| In recent years,the production input of breeding process and the nutrients emissions to the water system are excessive,farmland systems nutrient cycling chain scission in the Yangtze River Delta region.To solve these problems,using field randomized block test combined with laboratory analysis,this paper sets different levels of water-borne organic and studies the effects of water-borne organic fertilizer application on rice and wheat growth and yield formation,plant nutrient absorption and nitrogen utilization,soil fertility and nitrogen loss.The nitrogen balance in rice and wheat field system with water-borne organic fertilizer was analyzed.The aim of the paper is to provide reasonable foundation of rational fertilization,controlling nitrogen loss and protecting water environment.The main conclusions are follows:1.Effects of water-borne organic fertilizer on rice and wheat growth and yield formationThe water-borne organic fertilizer significantly increases crop height and chlorophyll content,promoting accumulation of dry matter,and the yield effect is obvious.When the water-borne organic fertilizer nitrogen application rate is less than the M4(rice season nitrogen fertilizer 675 kg·hm-2,the wheat nitrogen fertilizer 562.5 kg·hm-2),the crop plant height,SPAD value,aboveground dry matter accumulation and yield were increased with the increased level of organic fertilizer.When the application rate of organic fertilizer was higher than M4,it was not conducive to the growth of crops,resulting in the decrease of yield.Chemical fertilizer can quickly provide essential nutrients for crop and promote the growth of crops at the same application rate of nitrogen fertilizer.The crop plant height,SPAD value,aboveground dry matter accumulation and yield of chemical fertilizer treatment were higher than those of the water-borne organic fertilizer treatment,but later 1000 grain weight was significantly lower than that of the water-borne organic fertilizer due to insufficient nutrient supply.2.Effects of rice and wheat nutrient use of water-borne organic fertilizerWater-borne organic fertilizer has a significant influence on plant nitrogen,phosphorus and potassium content of rice and wheat at different growth stages.With the amount of organic fertilizer increased,plant nitrogen content and potassium content increased at mature stage.However,the high amount of water-borne organic fertilizer application will reduce the phosphorus content of the plant.The water-borne organic fertilizer can increase plant nitrogen,phosphorus and potassium accumulation significantly,when the organic fertilizer application rate is higher than the M4,accumulation of plant nitrogen,phosphorus and potassium decreased.With the increased level of water-borne organic fertilizer,crop nitrogen grain production efficiency,nitrogen dry matter production efficiency and nitrogen partial factor productivity decreased.Under the same nitrogen rate,when compared with water-borne organic fertilizer,urea fertilizer can improve plant nitrogen content and accumulation of nitrogen significantly.The crop nitrogen agronomic efficiency,nitrogen recovery efficiency and nitrogen partial factor productivity of chemical fertilizer treatment is significantly higher than water-borne organic fertilizer.The crop nitrogen grain production efficiency,nitrogen dry matter production efficiency and nitrogen physiological efficiency of water-borne organic fertilizer was significantly higher than chemical fertilizer.This shows that the nitrogen proportion of organic fertilizer treatment is higher than chemical fertilizer treatment,water-borne organic fertilizer can promote the nitrogen of plant absorption transfer to the ear.3.Effects of water-organic fertilizer on soil nutrients in rice-wheat systemWater-borne organic fertilizer has a significant effect on soil nutrient content.Soil organic matter,total nitrogen,available nitrogen,available phosphorus and available potassium content were increased with the increased level of water-borne organic fertilizer.Continuous administration of water-organic fertilizer on soil organic matter and total nitrogen accumulation effect is remarkable.Compared with chemical fertilizer,water-borne organic fertilizer treatment can increase the soil organic matter and total nitrogen content significantly under the same nitrogen rate.The available nitrogen content of chemical fertilizer treatment is higher than organic fertilizer treatment at the early stage of the crop growth under the same conditions of nitrogen.Chemical fertilizer can meet crop nutrient demand timely,while the late fertilizer processing drops rapidly available nitrogen content,lower than that of organic fertilizer processing.While in the late growth stage,available nitrogen of chemical fertilizer treatment decreased rapidly and below the organic fertilizer treatment.4.Nitrogen balance analysis of farmland system under water-borne organic fertilizerThe total nitrogen,ammonium and nitrate nitrogen contentration in rice paddies of water-borne organic fertilizer treatment increased with increasing amounts of organic fertilizer.Water-organic fertilizer has a significant influence on the total nitrogen and ammonium nitrogen contentration of paddy leakage water,but little effect on nitrate nitrogen contentration.Water-organic fertilizer nitrogen rate of 810 kg·hm-2 make nitrogen contentration increased significantly in paddy field surface water and leakage water,increasing the risk of nitrogen loss.It is the peak of the concentration of nitrogen in paddy fields that 1 to 4 days after fertilization,within a week after fertilization is the critical period to control nitrogen run off loss.Under the same nitrogen rate,when compared with chemical fertilizer,water-organic fertilizer can significantly reduce nitrogen concentrations of surface water and leakage water.With the increasing of the water-borne organic fertilizer,the amount of residual soil nitrogen rapid rise,nitrogen loss and loss rates increased significantly,increasing nitrogen loss.Therefore,application amount of water-borne organic fertilizer should be controlled in the some range,it both can obtain certain economic output and has good ecological benefits.Under the same conditions of nitrogen fertilizer,nitrogen residues and losses of chemical fertilizer treatment were significantly lower than organic fertilizer treatment.So the organic and inorganic distribution is an effentive way to improve the structure of soil and reduce the loss of nitrigen. |
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