Demonstration of a Sustainable Integrated Production System for Native Pecan and Beef Cattle Producers and its Effect on Ecology in Flood Prone Areas

Demonstration of a Sustainable Integrated Production System for Native Pecan and Beef Cattle Producers and its Effect on Ecology in Flood Prone Areas

Summary

In a native pecan and beef production system in naturally flooded or un-flooded sites in Oklahoma and Arkansas the highest pecan yield was from non flooding plots regardless of grazing or forage treatment. Legume plots had the highest nut yield whether grazed or flooded. In the OK trial beef gain was highest on non-flood plots with native vegetation. In flood prone plots beef gain was highest on legume forage. In AR beef gain was highest on legume plots. Grazing reduced tree leaf N content whether flooded or not. Legumes met tree N requirements whether grazed or not.

Objectives/Performance Targets

• Demonstrate the effects of a legume based grazed native pecan orchard management system on soil N fixation, soil characteristics and beneficial insect attraction.

  Accomplished
  Objective 1 is complete. Soil samples have been collected from both sites twice each year and analyzed for nutrient content. Grazing reduced tree leaf N content whether flooded or not. The reduction ranged from 6.3% in flooded legume plots to 3.1% in flooded native vegetation plots. Trees in legume plots maintained minimum recommended leaf N levels without supplementary fertilization whether grazed or flooded. Supplemental N fertilization in amounts ranging up to 150 lbs N per acre, was required on native plots to maintain tree leaf N content above minimum level of 2.4%.
  Pecan aphid populations were slightly greater and beneficial organisms were slightly lower in native forage areas than in legume plots. Pecan nut casebearer adult populations were similar in flooded or un-flooded areas of the orchard but greater in grazed than un-grazed plots. Adult casebearer populations were greater in legume plots than native vegetation plots. Pecan nut casebearer damage was similar across all treatments.

  Remaining tasks
  All requirements complete.

  Accomplished
  Objective 2 is complete. Insect management was accomplished by twice weekly scouting the plots for incidence of pecan weevil, pecan nut casebearer and pecan aphid as well as the beneficial lady beetles and lacewings. The scouting form was completed in triplicate and one copy left with the grower at each visit. Pesticide application was accomplished only as dictated by threshold calculation. During 2000 pecan weevil populations tended to be greater in the non-flood areas than in the flood plane. Weevil numbers recovered were also greater in grazed than in un-grazed sites. Pecan aphid populations were greater in flood areas than in un-flooded sites and higher in grazed than un-grazed plots. Pecan aphid populations were slightly greater and beneficial organisms were slightly lower in native forage areas than in legume plots.
  Disease management continues to focus on demonstration of best management practices for control of pecan scab. Scab was effectively controlled and maintained at an economic level in OK with minimum fungicide applications made according to the Oklahoma pecan scab model. Arkansas plots used the phenology scab spray model.

  Remaining to do
  All requirements complete.

  Accomplished
  Objective 3 is complete. Comparison benefits from the AR demonstration were reduced due to expression of what appears to be “barnyard effect”, essentially a severe zinc deficiency, in the grazed, native vegetation plot and to tree damage in all plots from an ice storm in December 2000.
  Natural flooding in the Oklahoma flood prone plot was consistent with the intent of the project. Harvest data have been collected for four years at both sites. Grazing data have been collected for three years at both sites.
  Average pecan yield over 4 years ranged from 483 lbs. per acre in non flood native vegetatin plots to 698 pounds per acre in non flood grazed plots. Non flood legume plots, regardless of grazing or forage treatment. Legume plots produced higher nut yield than native vegetation plots whether grazed or flooded. Nut yield from non-grazed plots in the AR test varied. In grazed plots, trees with legumes out yielded those with native vegetation. Nut yield in the Arkansas plots were too variable for conclusion due to ice storm damage and nutritional disorder.
  In the OK trial average beef gain was highest (307 lbs/A) on non-flood plots with native vegetation. In flood prone plots beef gain was highest (226 lbs/A) on legume forage (Table 2). Data from the July thru August grazing period revealed little or no gain probably due to excessive heat and associated effects on the cattle. The summer grazing period can serve essentially as a holding area for the cattle to take advantage of the microclimate among trees as it likely does no harm to the trees. Cattle must be removed by Sept 1 in preparation for pecan harvest.
  Remaining to do
  Requirement complete

  Quantify treatment effects on changes to the plant community.
  Unable to complete this objective due to relocation of the ecologist assigned to the project.

  Quantify the economic benefits of legumes, weevil trapping, scab monitoring and grazing in a native pecan system.

  Accomplishments
  Mr. Jason Lopez, PhD student under the direction of Dr. Joe Schatzer in the Department of Agricultural Economics is currently in possession of all data from this project and is incorporating it into his dissertation project. That will be complete at the end of the fall, 2003 semester.

1. 1.Demonstrate the effects of a legume based grazed native pecan orchard management system on soil N fixation, soil characteristics and beneficial insect attraction.

   2.Demonstrate trapping and weather monitoring to schedule pecan weevil and scab spray programs compatible with livestock.

   3.Demonstrate a fully integrated and sustainable legume based beef and native pecan production system.

   4.Quantify treatment effects on changes to the plant community.

   5.Quantify the economic benefits of legumes, weevil trapping, scab monitoring and grazing in a native pecan system.

Accomplishments/Milestones

Objective 1 is complete. Soil samples have been collected from both sites twice each year and analyzed for nutrient content. Grazing reduced tree leaf N content whether flooded or not. The reduction ranged from 6.3% in flooded legume plots to 3.1% in flooded native vegetation plots. Trees in legume plots maintained minimum recommended leaf N levels without supplementary fertilization whether grazed or flooded. Supplemental N fertilization in amounts ranging up to 150 lbs N per acre, was required on native plots to maintain tree leaf N content above minimum level of 2.4%.
Pecan aphid populations were slightly greater and beneficial organisms were slightly lower in native forage areas than in legume plots. Pecan nut casebearer adult populations were similar in flooded or un-flooded areas of the orchard but greater in grazed than un-grazed plots. Adult casebearer populations were greater in legume plots than native vegetation plots. Pecan nut casebearer damage was similar across all treatments.

Remaining tasks
All requirements complete.

Accomplished
Objective 2 is complete. Insect management was accomplished by twice weekly scouting the plots for incidence of pecan weevil, pecan nut casebearer and pecan aphid as well as the beneficial lady beetles and lacewings. The scouting form was completed in triplicate and one copy left with the grower at each visit. Pesticide application was accomplished only as dictated by threshold calculation. During 2000 pecan weevil populations tended to be greater in the non-flood areas than in the flood plane. Weevil numbers recovered were also greater in grazed than in un-grazed sites. Pecan aphid populations were greater in flood areas than in un-flooded sites and higher in grazed than un-grazed plots. Pecan aphid populations were slightly greater and beneficial organisms were slightly lower in native forage areas than in legume plots.
Disease management continues to focus on demonstration of best management practices for control of pecan scab. Scab was effectively controlled and maintained at an economic level in OK with minimum fungicide applications made according to the Oklahoma pecan scab model. Arkansas plots used the phenology scab spray model.

Remaining to do
All requirements complete.

Accomplished
Objective 3 is complete. Comparison benefits from the AR demonstration were reduced due to expression of what appears to be “barnyard effect”, essentially a severe zinc deficiency, in the grazed, native vegetation plot and to tree damage in all plots from an ice storm in December 2000.
Natural flooding in the Oklahoma flood prone plot was consistent with the intent of the project. Harvest data have been collected for four years at both sites. Grazing data have been collected for three years at both sites.
Average pecan yield over 4 years ranged from 483 lbs. per acre in non flood native vegetatin plots to 698 pounds per acre in non flood grazed plots. Non flood legume plots, regardless of grazing or forage treatment. Legume plots produced higher nut yield than native vegetation plots whether grazed or flooded. Nut yield from non-grazed plots in the AR test varied. In grazed plots, trees with legumes out yielded those with native vegetation. Nut yield in the Arkansas plots were too variable for conclusion due to ice storm damage and nutritional disorder.
In the OK trial average beef gain was highest (307 lbs/A) on non-flood plots with native vegetation. In flood prone plots beef gain was highest (226 lbs/A) on legume forage (Table 2). Data from the July thru August grazing period revealed little or no gain probably due to excessive heat and associated effects on the cattle. The summer grazing period can serve essentially as a holding area for the cattle to take advantage of the microclimate among trees as it likely does no harm to the trees. Cattle must be removed by Sept 1 in preparation for pecan harvest.
Remaining to do
Requirement complete

Quantify treatment effects on changes to the plant community.
Unable to complete this objective due to relocation of the ecologist assigned to the project.

Quantify the economic benefits of legumes, weevil trapping, scab monitoring and grazing in a native pecan system.

Accomplishments
Mr. Jason Lopez, PhD student under the direction of Dr. Joe Schatzer in the Department of Agricultural Economics is currently in possession of all data from this project and is incorporating it into his dissertation project. That will be complete at the end of the fall, 2003 semester.

Impacts and Contributions/Outcomes

This project is highly successful. The Oklahoma demonstration served as an excellent field day site with over 300 persons in attendance in June 2000. A field day at the Arkansas in April 2002 attracted 20 people. Results of the project were presented at the Langston University Small Farm and Alternative Agriculture Symposium on the Langston University campus during August 2001. Over 150 growers of various crops were in attendance. A summary of the results was presented at the Kerr Center for Sustainable Agriculture’s “Future Farms 2002″ conference in Oklahoma City with over 200 in attendance.
The pecan industry survey to identify the program’s effect is currently under analysis by a commercial survey company. Over 2400 surveys were mailed with nearly 700 returns. Results will be complete in late summer 2003.

Collaborators: