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DRYLAND CROPPING SYSTEMS

Conversion of Conservation Reserve Program (CRP) Grassland for Dryland Crops in a Semiarid Region

^a USDA-ARS, Conservation and Production Res. Lab., P.O. Drawer 10, Bushland, TX 79012 USA

pwunger{at}ag.gov

Information was needed regarding practices suitable for returning grassland to cropland when Conservation Reserve Program (CRP) contracts expired. A study on Pullman soil (Torrertic Paleustoll) involved seven tillage treatments (no-tillage and reduced, sweep, disk, moldboard plus disk, burn–sweep, and burn–disk tillage) with vegetation retained and the five non-burn tillage treatments with vegetation removed before treatment. Fertilizer (NH₄NO₃) was applied at 0, 34, and 67 kg N ha^-1 in 1995 and at 0, 67, and 134 kg N ha^-1 in 1996 and 1997. Initial soil water contents were low, and soil never was filled with water at planting time. Sorghum [Sorghum bicolor (L.) Moench] yielded 720 kg ha^-1 in 1995, and the 1995–1996 wheat (Triticum aestivum L.) crop failed. Sorghum was not planted in 1996 because of a drought. Sorghum yielded 2260 to 4700 kg ha^-1 in 1997. Wheat yielded 1410 to 1980 kg ha^-1 in 1996–1997. Vegetation retention or removal affected yields slightly. Fertilization affected sorghum yields slightly and increased wheat yields. Vegetation control was difficult with no-tillage. Disk tillage to dislodge grass, followed by reduced- or no-tillage, appears best for converting CRP grassland to cropland in this semiarid region. Because of low initial soil water contents, a 90-d period is inadequate for obtaining adequate soil water storage unless precipitation is much above normal. Forgoing planting a crop soon after killing the vegetation when precipitation is low would provide more time for storing soil water and increase the potential for obtaining favorable yields.

Abbreviations: CRP, Conservation Reserve Program

This article has been cited by other articles:

				P. W. Unger Erosion Potential of a Torrertic Paleustoll after Converting Conservation Reserve Program Grassland to Cropland Soil Sci. Soc. Am. J., November 1, 1999; 63(6): 1795 - 1801. [Abstract] [Full Text] [PDF]