7Bulle C W,Soper R J, Bailey L D. Phosphorus-nutrition of soybeans as affected by placement of fertilizer phosphorus [ J ]. Canadian Jour- nal of Soil Science,1983,63(2) :199-210.
8Taylor H M, Mason W K, Bennie A T P, et al. Response of soy- beans to two row spacing and two soil water levels : I. An analysis of biomass accumulation, canopy development, solar radiation inter- ception and components of seed yield [ J]. Field Crops Research, 1982,5 : 1-14.
