Effects of different tillage patterns during summer fallow on soil water conservation and crop water use efficiency

In order to seek the effects of different tillage patterns during summer fallow on soil water conservation and crop water use efficiency, a field study was conducted to determine the effect of conservation tillage on soil water and winter wheat yield in arid areas of southern Ningxia from 2007 to 2010. Tillage treatments comprised NT/ST/NT (no-tillage in first year, subsoiling tillage in second year, again no-tillage in third year), ST/NT/ST (subsoiling tillage in first year, no-tillage in second year, again subsoiling tillage in third year), CT (conventional tillage in 3 years). The results showed that conservation tillage patterns could improve soil water condition in wheat field and significantly increase crop yield and water use efficiency. At the end of summer follow period, compared with CT, the 3-year mean soil water storage of NT/ST/NT and ST/NT/ST treatments in the 0-200 cm soil layers increased by 3.92% and 7.84% (P<0.05), the 3-year mean fallow rainfall storage efficiency increased by 13.64% and 22.80% (P<0.05), respectively. During wheat growing season, the 3-year mean soil water storage (0-200 cm) in NT/ST/NT and ST/NT/ST increased by 7.96% and 8.60% (P<0.05), mean growing season rainfall use efficiency increased by9.59% and 10.69% (P<0.05), mean year rainfall use efficiency increased by9.52% and 10.65% (P<0.05), respectively. Compared to CT, the 3-year mean wheat yield for NT/ST/NT and ST/NT/ST increased by 9.59% and 10.69% (P<0.05), mean grain yield water use efficiency increased by 7.17% and 7.68% (P<0.05), mean biomass yield water use efficiency increased by 3.83% and 4.34% (P<0.05), respectively.