Grain yields were improved by conservation tillage with straw cover or straw standing,and that of NPS20,NPS40,NS40,NS20,NSB40 and NSB20 were increased by 53.08%,46.59%,40.81%,19.93%,17.33% and 4.34% respectively compared with the CT.

• 结果表明；留茬覆盖免耕保护性耕作提高了春小麦的产量；NPS20；NPS40；NS40；NS20；NSB40和NSB20较CT分别增产53.；08%25；46