9Byers M,Bohon J.Effect of nitrogen and sulfur fertilizers on the yield,N and S content,and amino acid composition of the grain of spring wheat.J.Sci.Food Agric.,1979,30:251 ~ 263
10Dijkshaon W,yon Wijk A L.The sulfur requirements of plants as evidenced by the sulfur-nitrogen reaction in organic matter.Plant and Soil,1967,26:129 ~ 157