Increasing Sustainability of Southern Great Plains' Agriculture Through No-till Production Systems

Increasing Sustainability of Southern Great Plains' Agriculture Through No-till Production Systems

Summary

Experiments to evaluate conventional-till and no-till wheat production systems were initiated in the fall of 2006 at two locations in Oklahoma and two locations in TX. Thus far no-tillage wheat plots produced less fall wheat forage than conventional-till wheat plots but statistically equal wheat grain yield. We have recorded fewer insect pests in no-till than in conventional till. Extension efforts have included a no-till handbook and a large-scale no-till conference with over 250 attendees.

Objectives/Performance Targets

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.

Accomplishments/Milestones

OVERVIEW

A late spring freeze and record rainfall during harvest made for a challenging wheat production environment during the 2006/2007 crop. In spite of these challenges, we were successful in collecting our first year’s data and in establishing wheat plots for the 2007/2008 crop year. In addition, we were very successful in our outreach and extension activities during 2007. In the next few paragraphs we will outline some of the major accomplishments from years one and two of our Southern Region SARE project.

RESEARCH ACTIVITIES

No-till vs. conventional till variety tests were established at El Reno and Okeene, OK in the fall of 2006. The Okeene site was abandoned in 2007 due to spring freeze injury and excessive moisture during harvest season. The Okeene plots were moved to a better field location in the fall of 2007 and were planted behind grain sorghum. Stand establishment was successful and our farmer cooperator has provided additional land to ensure that the grain sorghum / wheat rotation can be continued in the latter years of the project.

One of the major agronomic objectives of this project is to determine if variety affects the feasibility of implementing no-till production practices. At the El Reno, OK location, tillage and variety impacted forage and grain yield, but the interaction of tillage and variety was nonsignificant in the 2007 harvest year. Conventional-till plots yielded an average of 1,070 lb/a more dry forage than no-tillage plots (3,330 vs. 2,260 lb/a). No-till variety plots, however, reached the critical first hollow stem stage of growth an average of four days later than conventional-till plots. Since first hollow stem is the optimal timing for removal of cattle from wheat pasture, later first hollow stem equals more grazing. 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. No-till and conventional-till plots produced statistically equivalent grain yield and test weight, and grazing by stocker cattle reduced yield by 7 bu/a in both systems as compared to non-grazed plots. Canola was grown at the El Reno site to serve as a rotational crop for wheat sown in the fall of 2007. Canola yield in both systems was 1,800 lb/a.

Research plots were initiated at the Prosper and Abilene, TX locations on 25 October and 1 November 2006. The tillage treatments at Prosper included a no-tillage, reduced tillage, and conventional tillage treatments. The tillage treatments at Abilene were no-tillage and conventional tillage. The wheat varieties planted at Prosper and Abilene were Pioneer 25R47 and Agri-Pro Cutter, respectively. These varieties were selected based on their past performance in variety trials across the state. Pre-emergence and early post-emergence herbicides were used to control troublesome weed species at each location. Plant stand counts were taken in early-winter for each tillage treatment. Within each treatment, at least 150 ft2 was harvested to estimate wheat yields. Yields were corrected for moisture and 60 lbs/bu test weight.

Tillage treatment did not affect wheat grain yield at Abilene or Prosper in 2006 or 2007. Average grain yield at Abilene and Prosper were 26 and 24 bu/a in 2006 and 52 and 67 in 2007. Test weight was not impacted by tillage at either location in 2006. The no-tillage treatment produced higher test weight (53.5 vs. 52.8 lb/bu) than the conventional tillage treatment at Prosper in 2007.

Similar methodology was used for plot establishment and data collection for the 2007/2008 crop year. The Abilene location, however, was lost when our farmer cooperator inadvertently tilled the research plot area. After discussing various alternatives with project investigators, we decided re-initiating a new research site may provide inaccurate or misleading results and will focus all future efforts on the Prosper, TX site. Wheat was planted on 2 October 2007 at Prosper. The Prosper location was expanded in the 2007-08 trial to include numerous soft and hard red winter wheat varieties in each tillage regime. These varieties were selected based on their past performance in variety trials and the regional planting of soft red winter wheat in the Prosper area. Plant stand counts were taken in early-winter for each tillage treatment. Each tillage treatment was split in half to make the plots 40’x100’. One half of the each tillage treatment received the top-dress nitrogen application based on the current Texas A&M University recommendation of 1.5lbs of nitrogen per 1 bushel of expected yield. Base on cropping history and the current crop condition, the expected yield will be 50 bu/a. The remaining one half of the tillage treatment received a top-dress nitrogen application based on the recommendation of the Greenseeker Technology which was calibrated based on a nitrogen rich strip. Currently, the wheat crop looks very good and no major problems are expected.

Under Objective 2, our primary goals are to (1) compare aphid 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 are counted in the field during sampling, whereas natural enemies are sorted, cataloged and continue to be processed. As described in our protocol, we have sampled Oklahoma and Texas plots for aphids and also for Hessian flies during the second year of our study.

Aphid numbers have been highly variable region-wide (See tables below) during year 2. When aphids were present, populations were higher in Conventional Tillage Plots, with the exception of the TX location in early February where aphid numbers were similar between tillage treatments. We are continuing to sample locations, and sort and count aphid and natural enemy samples.

Average aphids per sample among 4 cultivars at 1 Oklahoma location (11-28-07)

Location Treatment Cultivar Aphids

El Reno(OK) No-Till Jagger 0.88
Conventional Jagger 5.25

No-Till Jagalene 0.75
Conventional Jagalene 4.13

No-Till OK Bullet 0.50
Conventional OK Bullet 6.62

No-Till Duster 0.13
Conventional Duster 7.25

Average aphids per sample at 1 TX location (2-6-08)

Location Treatment Aphids

Prosper (TX) No-Till 300.5
Conventional 252.3

When Hessian flies were present (very low numbers), populations were slightly higher in Conventional Tillage Plots. As expected, no Hessian flies were found in the resistant cultivar ‘Duster’. We are continuing to sample locations for spring populations of Hessian Fly.

Average Hessian Flies per tiller among 4 cultivars at 2 Oklahoma locations (11-28-07)

Location Treatment Cultivar Aphids

El Reno(OK) No-Till Jagger 0.03
Conventional Jagger 0.03

No-Till Jagalene 0.06
Conventional Jagalene 0.07

No-Till OK Bullet 0.02
Conventional OK Bullet 0.04

No-Till Duster 0
Conventional Duster 0

Okeene (OK) No-Till Jagger 0
Conventional Jagger 0

No-Till Jagalene 0
Conventional Jagalene 0

No-Till OK Bullet 0
Conventional OK Bullet 0

No-Till Duster 0
Conventional Duster 0

All data sorting and summarization will be completed by July 2008.

EXTENSION ACTIVITIES

Extension activities for the first two years of 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 1,000 stakeholders. In particular, our 2007 field day at the El Reno plots was attended by approximately 100 stakeholders. Sixty four of these stakeholders responded to a survey distributed at the field day event. These stakeholders represented over 58,000 acres of wheat production and estimated the value of the information they received at the field day at $10.50 per acre or a total of over $600,000 in perceived value among stakeholders.

Similar events were 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. The tillage research plots served as demonstrations for the educational event. Planting, fertility, and pest management were the primary discussion points of the presentation.

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 February. Our group anticipated attendance of 100 stakeholders at the two-day event. Over 250 stakeholders registered and attended. This is a testament to the thirst for knowledge about no-till farming practices among stakeholders. Plans are to make this an annual event.

Part of our project focuses on wise use of nitrogen fertilizer through sensor-based nitrogen recommendations in no-till. As part of this project, investigators worked with county extension personnel to get these technological advancements into the hands of farmers. Fertilizer application information was recorded for 586 fields where Extension personnel had placed Ramp Calibration Strips (RCS) in the fall of 2006. Each RCS has an associated contact person who was responsible for collecting sensor data and completing an associated data sheet. Items of particular importance are the fertilizer rates and recommendation. The fertilizer rates included the amount of N applied preplant, traditional topdress rate, and actual amount of N that was applied in the spring. The traditional topdress rate was what the producer would typically apply in the absence of the sensor information. Data collected from over 100 of the 586 fields used in 2006 indicated that typical nitrogen topdress rate was 110 lbs/ac. The average recommended rate from reference strips was about half the typical rate at 53 lbs nitrogen per acre. The average nitrogen rate applied to these fields was 80 lbs/ac. While farmers did not completely accept the reference strip recommendation, it appears that they were willing to reduce nitrogen rates somewhat. They applied an average of 25% less nitrogen than typical. Assuming nitrogen costs 50 cents per pound, farmers saved an average of $15/ac. This is similar to what research has shown. Extrapolating this data to all wheat acres can easily show a 7 figure benefit to Oklahoma wheat growers. Nitrogen reference strips were applied on 269 fields in the fall of 2007. Some of these fields will have nitrogen trials to evaluate the impact of nitrogen rate decisions on crop yield.

Finally, a diverse group of researchers and extension personnel came together to publish a no-till handbook for Oklahoma and the southern Great Plains. This, along with other publications from 2007, are listed below:

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.

Edwards, J.T. 2007. Wheat extension and wheat management research. Ann. Wheat Newsletter. 53:148-149.

Edwards, J.T. (ed.), R.M. Hunger, T.A. Royer, H.A. Zhang, and C.R. Medlin. 2007. Wheat Production Newsletter. Vol. 3: Issues 6-17; Vol. 4: Issues 1 – 4.

Impacts and Contributions/Outcomes

This research will make the dual-purpose wheat production enterprise more sustainable by answering critical questions about genotype performance, nitrogen management, and insect pests and their natural enemies in no-till production systems. Information gathered will help change the opinions and practices among dual-purpose wheat farmers in the region and result in an increase in no-till production practices on the 13 million acres of wheat sown annually in the region.

Collaborators: