Effects Of Different Fertilization Methods On Nutrient Supply And Uptake Of Soil-plant System In Paddy Field

Based on long-term fertilization experiment,the experiment was conducted for clarifying the effects of long-term different fertilization on the dynamic change of nitrogen and phosphorus in paddy soil-plant system.This study analyzed the content of soil nutrients and accumulation and distribution of plant nutrients before and after rice transplanting and main growth stages in 2015.The main results were as follows:1 In this experiment,soil pH and EC did not significantly change under long-term fertilization.Compared to no fertilization,long-term application of organic manure significantly increased the content of organic matter,total nitrogen,total phosphorus,available phosphorus and potassium in soil.But it had no significant effects on nitrate and ammonium nitrogen.The effects on soil organic matter,total nitrogen,total phosphorus,available phosphorus and potassium under chemical fertilizer combined with organic manure were less than the single application of organic manure.The chemical fertilizer only had significant effects on nitrate nitrogen content in soil.Under chemical fertilizer combined with organic manure treatment and organic fertilizer treatment,the contents of soil organic matter,total nitrogen,total phosphorus and available phosphorus decreased at first and increased subsequently from heading stage to maturity stage,while the trends of these indicators were stable under no fertilization and chemical fertilizer treatment.Soil organic matter,total nitrogen,total phosphorus and available phosphorus had significant relationships.The content of available phosphorus in soil with organic manure was higher,and the risk of phosphorus loss was increased.2 Under the treatments of chemical fertilizer combined organic manure,chemical fertilizer and organic manure rice yield had significant differences to no fertilization,increasing by 62.5%,67.8%and 30.2%,respectively.According to the results,fertilizer application mainly increased the number of effective panicles.Chemical fertilizer treatment and chemical fertilizer combined with organic manure treatment had no significant differences in dry matter and nitrogen accumulation in the whole growth period.The accumulations of phosphorus of the two treatments were consistent at maturity stage,but the processes were different.Phosphorus accumulation of chemical fertilizer combined organic manure was higher than the other from tillering stage to maturity stage.Phosphorus accumulation of chemical fertilizer combined with organic manure reached a peak at filling stage,while chemical fertilizer treatment reached during the grain filling period.The content of dry matter,nitrogen and phosphorus accumulation of organic manure was higher than no fertilization,but they were significantly lower than the chemical fertilizer and chemical fertilizer combined with organic manure.The Logistic fitting of dry matter,nitrogen and phosphorus accumulation dynamics were well,and the determination coefficients were above 0.93.The day of maximum growth rate of dry matter,nitrogen and phosphorus accumulation were advanced under chemical fertilizer and chemical fertilizer combined with organic manure.3 The SPAD value and nitrogen content of the functional leaves with the treatments of chemical fertilizer combined with organic manure and chemical fertilizer were significantly higher than the treatments of organic manure and no fertilizer at spiking stage.The activities of nitrogen metabolism enzymes at heading stage were higher than that at booting stage,and there were significant differences between four treatments at heading stage.At heading stage,NR activity under chemical fertilizer treatment was the highest.GS activity was the highest under no fertilization treatment.GOGAT activity was higher under the treatment of chemical fertilizer and chemical fertilizer combined with organic manure and GDH was higher under the treatment of no fertilization and chemical fertilizer.There were significant positive correlations between GOGAT and nitrogen-related indexes at heading stage.