose taxa that would be expected to correlate with predation. The taxonomic groups tested in the analysis included ants (Formicidae), the dominant ground beetle Pterostichus melanarius, all large Carabidae (? 9mm), and all predatory arthropods combined. We used Pearson’s correlation (Minitab v. 16) to test for a significant relationship between catches of these taxa and caterpillar predation as observed three and twelve hours after the start of the experiment. Both variables were averaged at the plot level.
In order to compare rotation effects on arbuscual mycorrhizal fungi, fungal colonization assessments were made on corn seedlings following different cover crops in the NESARE diary cropping systems, 10-14 days after emergence (or late V1) by clearing and staining corn roots and looking for mycorrhizal fungal structures. Additionally, data on corn seedling aboveground biomass and %N and %P in the aboveground tissues were obtained.
Similarly, in alfalfa and canola split plots in the GRAIN Rotation, corn seedlings were planted into the crops and used as trap seedlings to assess mycorrhizal colonization, aboveground biomass, and %N and %P in the aboveground tissues as described above.
NESARE Dairy Cropping Systems Research Site
For the most part, farm management practices were implemented as planned for our dairy cropping systems (Project Schematic Figure 1 in Methods). In 2011, however, unusually wet weather in spring (10.35 inches in April and May) and early fall (5.62 inches in August) delayed spring operations and delayed or prevented some fall field operations. In 2012, March was unseasonably warm, followed by dry weather, spring frost, and then wet spring weather in spring and in fall which delayed some fall field operations. Details about challenges with crop operations can be found in the sections on yields for the Forage and Grain rotations. Figure 2 through Figure 22 and Table 1-22 referred to in this section are available by the same titles in the 2012 Annual Project report and should be accessed there.
Forage Rotation: Yields
In 2012, the effect of manure management on crop yields across the rotation was significant (p = 0.0360; Table 1, in 2012 Annual Report ), although this was not significant in 2011 or 2010. This significance of manure management in 2012 at the rotation level appears to be a combination effect. The three individual pre-planned contrasts for each of the corn silage and canola crop entries however were not significant. Yield of the two corn silage entries with injected manure only tended to yield 9% more than the corn silage with broadcast manure (p values = 0.09 and 0.12). By contrast, the canola yield with the injected manure (IM) tended to yield less than the broadcast manure treatment (p =0.07). Over the years, we have observed inconsistent canola populations in the injected manure treatment that we suspect is due to the difficulty of using the no-till drill to plant canola at a shallow depth (~ 1/8 to ½ inch) into the uneven micro-topography created by the manure injection operations. In 2012, a John Deere no-till drill was purchased through collaboration with many researchers. It is reputed to have better seed depth control particularly into residue and we plan to use this no-till drill to plant canola in 2013.
For the corn crop entry points, in 2010 and 2012, the pre-sidedress nitrogen tests indicated that less sidedress nitrogen was needed where manure had been injected (Table 2, in 2012 Annual Report). By 2012, little or no sidedress nitrogen was needed following a green manure or perennial legume crop compared to rye, no cover crop, and in the first year of the project (Table 2). In 2010, rye preceded all corn crops and we applied less manure to our corn crops because we thought the farm could support fewer cows than in 2012. Nonetheless, considering that each unit of manure solids comprises ~0.5% nitrogen, the slightly higher manure rate in 2012 does not explain the large drop in the need for sidedress nitrogen. Likely, the legumes in combination with manure injection are increasing soil nitrogen pools and reducing or eliminating the need for sidedress nitrogen applications.
Due to the unusually wet spring and fall weather in 2011, the corn silage that follows red clover and hairy vetch was planted later than intended (FORAGE rotation; Fig. 1) and harvest in 2011 of this short-season corn silage hybrid was further delayed by rainy fall weather. As a result, winter canola was not planted after the corn silage. Because our virtual dairy farm needed to empty its manure storage facility prior to winter, we injected and broadcast the manure treatments, planted winter rye in the fall 2011, and spring canola in 2012. In fall 2012, wet weather again delayed corn silage harvest, winter canola was not planted, and winter rye was planted instead after manure treatments were applied. In spring 2013, we will terminate the winter rye early and plant spring canola.
Also, in 2010 and 2011, the alfalfa and orchard grass planted in late summer after canola in the FORAGE Rotation failed to establish and although canola residue allelopathy may have contributed, high slug activity also appears to explain the poor seedling establishment. After these observations, our advisory panel farmers explained that due to slug pressure, they prefer to plant no-till alfalfa in early spring rather than late summer. The alfalfa and orchardgrass were replanted in spring 2011 and 2012 and established successfully in spring 2011. In spring of 2012, replanted alfalfa and orchardgrass failed to establish twice, so we planted an emergency crop of BMR sorghum sudangrass which established well and provided two forage harvests (see Table 3, in 2012 Annual Report). These repeated challenges in establishing winter canola after corn silage and alfalfa and orchard grass after canola has convinced the team to reorganize the FORAGE rotation. Rather than planting winter canola after corn silage, we will plant winter wheat after corn silage and then canola will follow winter wheat when if it can be planted ear
We created a project website (see: http://plantscience.psu.edu/research/areas/crop-ecology-and-management/cropping-systems) that includes links to educational resources about the innovative practices. In 2011 and 2012, we hosted field days; in 2012 we collaborated with two other cropping system projects, ROSE and OREI-CC, to engage participants with hands-on activities and field demonstrations. At both field days we asked participants to complete a short questionnaire and in both years, 98% of the individuals who complete the questionnaire rated the tours as good to excellent (See evaluation forms, Figures 3 and 4). In 2011, Ninety-three percent of those responding to the farmer panel discussion indicated that this activity was of good-to-excellent value to them. During the tours, presenters emphasized the sustainable agriculture concepts and practices that we are evaluating, to increase attendees’ knowledge and the evaluations indicated that for many of the concepts, we succeeded. For instance in 2012, knowledge increased for participants at all 5 stations with a 15% increase for “Improving Manure Management”, a 26% increase for “Nitrogen Supply from cover crop mixtures”, a 34% increase for “Strategies to integrate cover crops and their characteristics”, a 52% increase for “The relationship between a cover crop’s C:N ratio & its persistence”, and a 64% increase for “The value of predators for pest control & ways to increase predator activity”.
Our team members have also integrated the project research results into extension programs, project extension bulletins, newsletters and agricultural newspaper articles.
- Malcolm, G.M., Karsten, H.,D. Beegle, W. Curran, C. Dell. P. Kleinman, T. Richard, V. Ishler, J Tooker and R. Hoover. 2011. Evaluating Dairy Cropping Systems Designed to Produce All Forage, Feed, and Fuel. Annual ASA, CSSA, SSSA Meetings. Oct. 16-19, 2011. San Antonio, TX. Abstract # 65526. Karsten, H.D., Organic Crop Rotation Design. In press. The Organic Agronomy Guide. The Pennsylvania State University. Canola and Energy Management Team: Karsten, H.D., W.Verbeten, G. Malcolm, M. Douglas and J. Tooker. 2012. No-till Establishment of Alfalfa and Canola and Slug Herbivory. Proc. Amer. Soc. Agron. 337-25. Malcolm, G. M., G. Camargo, T.L. Richard and H. Karsten. 2012. Energetic Analysis of a Diverse Dairy Operation, Producing Fuel, Feed, and Forage As Compared to a Typical Dairy Operation of the Same Size. Proc. Amer. Soc. Agron. 187-11. Malcolm, G., G. Camargo, T.L. Richard, V. Ishler, and H. Karsten. 2012. Energetic Analysis of Dairy Cropping Systems That Use Straight Vegetable Oil Fuel Grown On Farm. Pennsylvania State University Post-doctoral Research Exposition. Karsten, H.D., G. M. Malcolm, D. Beegle, W. Curran, C. Dell. P. Kleinman, T. Richard, V. Ishler, J Tooker and R. Hoover. 2011. Integrating Winter Canola Into Dairy Crop Rotations. Annual ASA, CSSA, SSSA Meetings. Oct. 16-19, 2011. San Antonio, TX. Abstract # 65533. Insect/Slug Management Team: Douglas, M. R., and John F. Tooker. Insights on the ecology and management of slugs in Pennsylvania no-till crop fields. Annual Meeting of the American Malacological Society, Cherry Hill, NJ, 18 June 2012 Manure Management Team: Duncan, E., P. Kleinman, C. Dell, D. Beegle, and H. Karsten. 2011. Improving manure management to balance nitrogen use efficiency and environmental trade-offs. Proc. Soil Sci. Soc. Am. 151-11. Duncan, E. 2011. Nutrient Cycling Trade-offs Associated With Different Manure Management Strategies. Soil and Water Conservation Society Annual Meeting. Weed Management Team: Curran W. and D. Lingenfelter. 2012. Exploring opportunities to diversify burndown options in no-till crop production systems. Proc. Northeast Weed Sci. 66. Curran, W. and D. Lingenfelter. 2012. Challenges to diversifying herbicide options in continuous no-till production systems. Abstr. WSSA 56:346. Keene, C.L. and W.S. Curran. 2012. Effectiveness of shallow high residue cultivation in no-till soybean. Proc. Northeast Weed Sci. Soc. 66. Snyder, E., H. Karsten, W. Curran and G. Malcolm 2012. Reducing herbicide use in a no-till dairy cropping system. Proc. Amer. Soc. Agron. 200-9. Snyder, E.M. 2012. Reducing Herbicide Use in a No-Till Dairy Cropping System. Gamma Sigma Delta Student Poster Exhibition, March 2012, University Park, PA. Snyder, E.M., W.S. Curran, H.D. Karsten, and G.M. Malcolm. 2012. Reducing Herbicide Use in a No-Till Dairy Cropping System. International Soil Tillage Research Organization Conference, Montevideo Uruguay. Snyder, E.M., W.S. Curran, H.D. Karsten, and G.M. Malcolm. 2012. Evaluating integrated weed management for no-till dairy cropping systems. Proc. Northeast Weed Sci. Soc. 66. Insects & Slugs Team: Douglas, M. and J. Tooker. 2012. Slug (Mollusca: Agriolimacidae, Arionidae) ecology and management in no-till field crops, with an emphasis on the mid-Atlantic region. Journal of Integrated Pest Management. Volume 3, Number 1, 2012 , pp. C1-C9. Other Scientific Presentations: Karsten. H. D. 2011. Investigating Strategies for Sustainable Cropping Systems. Rutgers University Department of Plant Biology and Plant Pathology Spring Seminar Series & Graduate Course. March 4, 2011 Karsten. H. D. 2011. Investigating Strategies for Sustainable Cropping Systems. Horticulture Dept. Penn State University Spring Seminar Series. March 30, 2011 Malcolm, G.M. and Karsten, H.D. 2011. Sustainable dairy cropping systems to produce forage, feed, and fuel. Post-doctoral Research Exposition, April 12, 2011. Penn State University. Tooker, J. and M. Douglas. 2011. Research update on slugs in Pennsylvania. Northeastern IPM Center’s High Residue Cropping Systems IPM Working Group, August 2011, Newark, DE.
Our 2009 CIG NRCS project is described on a webpage linked to our NESARE Sustainable Dairy Cropping Systems project website. The website provides information about the four cooperating commercial manure haulers and county extension educators on a series of webpages (See: http://extension.psu.edu/plants/crops/cropping-systems). With the NRCS CIG funds we created internet links to an alphabetically ordered list of extension publications on the sustainable agriculture practices employed in our cropping systems and other relevant information. We also created a webpage with links to short videos of the cooperating farms employing shallow-disk manure injection and the cover crop roller-crimper.
Additional videos are being created by a videographer and the cooperative extension educators with funds from a 2010 CIG NRCS grant that is demonstrate manure injection and cover crop mixtures on farms in multiple counties, and involves working with farmer networks to promote adoption of conservation practices.
Additional Project Outcomes
Impacts of Results/Outcomes
Based on the results of 2010-2012, we developed and proposed a number of cropping system changes to the Advisory panel in March 2013. We integrated the feedback of our Advisory panel and in spring 2013, we initiated a number of changes that are illustrated in Figure 2. We changed the names of the two rotations to reflect the management practices that we are comparing. What was formerly called the GRAIN rotation is now the PEST management rotation and the former FORAGE rotation is now the MANURE management rotation. The rationale and each change that we made described below:
- 1. To further reducer herbicide applications, in RH (reduced herbicide treatment) in the PEST management rotation, we will not spray herbicides prior to planting the cereal rye cover crop after winter canola and soybeans, unless scouting in late summer indicates that weeds will hinder the establishment of the rye cover crop. Further, after winter canola is harvested, we expect winter canola seedlings will volunteer, and as recommended by the Advisory panel we will evaluate if we can manage the volunteer canola to establish a cover crop mixture. In the RH treatment we will mow the volunteer canola prior to planting cereal rye to establish a cover crop mixture, versus in the SH treatment we will terminate the canola with an herbicide prior to planting rye. 2. In the PEST management rotation, in 2011 and 2012, we have found that soybean establishment and yields were hindered in both RH and SH by the rye cover crop residue, no-till planting equipment complications associated with the cover crop residue and associated high soil moisture, and slug activity (see Results discussion). To address these challenges, we will terminate the rye cover crop in the RH treatment earlier than we had in 2010-2012 with an herbicide (when it is 10-15 inches prior to boot stage) and plant soybeans in both the RH and SH treatments with a no-till planter rather than a no-till drill that was used in the SH treatment. To assess if row spacing, is contributing to lower crop yields we have split the SH treatment into split-split plots of 15 and 30 inch rows. 3. Although the high-residue cultivation in the corn and soybean row crops has been relatively effective for controlling weeds between the crop rows, farmer members of the Advisory panel noted that the majority of no-till farmers would not adopt cultivation. Therefore, in the corn and soybean crops in the RH treatment of the PEST management rotation, we have included split-split plots to compare the post-emergent weed control strategies: i. the high residue cultivator versus ii. post-emergent broadcast herbicide application to represent no-till crop management practices. 4. Through IPM practices, in the alfalfa and alfalfa and orchardgrass crops, we were able to limit insecticide applications in 2010-2012 to only one application/season to control potato leafhopper (PLH). To expand our IPM strategies, we will evaluate PLH-resistant alfalfa in both rotations. In spring 2013, we planted a PLH-resistant alfalfa variety in the RH treatment of the PEST rotation and the IM treatment of the MANURE rotation to a similar alfalfa variety to alfalfa that is not PLH resistant in the SH (PEST rotation) and BM (MANURE rotation) treatments. 5. After two years of failed no-till alfalfa and alfalfa and orchardgrass establishment in late summer when slug herbivory is elevated, we have moved no-till alfalfa and orchardgrass planting in the PEST rotation to spring. We will plant oats after corn silage winter-kill to create a good seed bed for spring planting of the forages a recommendation of the Advisory panel. To allow time to plant oats prior to the forages, we have substituted corn silage for the previous corn grain in the PEST rotation and will plant corn grain the MANURE rotation. 6. To establish a cover crop in corn grain in the MANURE rotation, we will use the Penn State cover crop interseeder to plant annual ryegrass and a clover mixture inbetween the corn grain rows when nitrogen is side-dressed. To take advantage of these cover crops and because annual ryegrass termination is often not successful in April, we are following this cover crop interseeded corn grain with corn silage, rather than spring forage crop establishment. This is the other reason that the corn grain was moved to the MANURE rotation. 7. In 2010, we realized that we could feed 65 cows rather than 60 cows and likely still have extra perennial forage crops. However, as discussed in the results section, in 2011 and 2012, unusually wet springs and summer drought stress limited corn production, and we realized that in most years the dairy herd requires another crop entry of corn silage. In good years, some of additional 20 acres of corn could be harvested for additional corn grain. Therefore, we decided to eliminate the winter wheat in the forage rotation and replace it with corn silage. Although the dairy farm used the wheat straw for bedding, we did not need the winter wheat grain for feed; it was sold off the farm. 8. In the FORAGE rotation, we tried to plant winter canola after corn silage, but in two out of three years (2011 and 2012), wet fall weather delayed corn silage harvest and late planted winter canola likely would not have established well and would had been subject to high slug herbivory. Therefore, we applied manure (inject or broadcast), planted a cereal rye cover crop and then spring canola the subsequent spring. Therefore, in the MANURE management rotation, we plan to continue to spring canola after a rye cover crop planted after corn silage-rye. 9. In 2010-2012, we found that red clover provided multiple benefits over hairy vetch and triticale (see Results for more details) and concluded that we should not continue the green manure comparison of hairy vetch and triticale to red clover. And to produce sufficient forage for the dairy herd, in the MANURE management rotation, we replaced the winter wheat with corn silage. Others however, have successfully planted red clover with spring canola, and we are interested evaluating this intercrop system because the red clover could help to sustain mycorrhizal fungi in the non-mycorrhizal canola crop, produce enough forage for a fall harvest, while providing some green manure prior to planting corn silage the following spring. We are also interested in evaluating crimson clover as a green manure crop, because farmers grow it as a green manure crop and John Tooker (project Entomologist) observed that crop crimson clover reduced slug activity in one study. The Advisory panel was supported this new green manure comparison. In the MANURE rotation, we will compare red clover planted with spring canola to crimson clover planted after spring canola within both the inject and broadcast manure treatments (split-split plots).
Project members Tim Beck (Farm Finance Cooperative Extension) and Virginia Ishler (Dairy Science) have taken the lead in comparing the economic performance of the NESARE Sustainable Dairy Cropping Systems Farm to benchmark Pennsylvania dairy farms that they work with. Compared to the common practice of growing forage crops on–farm and purchasing grain from off farm, the NESARE Sustainable Dairy Cropping Systems Farm has demonstrated that Pennsylvania dairy farms can significantly reduce their feed costs ($200 on average in 2010-2012) and improve their nutrient management by producing all or most of the dairy’s grain and forage crops on-farm. Our project has demonstrated that double-cropping winter annual crops such as winter wheat, winter rye, and winter canola; and integrating corn, soybean and canola grain production the NESARE Sustainable Dairy Cropping Systems Farm has improved nutrient management and farm profitability. In 2012, project members Virginia Ishler and Tim Beck worked with farmers to gather additional farm management records and economic performance data to further document this double-cropping benefit on commercial farms. With team member Ron Hoover (on-Farm Research Coordinator) they developed and presented educational programs to promote double-cropping winter annuals with corn silage and sorghum-sudangrass forages to increase production of on-farm feed and forages, enhance crop production flexibility, and provide soil, nutrient, and economic benefits. Although we are still monitoring the impacts, we anticipate that these results and educational outreach activities will increase farmer adoption of double-cropping and increased on-farm feed and forage production.
Conservation practices in our project have been demonstrated for three years on multiple farms through our Natural Resource Conservation Service (NRCS) Conservation Innovation Grant (CIG) that was funded in summer of 2009. Practices that farmers were most interested to try were shallow- disk manure injection in no-till cropping systems and the cover-crop roller to manage tall cover crops and create a high residue mulch. With funds from the 2009 CIG NRCS grant, shallow-disk manure injection equipment was purchased for four manure haulers to use on cooperating demonstration farms and to promote manure injection on additional farms. Two cover-crop roller crimpers were also purchased for farmers in two counties. The manure haulers in three counties have helped to demonstrate and promote shallow disk injection adoption on many farms, and they report that they are injecting millions of gallons manure on a number farms in Pennsylvania and in some locations in Maryland. The cover crop roller crimper has been adopted for regular use by one farmer. Field days were hosted at the Penn State Landisville Research farm in Lancaster PA and farms in all four counties.
Due to the challenges of a shorter growing season, very wet weather and operator limitations, the manure injection equipment was not used in in the fourth northern location (Bradford County) and a no-cost extension of the grant was approved for 2013. In spring 2013, it was moved to a commercial manure hauler located in an impaired, EPA-targeted watershed in Mifflin and Juniata Counties where farmers have expressed an interest in manure injection in Central PA. We are assisting with on-farm demonstrations and working with colleagues from Penn State Dairy and Animal Science to promote adoption. We are also in the process of identifying a location to relocate the cover crop roller crimper.
Based on feedback at our 2011 and 2012 field days (see Publications/Outreach), a number of farmers have indicated that they are planning to integrate or adopt a number of the conservation practices that we featured at our field days. After we have summarized the first four years of the cropping systems performance and shared the results through additional presentations and publications, we will conduct more surveys and assess outcomes.
Areas needing additional study
We identified a number of cropping system research needs, and we have integrated many of these research questions into the revision of our cropping systems research that we initiated in 2013 (see Impact of Results/Outcomes section of this report).
In addition, we learned that cover crop residues can significantly reduce no-till crop establishment and crop yields. Through our research and consulting with our Advisory panel, we have an improved understanding of how cover crop residue, soil moisture, planting equipment complications and slug activity can reduce crop establishment and yield. In 2013, we developed a NESARE Research and Education grant proposal to evaluate management practices that can likely address these cover crop termination challenges while optimizing cover crop benefits and improving no-till crop establishment.
Through the CAP AFRI grant, in 2013 we also began quantifying nitrous oxide emissions from three different legumes prior to corn planting with and without manure.