Comparative study on runoff N, P from organic and conventional rice-wheat rotation field in the tai lake region in china

The runoff N, P from organic and conventional rice-wheat rotation field in terms of equal N input was studied through field plot test in Tai lake region. The results showed that in the rice-wheat rotation field in Tai lake region the runoff TN from organic and conventional field was 56.15kg/hm2 and 77.90kg/hm2 respectively, 27.9% less from organic field; for the runoff N coefficient, in organic field, rice season it’s 7.19% and wheat season 9.12%, in conventional field, rice season it’s 9.74% and wheat season 16.75%; the runoff TP from organic and conventional field was 2.38 kg/hm2 and 1.03 kg/hm2, respectively, 131.06 % more from organic field; for the runoff P coefficient, in organic field, rice season it’s 0.84 % and wheat season 0.14%, in conventional field, rice season it’s 1.1 % and wheat season 0.05 %. In rice field, NH4-N was the main form of runoff TN and in wheat field, NO3-N was the main form of runoff TN. Analysis suggested that more runoff P from organic field was because of more P input from organic fertilizer in case of equal N input in organic and conventional field.