9Jordan D, Hubbard V C, Stecker J A. Earthworm response to rotation and tillage in a Missouri clay pan soil[J]. Biology and Fertility of Soils,1999,29(4):343-347.
10Doyle A D. Kingdon R W. Effect of sowing rote on grain yield, kernel weight, and grain portent percentage of barly in northern new south wales[J].Aust J Exp Agric, 1992,32:465-471.