1. Predicting Winter Wheat Grain Yield under Grazed and Non-Grazed Production Systems
Jason Lawles

2. Objectives
To evaluate the effects of grazing winter wheat on our ability to predict yield.

3. Importance of Winter Wheat Grazing in Oklahoma
Oklahoma farms are diversified
Cow-calf, and wheat production
2003 crop year 6.4 million acres of wheat planted
2002 crop year 6 million acres planted
that 60% was grazed, 0ver 3.6million acres
2002 crop year 3.5 million acres harvested

4. Materials and Methods Experimental Sites: Experimental Design:
Hydro, Marshall Grazing Research Station
Experimental Design:
Split-block with 4 replications
2174, Ok101 wheat variety
Pre-plant N rates of 0,56,112, 168 kg ha-1 applied as
Pre-plant P flat rate of 58 kg ha-1 applied as at Hydro sites

5. Materials and Methods Experimental Design (cont.):
Forage + Grain production system
Grain-only production system

6. Initial soil test data from grazing sites
Location NH4-N NO3-N P K pH
Hydro Home place
Hydro Barn
Marshall Grazing
Research Station

7. Field Activities
Location Planting date Field size Stocking rate Days grazed lbs removed Ave. daily gain
Hydro 9/28/ acres 210lb/ac days lb/ac lb/day
Barn
Hydro 9/23/ acres lb/ac days lb/ac lb/day
Home place
Marshall 9/3/03 25 acres

12. Conclusion Harvest data will be collected
It will take three weeks to identify variability
Grazing should not effect our ability to predict yield mid-season