The object of the study was to identify the suitable tillage system in lime concretion black soil,and provide basis for the improvement of the soil fertility and continuous increase of crop yield in lime concretion black soil.Five treatments,namely,rotary tillage in autumn+no-tillage in summer(ART+SNT,CK),subsoiling in autumn+no-tillage in summer(ASS+SNT),deep mouldboard ploughing in autumn+no-tillage in summer(ADMP +SNT),deep mouldboard ploughing in autumn and sublevel subsoiling in summer(ADMP+SSSS),deep mouldboard ploughing in autumn and lateral subsoiling in summer(ADMP+SSSL),were carried out to investigate the effects of time and pattern of deep tillage on the contents of soil organic matter,total nitrogen,available phosphorus,available potassium,and yield of winter wheat and summer maize.The results showed that deep tillage increased the contents of organic matter,total nitrogen,available phosphorus and available potassium in 15—40 cm soil layer,thus increased winter wheat and summer maize yields,and the effects in winter wheat growth period were bigger than those in summer maize growth period.The improvement effects of deep tillage on soil nutrient content and crop yield in autumn combined with subsoiling in summer were better than those of single deep tillage in autumn. Compared with the single deep tillage treatment in autumn,the contents of soil organic matter,total nitrogen,available phosphorus and available potassium of deep tillage in autumn combined with subsoiling in summer increased by 10.5%,6.6%,12.3% and 6.0% in 15—40 cm soil layer respectively,and winter wheat-summer maize yield increased by 3.6%.In the five treatments,ADMP+SSSL treatment had the best improvement effect on soil nutrient content,and the highest yield. The contents of soil organic matter,total nitrogen and available phosphorus and available potassium in 15—40 cm soil layer and winter wheatsummer maize yield of ADMP+SSSL treatment increased by 7.9%,9.5%,38.8%,7.9% and 2.9%,respectively,compared with ADMP+SNT treatment,and by 28.2%,30.9%,217.7%,20.4% and 17.3% respectively,compared with ART+SNT treatment. The improvement of soil nutrient content and crop yield of ADMP+SSSL treatment was the best in the five treatments,which was the suitable time and pattern of deep tillage in lime concretion black soil.