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

1999 Annual Report for LS99-102

Project Type: Research and Education
Funds awarded in 1999: $210,188.00
Projected End Date: 12/31/2003
Region: Southern
State: Oklahoma
Principal Investigator:
B. Dean McCraw
Dept. of Horticulture

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


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.

Much of the Oklahoma flood prone plot area held standing water for about 10 days in the spring and again in fall of 2000. Nut yields in Oklahoma plots for 1999 ranged from 692 lbs/A in un-grazed flood prone plots to 867 lbs/A in grazed flood prone plots. Non-flood, non-grazed plots averaged 1001 lbs/A while grazed non-flood plots averaged 1320 lbs/A. The Arkansas plots averaged 372 lbs/A from non grazed plots while the grazed plots averaged 534 lbs/acre.

Forage crude protein content in Oklahoma during March, 2000, averaged 20.9% in flood prone legume plots and 16.9% in flood prone non-legume plots. Protein content in the non-flood plots averaged 19.5% in legume plots and 20.5% in native plots. Forage in native vegetation plots in the non-flood area was much more lush than in flood prone areas reflecting the greater productivity of that site. Forage crude protein at the Arkansas location in March averaged 19.8% in legume plots and 17.0% in native plots.

October, 1999, soil samples indicated average surface nitrogen of 35 lbs/acre in flood plots and 23.5 lbs/a in non-flood plots in Oklahoma and 45 lbs/acre in Arkansas.

Steers in Oklahoma from April 10 through July 10 produced 40 lbs/acre more gain from legumes on flood site than from legumes on non flood site (236 vs 196 lbs/A) . Conversely, native vegetation on the non flood site produced 60 lbs/acre more gain than native vegetation on the flood site. Beef production from legumes on the flood site was similar to that from native vegetation on non-flood site. Heifers in Arkansas produced 25 lbs more gain per acre on legumes than on native vegetation.

Disease management focused on demonstration of best management practices for control of pecan scab. Scab was effectively controlled and maintained at a level below non treated orchards in OK with 3 fungicide applications made according to the Oklahoma pecan scab model. Arkansas plots required only 2 fungicide applications, the minimum recommended for native pecans.

Insect management was accomplished by scouting the plots for incidence of pecan weevil, pecan nut casebearer and pecan aphid as well as the beneficial ladybird beetles and lacewings. Pecan weevil populations were 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. 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.

Similar data will be collected from the demonstration orchards during 2001 and 2002 at which time an economic analysis will be conducted to quantify the economic benefits of the system. This project will enable farmers to manage their resources more efficiently and remain competitive in the market place while minimizing environmental impact.


Sharon von Broembsen
Extension Plant Pathologist
Department of Entomology and Plant Pathology
112F Noble Research Center
Oklahoma State University
Stillwater, OK 74078
Office Phone: 4057449960
Phillip Mulder
Extension Entolologist
Department of Entomology and Plant Pathology
127K Noble Research Center
Oklahoma State University
Stilwater, OK 74078
Office Phone: 4057449413