Permanent Raised Beds Improved Soil Physical Properties in an Annual Double-Cropping System

Content:As a typical semi-humid area with a wheat ( Triticum aestivum L .)–maize ( Zea mays L.) annual double-cropping system, Beijing has the lowest food production per capita and is suffering from severe soil degradation and low seedbed temperature in winter. This study evaluated the permanent raised bed (PRB) system in Beijing from 2005 to 2011 to investigate the effects of combining no tillage, residue cover, and controlled traffic with raised beds for improving soil properties. We found that the overall soil bulk density (0–30 cm) in PRB plots was significantly ( P < 0.05) lower (by 12.4%) than that in traditional tillage (TT) plots, while the penetration resistance in the 10- to 20- and 20- to 30-cm soil layers of PRB plots was 18.2 and 26.1% lower ( P < 0.05), respectively, than that of TT. The percentage of water-stable soil macroaggregates (>0.25 mm) in the PRB plots was 89.8% ( P < 0.05) higher than in the TT plots, while the soil temperature was approximately 1.3 and 1.0 ° C higher under TT at the 5- and 15-cm depths, respectively, in winter. With these improvements, yields of PRBs appeared to have an increasing trend compared with no-till and TT treatments