Crop Yield Benefits of No-till in Semi-Arid Dryland Cropping Systems of the Northern and Central Great Plains.

Many published manuscripts document yield improvement with no-till practices in semi-arid regions. On the other hand, a recent review of 610 experiments from a variety of climatic conditions documented overall reduced yields with no-till. In that paper the authors also mention that under certain conditions no-till results in higher or equivalent crop yields. Our objective is to share data from several long-term field experiments from the Northern and Central Great Plains that document grain yield increases with no-till practices. Some of these experiments reported wheat (Triticum aestivum L.) yields in no-till winter wheat-summer fallow (WF-nt) systems that are on average 35% greater than wheat planted in conventionally tilled wheat-fallow (WF-ct). No-till technology and more intensive cropping (reduced frequency of fallow results in annualized grain yields that are as much as 66% greater than annualized grain yields in conventionally tilled WF. Increased soil water evaporation resulting from tillage results in significantly lower grain yield compared with no-till systems where herbicides control weeds. Our analysis indicates that the most favorable no-till rotations in the Central and Northern Great Plains are more diverse than WF. For example, in the Central Great Plains the best rotations are winter wheat-summer crop-fallow (W-SC-F), where the summer crops used include corn, (Zea Mayes L.) sorghum (Sorghum Bicolor L.), proso millet (Panicum miliacium L.) and sunflower (Helianthis annuusL), and no-till four-year rotations of W-SC-SC-F. The poorest performance was always measured with WF-ct.