Alternative Dryland Cropping Systems to Wheat Fallow.

Winter wheat-summer fallow  (W-F) in the Central Great Plains of the U.S.A. is not a long term sustainable dryland system. Utilizing no-till and more intensive cropping we have developed several alternative rotations to wheat fallow. In this paper, we examine rotation benefits that though inconsistent from year to year are greater in the longer four year rotations than in three year rotations. Twenty three different 2 year, 3 year, and four year rotations were developed using the dryland crops, wheat, corn , proso-millet, sunflower, forage triticale, pea and forage millet. Summer fallow was also included in several of the rotations. Market yield, biomass, water use and nutrient use were measured over a 12 year period (3 complete cycles of the four year rotations). We found that in 5 of the last 8 years of the 12 year period that wheat yields after fallow were 9-28 % greater in the four year rotations than in WF. With three year rotations a similar trend was observed.  However the yield increases were less.  When averaged over the whole12 year period yield differences due to rotation were insignificant.