No-Till Diversified Cropping Systems for Efficient Allocation of Precipitation in the Southern Great Plains

Core IdeasPrecipitation allocation increased from 45 to 85% when using diversified crop rotations.Shifting timing of fallow periods increased growing season precipitation allocation.Diversified crop rotations exhibited lower total water losses during fallow periods than continuous wheat rotations. Conventional till continuous winter wheat (Triticum aestivum L.) is a common cropping system in the portion of the Southern Great Plains (Kansas, Oklahoma, and Texas) with >600 mm annual precipitation. This cropping system contributes to soil erosion and uses resources such as precipitation, land, and time inefficiently. Therefore, new cropping strategies are needed. The objective of this research was to determine how no-till diversified cropping systems affect precipitation allocation and precipitation storage efficiency relative to conventional till continuous wheat. Five crop rotations of varied diversity were studied including the following crops: winter wheat, corn (Zea mays L.), sunflower (Helianthus annus L.), grain sorghum [Sorghum bicolor (L.) Moench.], and soybean [Glycine max (L.) Merr.]). The experimental design was a randomized complete block in two location and 2 yr. Soil water content (SWC) to a 2-m depth was measured weekly with a neutron probe. Regardless of the cropping system, nearly 80% of precipitation during fallow periods was lost. Eighty-five percent of the annual precipitation was received during the crop growing seasons in the diversified cropping systems compared with 48% in continuous wheat. Fallow periods were inefficient regardless of cropping intensification and shifting fallow periods from summer to winter months resulted in more efficient use of precipitation in the diversified cropping systems.