A compare exerperiment on the contribution to N in potting soil from a field of grass and crop rotation among native alfalfa, wheatgrass, tall fescue, Siberian wildry, awnless brome and spring wheat was conducted in Xinjiang.

• 试验比较了紫花苜蓿、春小麦与冰草、牛尾草、老芒草和无芒雀麦等禾本科牧草对种植土壤氮素的影响。