Effects of Permanent Raised Beds on Soil Chemical Properties in a Wheat-Maize Cropping System

Traditional tillage (TT) in the North China Plain has maintained grain productivity in the past 50 years. Nonetheless, it has also been a major contributor to global greenhouse gas emissions, biodiversity and soil fertility loss, soil degradation, and even desertification. Permanent raised beds (PRB) have been proposed as a viable solution to achieve sustainable farming in this plain. The effects on soil chemical properties of the PRB treatment and two other treatments, namely, no-tillage and TT treatments, were measured between 2005 and 2011 in the annual double cropping regions of the North China Plain. The soil properties significantly (P < 0.05) affected by the different treatments. Stratification ratios of soil organic carbon, total nitrogen, available N, available phosphorus, and available potassium under PRB (>1.35) were significantly (P < 0.05) higher than those under no-tillage and TT. In the cropping zone of PRB, the bulk density was significantly reduced by 14.4%, whereas soil organic carbon, total nitrogen, phosphorus, and potassium and available nitrogen, phosphorus, and potassium in the 0- to 10-cm soil layer were significantly increased by 24.8%, 78.8%, 121.9%, 81.8%, 46.2%, 7.0%, 2.9%, respectively, in comparison with those of TT treatments. Winter wheat and summer maize yields in PRB also underwent a slight increase. Permanent raised beds seem to be an improvement on current farming systems in the North China Plain and valuable for the sustainability of farming in this region.