Final Report for LS06-189
Project Information
A three-year study in Oklahoma and Texas revealed that no-till wheat is a viable option for Southern Great Plains’ farmers and ranchers. Grain yield of no-till wheat plots were comparable to those of conventional-till plots, but fall forage yields were consistently lower in the no-till plots. Aphid numbers were lower in no-till wheat plots while Hessian fly numbers were higher than those in conventional till plots. Overall our research and extension efforts have resulted in increased acceptance of no-till production methods in integrated crop-livestock systems in the Southern Great Plains.
Our long-tem objective is to increase the sustainability of farming and ranching operations in the southern Great Plains by increasing the adoption of no-tillage production practices and decreasing the reliance on commercial fertilizer sources. This project will move us closer to this long-term goal by addressing the following objectives:
1. Determine the impact of switching from conventional to no-till production practices on fall forage production and yield components of winter wheat in grain-only and dual-purpose wheat production systems.
2. Monitor the incidence and severity of wheat diseases as well as the presence and abundance of insect pests and their natural enemies in conventional and no-till, dual-purpose wheat production systems.
3. Determine if sensor-based nitrogen recommendations developed for conventional tillage systems are valid in no-tillage, dual-purpose wheat production systems.
4. Determine the economics of no-till versus conventional tillage for dual-purpose wheat under both conventional fall nitrogen application with rates based upon yield goals and field-specific spring nitrogen application with rates based upon yield potential as measured in late winter by optical reflectance technology.
5. Educate southern Great Plains wheat producers on how no-tillage production practices can enhance both grain-only and wheat/stocker-cattle integrated production systems.
The purpose of this project is to move the wheat and wheat/stocker cattle integrated production systems in the southern Great Plains closer to sustainability by investigating the effect of no-tillage cropping systems on wheat insect presence and abundance, wheat disease incidence and severity, wheat grain yield components, wheat nitrogen requirement, and system profitability. We propose to accomplish this task by conducting research to evaluate the impact of no-till practices on wheat insect presence and abundance, wheat disease incidence and severity, wheat yield components, fall forage production and yield of hard red winter wheat, the validity of sensor-based nitrogen recommendations in a no-till wheat production system, and impact on overall system profitability. Further we propose to increase the education and awareness of sustainable agricultural systems among southern Great Plains’ farmers through development of research-based extension and education efforts in regards to no-till wheat production in the southern Great Plains.
Agriculture in the southern Great Plains.
Production agriculture in the southern Great Plains is dominated by continuous hard red winter wheat production, and farmers typically rely upon low production costs rather than high yield to generate profit. In response to low profit margins associated with grain-only wheat production systems, many wheat producers choose to integrate a stocker-cattle production enterprise into their wheat production efforts (i.e. a dual-purpose wheat production system). In this system wheat is planted at high seeding rates (> 120 kg ha-1) in late-August and early-September. This methodology typically provides enough vegetative growth to allow winter grazing for 150 – 200 kg stocker cattle. If livestock are removed before the first hollow stem stage of growth (Feb. 20 to March 1 most years), wheat will mature and produce a grain crop for harvest in June.
Problem 1. Reluctance to adopt no-till production practices
Reasons for not adopting no-till production technologies include a lack of sufficient research with modern equipment and crop rotational options, comfort and security associated with using traditional seedbed preparation techniques, and the unwillingness of older producers to adopt new farming techniques (CTIC 2004). These are especially true in the southern Great Plains where less than 5% of agricultural producers use no-till planting methods and less than 20% use conservation tillage practices (Ali 2002). Furthermore, inconsistency yield comparison results for no-till vs. conventional till (Sow et al. 1998; Unger 1994) sends mixed messages to producers and certainly does not aid in the promotion of no-till production. We have learned through one-on-one discussion with producers and question and answer sessions at grower meetings that farmers in the southern Great Plains are interested in switching to no-till production practices but cite poor equipment performance, increased disease and insect pressures, uneasiness about possible impacts on wheat forage production and grazing, and lack of university-generated management guidelines as reasons for not switching to no-till production systems.
Previous research has indicated that savings from reduced machinery, labor, tractor fuel, and repair costs associated with no-till production practices were more than offset by increased herbicide cost (Epplin et al. 1983). However, the price of glyphosate (four pounds of emulsifiable concentrate per gallon) has declined from a U.S. average of $45.50 per gallon in 1999 to $20 per gallon in 2005, thus reducing by more than half the cost of herbicidal control of summer weeds from harvest in June until planting in September. In contrast, oil prices now exceed $65 a barrel and farm diesel prices have doubled. Further, increased fuel costs would have greater effect on farmers in the southern Great Plains, as an average of 46 L ha-1 of diesel is used to produce a wheat crop as compared to 32 L ha-1 in the northern Great Plains and 27 L ha-1 in the north central US (Ali 2002). Higher fuel costs are the direct result of the average 3 heavy tillage operations (plowing and disking) used to produce wheat in the southern Great Plains as compared to 1.3 in the northern Great Plains. At current fuel prices, reducing the average fuel expenditure from 46 L ha-1 to 32 L ha-1 would result in a $24.3 million net reduction in production costs in Oklahoma alone. In other words, we feel that by switching to no-till, farmers will be essentially trading high-priced, conventional production practices with high environmental impact (e.g. tractor engine emissions, fuel consumption, carbon loss and erosion from tillage operations, etc.) for low-priced, low-environmental-impact production practices, thus resulting in a huge step towards long-term sustainability.
Problem 2. Insects and conventional wheat production
Wheat producers in the Southern Plains are regularly faced with insect and weed pressures primarily in the form of aphids and grassy weeds (Kelsey and Mariger 2003, Keenan et al. 2005). Two of the most common insect pests of winter wheat in the Southern Region are the greenbug (Schizaphis graminum Rondani), and the bird-cherry oat aphid (BCOA, Rhopalosiphum padi L.). When greenbugs and BCOA surpass economic injury levels (EIL's) in wheat, plant growth is inhibited, which reduces yields and net profits (Burton et al. 1985, Kieckhefer and Kantack 1988, Webster 1995, Riedell et al. 1999, Kindler et al. 2002). Although the degree of injury to wheat differs significantly between greenbug and BCOA, resulting damage levels are quite similar (K.L. Giles, Unpublished Data). In fact, Oklahoma farmers can suffer annual losses attributed to aphid pests can reach $135 million (Starks and Burton 1977, Wratten et al. 1990, Webster 1995).
Much of winter wheat in the Southern Plains is grown conventionally either continuously or followed by a year of fallow in semi-arid locales (Royer & Krenzer 2000), however, very few acres are devoted to no-till. From an ecological standpoint, conventional wheat monoculture habitats increase reliance on insecticide-based management by attracting aphids to wheat and likely decreasing the presence and effectiveness of predators and parasitoids (Andow 1983, Burton and Krenzer, 1985, Burton et al. 1987, Way 1988, Andow 1991, Elliott et al. 1998b, French and Elliott 1999, Brewer et al. 2001, French et al. 2001, Elliot et al. 2002, Giles et al. 2003). Researchers (Burton and Krenzer 1985, and Burton et al. 1987) have demonstrated that greenbug are less likely to colonize reduced tillage wheat systems and their resulting numbers are less damaging to wheat. It is believed that greenbugs are not attracted to more diverse no-till habitats (wheat with previous vegetation stubble) likely because crop reflectance patterns are disrupted and the habitat is viewed as less suitable. Currently, however, there is no information on the effect of reduced tillage on other aphid species (primarily BCOA) and additional arthropod pests.
There is a long list of studies demonstrating that insect predators and parasitoids are conserved and more effective in diversified less-disrupted agricultural systems (Andow 1983, Burton and Krenzer, 1985, Burton et al. 1987, Way 1988, Andow 1991, Elliott et al. 1998b, French and Elliott 1999, Brewer et al. 2001, French et al. 2001, Elliot et al. 2002, Brewer and Elliott 2004). In reduced tillage cropping systems other than wheat, natural enemies of pests are able to persist in these non-disrupted habitats and maintain pests below economically damaging levels. To date in the Southern Plains, however, there is no quantitative information on how reduced tillage wheat systems influence the abundance and effectiveness of aphid predators and parasitoids. In summary, it is not known how no-till production systems will impact the pest / natural enemy balance in a monoculture, dual-purpose wheat production program.
Problem 3. Tradition-based fertilization practices
A major input cost for wheat production and major potential environmental contaminant is nitrogen fertilizer. In the southern Great Plains, the majority of wheat fertilizer is applied pre-plant using either urea (46-0-0) or anhydrous ammonia (82-0-0) as the N source. This method is generally preferred by farmers because of the ability to use farmer-owned equipment and the belief that large amounts of N are needed to ensure adequate wheat-forage production for grazing by stocker cattle. The general recommendation is that farmers apply 0.033 kg N ha-1 per kilogram of yield goal (i.e. 2 lb. of N per bushel of yield goal). For example, a farmer with a yield goal of 2,700 kg ha-1 (40 bu/ac) would apply 90 kg N ha-1 (80 lb. N ac-1), minus any nitrogen already present in the soil, as determined by soil test. In addition, farmers utilizing wheat for both pasture and grain (i.e. dual-purpose) must estimate the amount of N removed through the grazing process and supplement by spring nitrogen application at the rate of 34 kg N ha-1 (30 lb ac-1) for every 112 kg ha-1 (100 lb ac-1) of beef weight gain. One of the primary flaws with this methodology is that the wheat producer must make decisions about crop N requirement before the first seed enters the soil. Furthermore, even though annual soil testing is recommended, most of these producers are making N application decisions without the aid of a recent soil test, making the typical fertilization practice in the southern Great Plains a tradition-based rather than research-based decision.
Use of tradition-based fertilization practices results in approximately 65% of applied nitrogen fertilizer being lost to volatilization and leaching (Johnson and Raun, 2003). Since commercial fertilizer production relies on fossil fuels, this is tantamount to losing the production of 15 gas wells, each producing 1 million cubic feet of natural gas per day! As a result, average losses to Oklahoma farmers from poor nitrogen use efficiency of wheat exceed $85,000,000 per year, and total losses from applying the incorrect amount of nitrogen fertilizer exceed 110,000,000 on an annual basis (Johnson and Raun, 2003). We propose sensor-based nitrogen recommendations as a mechanism to change the farmer behavior of tradition-based fertilization practices and move towards a more sustainable system.
The sensor-based system, accurately accounts for nitrogen mineralized by biological processes and, therefore, provides nitrogen recommendations that more accurately reflect crop needs. In contrast to soil sampling and yield goals, sensor-based nitrogen recommendations allow the producer to accurately gauge the amount of N that has been mineralized through natural biological processes. This is accomplished by comparing sensor readings from normal field practices to a small area that has been supplied with a non-limiting amount of nitrogen. Wheat producers then enter values into a nitrogen-rate calculation algorithm at http://www.soiltesting.okstate.edu/SBNRC/SBNRC.php and a top-dress N recommendation is generated. So, while the research conducted to develop sensor-based recommendations is lengthy and complicated, the knowledge needed to implement use of the system is very simple and straightforward. In addition, the sensors used to obtain NDVI readings are relatively low-cost (approx. $3,500) and we feel the low-cost, high-impact nature of this technology has a high likelihood of generating entrepreneurial opportunities for limited-resource farmers wishing to generate a second line of income through consulting and advisement.
Rational and significance
When developing the idea for this project, we wanted to conduct research that would be a win: win proposition for the farmer and for the environment. Furthermore, we felt it was critical that stakeholders view the research as being relevant to their farming operations, as this would likely increase the adoption rate of technologies and practices developed from research findings. When our idea for researching no-till production systems for the southern Great Plains were presented to farmer groups, the responses indicated that it satisfied both of these criteria.
No-till management practices have great potential to increase the profitability of cropping systems in southern Great Plains while simultaneously helping to increase the biodiversity in the landscape as a whole. Agricultural benefits of no-till include greater plant-available water (Reeves, 1997), better water infiltration (Sow et al. 1998), decreased soil bulk density (Dao 1993), increased root growth, reduced infestations of aphid pests and their subsequent economic impact, and increased abundance, diversity, and effectiveness of aphid predators and parasitoids as compared to conventional tillage systems. Agronomic benefits can be further enhanced by using crop rotations to increase utilization of available water (Casal, et al., 1995; Peterson 1994). In addition, tangential benefits such as reduced soil erosion, reduced contamination of waterways with pesticides and sediment, and better wildlife habitat (Warburton 1984) have great benefit to the entire agroecosystems and extend to the surrounding landscape. We feel that lower adoption of no-till production practices by southern Great Plains farmers is a significant hurdle to long-term sustainability of agriculture in the US and a problem worthy of attention.
In summary, other SARE projects have focused on reduced and no-tillage production systems, but they have not focused on using these technologies in the unique, integrated, dual-purpose wheat production system that dominates the southern Great Plains. Research evaluating aspects of no-till production systems for this region are worthwhile because the 5.26 million hectares (13 million acres) of wheat production in Oklahoma and Texas accounts for 21% of the total US hectarage planted to wheat (Petrone, 2004). Since only 5% of this hectarage is planted using no-till production practices (Ali, 2002), our research has the potential to move over 4.9 million hectares (12 million acres) closer to sustainability through no-till production and sensor-based nitrogen recommendations. Further, the southern Great Plains are home to 5.5 million cattle annually, and since many of these cattle originate from the Pacific Northwest, Appalachia, the Southeast, and Delta states, greater sustainability in the southern Great Plains would have direct impact on the sustainability of cattle operations in many other areas of the U.S.
Cooperators
Research
Objective 1. Determine the impact of switching from conventional to no-till production practices on fall forage production and yield of winter wheat in grain only and dual-purpose wheat production system.
Oklahoma
Experimental design was a split plot arrangement of a randomized complete block with four replications. Main plots will be tillage (tillage or no-tillage), and sub-plots will be wheat variety (18-20 currently grown hard-red winter wheat varieties and approximately 5 experimental lines). Wheat sowing will occur in mid-September using a Great Plains No-Till drill with cone-seeding attachment of each year and plot size will be 1.5 m wide by 12 m long. Two identical sets of experimental plots (i.e. two identical copies of 4 replications of approximately 25 varieties) will be planted each year. One will be fenced and one will be grazed in accordance with farmer practice for each respective year of the experiment. Forage samples will be collected in late-winter from the fenced plots by hand-clipping to the soil surface, drying forage material, and weighing. Grain yield and yield component data (head counts, seed mass, harvest index, etc.) will be collected the following spring from the grazed plots. This design comes as a result of farmer requests to have both an accurate measure wheat forage production and wheat grain yield after actual grazing (as opposed to simulated grazing by mowing). Harvest operations will be performed using a small-plot combine.
Texas
Reduced and no-till systems were compared to conventional tillage systems at multiple locations in Texas’ wheat producing regions. In order to determine the core advantages or disadvantages of each tillage system, plant stand counts (seedling emergence), plant height and vigor, maturity dates, and yield were measured. In addition, soil moisture levels will be measured to determine the volumetric water content at multiple timings during the season for each tillage type. Soil compaction will also be measured at multiple times each season using a soil penetrometer. This study will be conducted for minimum of 3 years.
2. Monitor the incidence and severity of wheat diseases as well as the presence and abundance of insect pests and their natural enemies in conventional and no-till, dual-purpose wheat production systems.
Diseases. We will monitor the incidence and severity of wheat seedling and foliar diseases in the experimental plots from Objective 1. Dr. Robert Hunger (Extension Plant Pathologist, Oklahoma State University) will assist in this effort. If enough disease pressure is present, we will record disease susceptibility ratings as needed.
Insects. Our primary goals are to (1) compare aphid numbers and their estimated impact (based on Kindler et al. 2002, Giles et al. In preparation) on forage and grain yields between no-till and conventional plots, (2) compare natural enemy numbers and their estimated impact on aphid populations (based on Giles et al 2003) between no-till and conventional plots, and (3) compare the diversity of natural enemies between no-till and conventional plots. Because previous research has demonstrated similar yield loss relationships between aphid numbers and all studied greenbug susceptible wheat cultivars (Kindler et al. 2002), we will be able to group evaluations of insects on selected cultivars by main plots (no-till versus conventional). We will focus our comparisons between main plots by selecting 5 commonly grown dual-purpose cultivars and monitoring pest and natural enemies throughout each growing season in respective subplots. In Oklahoma, we will also compare data between grazed and non-grazed plots to estimate the effects of grazing (Ismail et al. 2003). In Texas, we will also sample insects and estimate yield losses in subplots where the greenbug resistant cultivar TAM 110 will be grown; a separate yield loss model has been demonstrated for this cultivar (Kindler et al. 2002, Elliott et al. 2004).
Using well established sampling procedures (Elliott et al. 1994, Michels et al. 1997, Giles et al. 2003, Royer et al. 2005 a, b, c), insect sampling will focus primarily on documenting the seasonal abundance of key aphid pest species and their primary natural enemies. Other pests and generalist natural enemies will be noted during sampling.
Sampling during wheat growth will be every 1-4 weeks as weather permits (or more frequently during high numbers) and involve (1) direct visual enumeration of all aphids and natural enemies in experimental subplots, and (2) seasonal trapping of cryptic ground dwelling predators via pit-fall traps in no-till versus conventional tillage main plots.
For each replication, in subplots of selected wheat cultivars, an arbitrarily selected 1m-row sample will be visually searched for predators and aphid species. The number of tillers will also be counted in order to quantitatively estimate densities. Data counts for predators and aphid species abundance will be recorded immediately in the field (See Royer et al. 2005 c). In addition, according to new presence-absence sampling guidelines (Giles et al. 2003, Royer et al. 2005 a, b) between 15 and 90 tillers will be inspected in order to classify both aphid population levels and parasitism percentages. Classifying the number of aphids per tiller and the minimum percentage parasitism are estimated by the proportion of tillers with one or more aphids and / or mummified/parasitized aphids (Giles et al. 2000 a, b, Giles et al. 2003, Royer et al. 2005 a, b). Using available aphid-wheat models (Elliott et al. 2004, Giles et al. In preparation), forage and grain yield losses will be estimated by the peak number of aphids / tiller present in each subplot. Actual yields as measured by clipping and small plot combine will be compared to estimated yield losses.
For each replication, in the center of subplots of selected wheat cultivars, a conical pitfall trap (filled with environmentally safe antifreeze) will be placed in the ground to monitor more cryptic ground dwelling predators. Based on current research in Oklahoma, separate fall and spring sampling 4-week periods are expected to reveal differences in species diversity between no-till and conventional tillage plots. These sampling periods will occur prior to grazing and following grazing termination, and comparisons will be made between grazed and non-grazed plots. Insects will be collected weekly, and traps will be recharged; all adult insects and spiders will be identified to species.
3. Determine if sensor-based nitrogen recommendations developed for conventional tillage systems are valid in no-tillage, dual-purpose wheat production systems.
Experimental design will be a randomized complete block with four replications. Treatments will include fall-applied nitrogen at rates of 0, 40, 80, 120, and 200 kg ha-1, normal farmer practice, and top-dress nitrogen applied according to sensor-based nitrogen recommendations. Wheat grain production and yield components (head counts, seed mass, harvest index, etc.) from the fall nitrogen treatments will be used in regression analysis to determine the optimal fall nitrogen rate; wheat grain yield from the top-dress nitrogen treatments (farmer practice and sensor-based) will be compared to the optimal rate established by regression analysis of the fall treatments.
Wheat sowing will occur in mid-September of each year using a small plot drill at some locations and farmer-owned equipment at others. Plot size will be 1.5 m wide by 12 m long. Variety choice will be determined based upon variety yield trials from harvest year 2006. Plots will be grazed according to farmer practice in the surrounding field. Harvest operations will be performed using a small-plot combine.
4. Determine the economics of no-till versus conventional tillage for dual-purpose wheat under both conventional fall nitrogen application with rates based upon yield goals and field-specific spring nitrogen application with rates based upon yield potential as measured in late winter by optical reflectance technology.
An economic engineering approach will be used to determine costs and returns for each system. The number and type of field operations (tillage, seeding, herbicide application, insecticide application, fertilizer application, and harvest) and application levels for all inputs (seed, fertilizer, herbicide, insecticide) for both conventional tillage and no-till production and both conventional and field-specific nitrogen application will be determined. A machinery complement selection program will be used to determine machine sizes and estimate machinery cost for each system for a small, midsized, and large farm. Enterprise budgets will be prepared for each system and farm size to determine the net returns to land and management and enable comparisons across systems.
5. Educate southern Great Plains wheat producers on how no-tillage production practices can enhance grain-only and wheat/stocker-cattle integrated production systems.
The primary audiences for the information that will be gathered by this project are farmers and extension educators. We plan to reach this audience using a three pronged approach. The first prong is peer-reviewed research reports and publications and scientific presentations. At the conclusion of this project, we will submit articles to refereed journals in the hope that information we gather might inspire others to conduct similar research. In addition we will generate peer-reviewed extension publications, such as fact sheets, for distribution among extension personnel and for web-based distribution. Finally, we will present findings at the American Society of Agronomy international meeting at least one year of the experiment. We will evaluate the success of these efforts by the number of publications generated.
Second we will use our research plots for training purposes for county extension educators. Specifically, we will hold at least one in-service training on best management practices for no-till wheat production each of the three years of the experiment using a hands-on, field-school approach. The idea being that once educators are properly trained they will then extend information to farmers through county meeting and field days, creating a ripple effect that will multiply the number of stakeholders influenced by our research. We will use this opportunity to educate extension professionals on how biological nitrogen cycles work and how they can be used to the producer’s advantage, glance and go sampling and other integrated pest management strategies, and disease hosts and cycles and how previous crop management can affect these in a no-till environment. We will evaluate this aspect of our project by extension educator feed back and attendance level at the in-service training.
Finally, through our use of on-farm research trials we will encourage farmer to farmer educational activities. While impact of these type activities is difficult to measure, we have found repeatedly that farmer coffee shop conversation and looking across the fence at the neighbor are two major avenues by which farmers learn new information and make decisions regarding production practices. To assist in this type of educational outlet, we have chosen prominent, innovative farmers for our cooperators. These individuals are well-spoken and well-respected in the community and can enhance the ripple effect of our research/demonstration activities. As mentioned earlier, these type activities are extremely valuable, but very difficult to measure. For this reason we will rely on feedback from farmer-cooperators for evaluation of this outreach activity.
One of the major agronomic objectives of this project is to determine if variety affects the feasibility of implementing no-till production practices. Our data indicate that variety was not significant in predicting whether or not a no-till wheat production system was successful. Variety was a major factor, however, in determining grain yield within a tillage system and in determining the impact of grazing on grain yield within a tillage system. Tillage system did not affect wheat foliar disease incidence or severity.
At the time of this report, we have collected grain yield from two harvest years at El Reno, OK. These data have revealed an average grain yield increase of 8 bu/ac associated with no-till production systems as compared to conventional-till systems in non-grazed treatments and a 6 bu/ac grain-yield increase in grazed plots. Our data have indicated, however, that fall-forage production by wheat in no-till plots was an average of 750 lb/ac less than that produced in conventional-till plots. Soil temperature and moisture data are still being analyzed, but we hypothesize that this decrease in forage production was due to cooler soil temperatures during the fall and winter months. When stakeholders were presented with these findings, they indicated that the greater load bearing strength of soil in no-till systems would result in less mud during the winter months and less energy spent by cattle moving through the mud. They indicated that they felt this would frequently offset any reductions in forage production. As one stakeholder indicated this really changes my thought process. I think my future focus should be on growing pounds of beef rather than pounds of forage.
During two years of this project, we attempted to no-till canola as a rotational crop for winter wheat. The first year of our experiment, canola produced 1,800 lb/ac of grain yield. The second year, however, our canola crop did not survive the winter. This was likely due to insufficient moisture at planting, late emergence and poor root growth. Our results indicate that further work is needed to determine the best management practices for no-till winter canola in the Southern Great Plains.
Research at our Texas locations produced similar findings as those from our Oklahoma locations. At Abilene and Prosper, TX research locations no-till wheat plots produced equal or greater grain yield than conventional-till wheat plots. Fewer aphids were observed in no-till wheat than in conventional-till wheat. Finally, research plots in Texas revealed that by using sensor-based nitrogen recommendations, growers could more accurately assess crop nitrogen requirements without detrimentally affecting crop grain yield. In 2008, for example, standard farmer practice at the research site was to apply 80 lb/ac of nitrogen to wheat pre-plant. By using in-season, sensor-based nitrogen recommendations, nitrogen rates were cut by two-thirds without negatively impacting crop yield or test weight.
Our primary goals related to insect pest management were to (1) compare insect numbers and their estimated impact on forage and grain yields between no-till and conventional plots, (2) compare natural enemy numbers and their estimated impact on aphid populations between no-till and conventional plots, and (3) compare the diversity of natural enemies between no-till and conventional plots. Wheat pest numbers (aphids and Hessian fly) and common natural enemies (ladybeetles and parasites) were counted during sampling. Collections of other natural enemies for diversity evaluations required pitfall trapping, sorting, and cataloging; these data continue to be processed. As described in our protocol, we have sampled Oklahoma and Texas locations for aphids and also for Hessian flies throughout the study.
Aphid numbers have been low (non-economic) region-wide throughout the study, but when aphids were present in Oklahoma, populations were higher in the Conventional Tillage plots. The average number of colonizing aphids during fall sampling periods were >6 times higher in the conventional plots (Table 1). These lower aphid numbers in no-till plots were expected based on previous research (Burton et al 1986).
We anticipated that aphids in the conventional plots would increase quickly, however, high levels of parasitism by Lysephlebus testaceipes during relatively mild winters essentially eliminated populations in conventional and no-till plots prior to spring wheat growth. High levels of parasitism are quite common in Oklahoma and L. testaceipes often eliminates aphids in winter wheat during the late-fall and early spring (Giles et al. 2003). Data from Spring 2009 is currently being summarized. In Texas plots, aphid numbers were significantly higher especially during the spring, however, no differences were observed between conventional and no-till plots.
Table 1. Average aphids per sample (2006-2008)
Oklahoma Locations
Fall data
Treatment Aphids
No-Till 0.9
Conventional 6.2
Spring Data
No-Till 0
Conventional 0
Texas Locations
Fall Data
No-Till 9.8
Conventional 7.9
Spring Data
No-Till 162.3
Conventional 135.9
Hessian fly numbers between conventional and no-till plots were compared in Oklahoma. Throughout the project, populations were extremely low, and as expected, fewer flies were found in the resistant cultivar ‘Duster’ (Table 2). We are continuing to sample locations for spring (2009) populations of Hessian Fly.
Table 2. Average Hessian Fly Pupae and larvae numbers per sample (2006-2008)in Oklahoma
1st Generation
Susceptible wheat Resistant wheat
No-Till 0.009 0
Conventional 0.012 0
2nd Generation
No-Till 1.5 0.2
Conventional 1.8 0
Overall, it appears that no-till wheat producers are at no greater risk of having insect pest issues than conventional tillage producers. In fact, our evidence suggests (as observed by others) that no-till systems are less attractive to common aphid pests of winter wheat. Hessian fly numbers were very low during the study, however, our data revealed that the resistant cultivar ‘Duster’ can be an effective management tool in no-till wheat systems where flies are a problem.
Educational & Outreach Activities
Participation Summary:
Extension activities for this project have focused on deliverables and grower to grower education opportunities. Individually, the PI’s of this project have conducted numerous county and area-level grower meetings on no-till methodologies. These activities have reached well over 1,500 stakeholders. In particular, our field days at the El Reno plots have been attended by over 100 stakeholders each of the three years of this project.
Similar events have been held at the TX locations. For example, a wheat tillage meeting in Young County, TX was held in 2007 with over 100 people in attendance. A Taylor/Shackleford/Callahan County Wheat Field Day was held at the Abilene, TX site with over 75 people in attendance. Information on sensor-based nitrogen recommendations was conveyed to stakeholders at ten educational events across major wheat production regions in Texas.
Through a cooperative effort among Oklahoma Cooperative Extension, NRCS, the Oklahoma Association of Conservation Districts, and various farmer participants a statewide no-till conference was organized and held in Oklahoma City in 2008 and 2009. Our group anticipated attendance of 100 stakeholders at the two-day event the first year, but over 250 stakeholders registered and attended. The second year of the event over 300 stakeholders attended. This is a testament to the thirst for knowledge about no-till farming practices among stakeholders.
List of publications
Edwards, J., F. Epplin, B. Hunger, C. Medlin, T. Royer, R. Taylor, and H. Zhang. 2006. No-till wheat production in Oklahoma. OSU Extension Facts, No. 2132. Oklahoma State Univ., Coop. Ext. Service, Stillwater, OK.
No-Till Cropping Systems for Oklahoma, E-996. Oklahoma Cooperative Extension Service. Division of Agricultural Sciences and Natural Resources. Oklahoma State University.
Epplin, Francis M. Economics Related to No-till Decisions. Component of the Conservation Tillage 101 program, Enid, Oklahoma, February 15, 2008. http://countyext.okstate.edu/garfield/CT101.htm
Decker, JonAnn E., Francis M. Epplin, Deena L. Morley, and Thomas F. Peeper. Alternative Cropping Systems for Traditional Monoculture Wheat Acres in the Southern Plains for Two Farm Sizes. Selected paper presented at the Southern Agricultural Economics Association meetings, Dallas, Texas, February 2-6, 2008.
Edwards, J., R. Kochenower, R. Austin, M. Inda, B. Carver, R. Hunger, and P. R-Duarte. 2007. Oklahoma small grains variety performance tests. PT 2007-6. Oklahoma State Univ., Coop. Ext. Service, Stillwater, OK.
Edwards, J., R. Austin, M. Inda, B. Carver, and B. Tipton. 2007. Fall forage production by winter wheat varieties in Oklahoma. PT 2007-2. Oklahoma State Univ., Coop. Ext. Service, Stillwater, OK.
Djido, Abdoulaye Ibrahim, Jeffrey D. Vitale, and Francis M. Epplin. Conventional Tillage versus No-till: Characteristics of Producers and Farms. Selected paper presented at the Southern Agricultural Economics Association meetings, Atlanta, Georgia, January 31-February 3, 2009.
Djido, A.I., J.D. Vitale, and F.M. Epplin. 2009. Conventional Tillage versus No-till: Characteristics of Producers and Farms. Journal of Agricultural and Applied Economics 41-2.
Edwards, J., and B. Hunger. 2008. Considerations when rotating wheat behind corn. OSU Fact Sheet PSS-2136. Oklahoma State Univ., Coop. Ext. Service, Stillwater, OK.
Arnall, D., J. Edwards, and C. Godsey. 2008. Reference strip series: applying your nitrogen-rich and RAMP calibration strips. OSU Current Report No 2255. Oklahoma State Univ., Coop. Ext. Service, Stillwater, OK.
Edwards, J., R. Kochenower, R. Austin, B. Carver, R. Hunger and J. Ladd. 2008. Oklahoma small grains variety performance tests. PT 2008-2. Oklahoma State Univ., Coop. Ext. Service, Stillwater, OK.
Edwards, J., R. Austin, B. Carver, and B. Tipton. 2008. Fall forage production by winter wheat varieties in Oklahoma. PT 2008-1. Oklahoma State Univ., Coop. Ext. Service, Stillwater, OK.
Project Outcomes
Respondents to a survey (n=61) distributed at the 2008 El Reno wheat field day represented a total of 67,427 wheat acres. These respondents indicated a $32.57 per acre average value of information obtained through the SARE project field day for a total of $2,196,097 in perceived value by stakeholders. In addition, only 13% of stakeholders indicated that they were no-tilling in 2005 while 40% indicate that they currently no-till in their operation. Naturally there are some external factors involved, but all indicated that data obtained from this project has assisted them in transitioning towards no-till.
Farmer Adoption
Respondents to a survey (n=61) distributed at the 2008 El Reno wheat field day represented a total of 67,427 wheat acres. These respondents indicated a $32.57 per acre average value of information obtained through the SARE project field day for a total of $2,196,097 in perceived value by stakeholders. In addition, only 13% of stakeholders indicated that they were no-tilling in 2005 while 40% indicate that they currently no-till in their operation. Naturally there are some external factors involved, but all indicated that data obtained from this project has assisted them in transitioning towards no-till.
To determine future direction of no-till efforts in Oklahoma we conducted an extensive stakeholder survey via the Oklahoma Agricultural Statistics Service. The survey indicated several trends. On average, the NT farmers crop more than twice as many acres as the CT farmers (598 versus 1,220 acres of annual crops). Fifty percent of the NT farms plant more than 1,000 acres to annual crops compared to 16 percent of the CT farms. The NT farms have more diversified cropping operations. The CT farms plant more than 90 percent of their annual crop acres to wheat. The NT farms plant only 67 percent of their crop acres to wheat.
--The NT farms rent more land for production of annual crops than the CT farms (751 versus 297 acres). Fifty-five percent of the NT farms rent more than 500 acres compared to 25 percent of the CT farms that rent more than 500 acres. Forty percent of the CT farms do not rent any land for production of annual crops.
--The use of wheat acres planted differs across the farms. For example, 73 percent of the wheat acres on CT farms are planted for dual-purpose (fall-winter forage plus grain), while only 54 percent of the wheat acres on the NT farms are planted for dual-purpose. The proportion planted for grain-only is 21 percent for the CT farms and 37 percent for the NT farms. The remaining six percent (nine percent) is planted for forage-only on the CT (NT) farms.
--The NT farms report that they use crop rotations on 69 percent of their acres. The CT group reported using crop rotations on 29 percent of their acres. Evidently these rotations on CT farms include several years of wheat since the CT group reported that 92.5 percent of their acres are seeded to wheat.
--On average the CT farmers are older. Forty-two percent of the CT group are over 65, compared to 28 percent of the NT group. Members of the CT group are more likely to work off the farm. Thirty-one percent of the CT group report that they work more than 20 hours per week off the farm compared to 18 percent of the NT group. This finding is consistent with the findings regarding acres farmed and gross sales. Since the NT group on average farms more acres and has more gross sales from farming activities than the CT group, it is consistent that they would be less likely to work off farm.
--Forty-eight percent of the NT group reported that they have been using NT for four years or less. The vast majority (96 percent) of the CT group reported that they have been using CT for more than four years.
--Reponses to questions regarding perceived benefits and perceived problems associated with NT were consistent with expectations. Farmers in the NT group are more likely to agree with statements that shed a favorable light on NT and farmers in the CT group are more likely to agree with statements that shed a favorable light on CT. The lowest average perception score among the CT group was assigned to the “increase yield” question.
Areas needing additional study
Our research and extension work indicate the potential for no-till production practices in integrated cropping systems in the Southern Great Plains. Further research is needed to determine the effects of these systems on soil physical properties such as water infiltration and soil temperature. Further research is also needed to determine if the system could benefit from the implementation of cover crops that increase residue and/or contribute nitrogen.