Effects of sowing methods on soil carbon density and composition in the alfalfa and Bromus inermis pasture

A experiment was conducted to investigate the soil organic carbon density and oxidative stability coefficient among four grasslands by multilayer sampling method, including twoyear alfalfa single pasture, Bromus innermis single pasture, interlacing mixture pasture of alfalfa and B. innermis, and inline mixture pasture of alfalfa and B. innermis. This study indicated that the soil organic carbon density was the biggest with the 11.59 t/hm2 in the interlacing mixture pasture of alfalfa and B. innermis, and was the second in the alfalfa single pasture during the growth season. The soil organic carbon density in the interlacing mixture pasture of alfalfa and B. innermis and alfalfa single pasture was significantly greater than that in the B. innermis single pasture and inline mixture pasture of alfalfa and B. innermis (P＜0.01). The highest oxidative stability coefficient was found in the interlaced mixture pasture of alfalfa and B. innermis with 1.28 and the oxidative stability coefficient was 1.16 in the inline mixture pasture of alfalfa and B. innermis. The oxidative stability coefficient of alfalfa single pasture and B. innermis single pasture were 1.00 and 0.85, respectively. This study implied that Mixed sowing was the better for the stabilization of soil organic matter and interlacing mixture method was better than inline mixture method.