GREENHOUSE SURVEY STUDIES (GSS) ON UPLAND LATOSOL SOIL NUTRIENT STATUS IN GUANGDONG PROVINCE

The nutrient status of 11 upland latosol soil samples collected in Guangdong province was surveyed by Gss method originated from Dr.A.H.Hunter.The results indicated that the selected soils were quite deficient in N and P.Treatments of no N and P addition presented the decrease of sorghum seeding dry weight by about 50%.K addition showed marked effects on sorghum in the soils developped from granite.With the soils developped from other parent material,the treatmint of no K addition decreased the sorghum seedling dry weight by about 30% or less.On the soils with pH values lower than 5.0,lime was also an important limiting factor and had similar performance to N and P application on crops.As for Mg,it was generally an effective element,and able to increase the sorghum seedling dry weight by 16%~40%.S was not deficient in the selected soils,no significant effects of S addition were obtained.With regard to micronutrients,Cu should be taken into consideration.Significant effect of Cu addition was presented in 6 among 11 soil samples.No distinct effects of B,Moor Zn addition wo showed.As for Fe and Mn,the application of theirs did not show marked effects because they were sufficient in these soils.