Effect of straw returning on nutrients change in soil solution during rice growth period

Rice straw returning can reduce environmental pollution and improve the fertility of soil.This research was conducted in experiment and practical base of Northeast Agricultural University with two treatments,straw returning and no straw returning to rice field and study the change of inorganic nitrogen,phosphorus and potassium content in soil solution.The results showed that the content of NH4+-N increased in the treatment of straw returning,and the concentration of NO3--N showed as two main respects: two treatments were similar in earlier stage and NO3--N was reduced by straw returning in later period.The concentration of P was decreased by application of straws at earlier stage,and the content of P increased gradually and exceeded the content of no returning with growth stage progressing.The change of K was the most obvious because of straw application.The content of K in the straw returning treatment was higher than that of no returning during the whole growth period.