Abstract: With micro­plot experiment,this paper studied the effects of applying organic materials on the dynamics of nitrogen and phosphorus,and their availability in paddy soil.The results showed that during rice growth period,the nitrogen (ammonia­N and nitrate­N) and phosphorus contents in soil solution were decreased with time,and significantly correlated with the dosage of chemical fertilizers and the DOC content in soil solution.Organic materials application could not only increase rice biomass,but also increase the use efficiency of nitrogen and phosphorus fertilizers.¹⁵N tracer indicated that compared with applying chemical fertilizers,organic materials application could significantly increase the availability and maintenance of soil nitrogen,which in turn decreased soil nitrogen loss.

Key words: Citrus, High temperature stress, Photosynthesis, PSⅡ