Effects of Different Tillage Practices on Soil Physical Properties and Crop Yield in the Region of Southern Ningxia

In order to solve the problems of insufficient precipitation, shallow plough layer and low water use efficiency in the dry land of Southern Ningxia, we investigated the effects of different tillage practices on soil physical properties and crop yield in the region of southern Ningxia, and provided certain theory support for improving the topsoil structure reasonably in dryland, selecting the suitable tillage practice and increasing crop yield and benefit.

using potato and spring wheat as test crops, two tillage methods and four tillage depths of conventional ploughing 20 cm (C20, as a control), deep ploughing 30 cm (C30), subsoiling 30 cm (S30), subsoiling 40 cm (S40) and subsoiling 50 cm (S50) were set in arid region of southern Ningxia between 2019 and 2020 for the two-year field experiment to study the effects of different tillage methods with depths on soil bulk density during the harvest period, soil compactness water storage, and crop biomass during the growth periods,, yield and water use efficiency.

The average soil bulk density at 0-60 cm layer in potato season and spring wheat season under the S50 treatment was significantly decreased by 6.49% and 6.94%, compared with the control treatment. In the whole growth period, the average soil compactness with the S50 treatment in potato season and spring wheat season was the lowest, which was significantly increased by 19.32% and 8.11%, respectively, compared with the control treatment. The improvement in the soil water storage with the S50 treatment during the whole growth period in potato season and spring wheat season was the best, which was significantly increased by 13.58% and 25.66%, respectively, compared with the control treatment. The S40 treatment had the highest dry matter accumulation in potato season and spring wheat season. Crop yield, net income and water use efficiency were the highest under the S40 treatment in potato season and spring wheat season, which were significantly increased by 15.20%, 18.90% and 9.10% in potato season, and increased by 59.24%, 88.20% and 28.98% in spring wheat season, when compared with the control treatment. The tillage methods with depths had extremely significant effects on soil water storage, crop biomass and yield, while soil density and compactness were extremely affected by tillage methods.

The tillage method combined with depth could significantly improve the topsoil structure, and increase soil water storage during the crop growing period, thereby promoting the increase of crop yield and water use efficiency. The subsoiling 40 cm treatment had the best effect of crop yield and income increasing in potato and spring wheat season, and it could be further promoted and applied in the cultivation of potato and spring wheat for high yield and efficiency in the region of southern Ningxia.