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United States Department of Agriculture

Agricultural Research Service

Title: Converting Crp Land to a Wheat-Sorghum-Fallow Rotation

Authors
item Unger, Paul
item Jones, Ordie

Submitted to: Conservation Reserve Program Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 22, 1996
Publication Date: N/A

Interpretive Summary: A wheat-sorghum-fallow rotation is suitable for dryland crop production in the southern and central Great Plains, but adequate water and nutrients must be available for good plant growth and yields. This may not be the case when CRP grassland is converted to cropland. Treatments in our study near Bushland, TX, were moldboard plowing, disking, sweep plowing, and no-tillage. The grass was left on the land for some treatments, but baled or burned for other treatments. Because of low soil water storage and rainfall, sorghum yields in 1995 and wheat yields in 1996 were low. Sorghum was not planted in 1996 because of the drought. Based on our experiences, we offer the following: (1) Start conversion to cropland as soon as possible; (2) Start controlling perennial weeds before the contract ends; (3) Expect soil water contents to be low when grass is plowed out. Soil water contents may be low at planting time for the first planned crop. .Consider not planting a crop if water contents are low or planting a crop that depends less on soil water contents at critical growth stages (for example, a forage crop); (4) Expect soil nutrient contents, especially nitrogen, to be low. Apply adequate fertilizer based on a soil test. Split applications of nitrogen may be desirable; (5) Removing most of the above-ground grass makes it easier to work the land. Disking to cut out the bunches of grass and to loosen the soil followed by sweep plowing resulted in the best soil condition. The soil was rough after moldboard plowing and disking was needed to prepare a seedbed; (6) Plant water stress on no-tillage plots resulted in poor grass control with herbicides for our first crop (grain sorghum). Better control was obtained when plants were less stressed for water.

Technical Abstract: A wheat-sorghum-fallow rotation is suitable for dryland crop production in the southern and central Great Plains, but adequate soil water and nutrients must be available for good plant growth and yields. This may not be the case when CRP grassland is converted to cropland. Treatments in our study near Bushland, TX, were moldboard plowing, disking, sweep plowing, and no-tillage with grass left on the land, baled, or burned. Because of low water storage and rainfall, sorghum yields in 1995 and wheat yields in 1996 were low. Sorghum was not planted in 1996 because of the drought. Based on our experiences, we offer the following: (1) Start conversion to cropland as soon as provisions of the contract allow; (2) Start control of perennial weeds before the contract ends; (3) Expect soil water contents to be low when grass is plowed out. Because water contents may be low at planting time, consider not planting the first planned crop or planting a crop that is less dependent on soil water contents at critical growth stages; (4) Expect soil nutrient contents, especially N, to be low. Apply adequate fertilizer based on a soil test. Split applications of N may be desirable; (5) Removing most above-ground dry matter (grass) improves workability of the land. Disking to cut out the bunch grass and loosen the soil followed by sweep tillage gave the best soil condition. Moldboard plowing caused an extremely rough condition that required disking to prepare a suitable seedbed; (6) Plant water stress on no-tillage plots caused poor grass control with herbicides for our first crop (grain sorghum). Control was better when plants were less stressed for water.

Last Modified: 11/23/2014
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