Root Traits Spatial Distribution of Different Yield Level Summer Soybean in the South of Hebei Province

For probing into the relation between seed yield and root trait in soybean,fifteen summer soybean varieties with relative higher and lower yields in mid-south of Hebei province were used for researching on spatio-temporal root traits in field.At 18,30,45,65 days after seeding,the root morphological and physiological traits were obtained with root-drill.Results showed that during middle-later growth time,the root fresh weight,root total length and root areas of relative low yield varieties centralized in surface soil layer,but being more even in different soil layer in that with relative high yield.The root reduce activity of relative high yield varieties were higher evidently than that of relative low yield varieties.The root traits and their relative values in deep soil layer had higher relativity with yield,and especially in 10~20 cm soil layer all root traits relative values showed significant difference at the 0.01 probability level between two yield types.The spatial distribution variation of root traits in high yield verities could resist venture of soil nutrition short during their vigorous growth time and kept longer functional period of root,possibly being one of the important reasons of taking the high grain yield.