Effects Of Resin Coating Residue Of Controlled-Release Fertilizers On Soil Physical And Chemical Properties And Growth Of Crops

Controlled release fertilizers coated with resin not only has high utilization efficiency of fertilizer, but aslo has the characteristics of less nutrient leaching and volatilization. The nutrient release rate of controlled release fertilizer was accordant with plant nutrient absorption, and controlled release fertilizers can provide the plant the needed amount of nutrients timely. With the development and application of controlled-release fertilizers, there would be a lot of polymer coating residual left in the soil after a long-term using, A pool-simulation field rotation experiment and soil column leaching were designed in this study. The purpose of this paper was: 1) to study the effects of CRFs residual coating on the growth of winter wheat and summer corn and grain quality; 2) to illustrate the effects of CRFs residual coating on soil property; 3) to define the degradation products of CRFs residual coating in the soil after short term. The main results were summarized as follows:1. Effects of CRFs coating residual on soil physical and chemical property:In the field cultivation conditions, the soil bulk density, proportion, total porosity, field capacity, pH and EC of silt and sandy soil could not be reflected significantly when the coating residual was ranged from 90 to 360 g/m~2 in the soil.The soil column leaching experiment showed that the water permeability of silt loam decline and the field capacity increase when the content of CRFs residual coating was less than 720g/m~2.With the content of redual coating increasing,the water permeability of silt loam was strengthened, the bulk density of silt loam was reduced and porosity increased.The field capacity and bulk density of loamy sand did not change significantly, but the permeability of loanmy sand increased when the content of polymer coating residual was less than 2880g/m2.2. Effects of CRFs coating residual on the growth of winter wheat and summer corn: the amount of polymer coating residual was simulated about 40 years of application of release fertilizers, the results showed that the plant heigh, chlorophyll,dry weight, root volume, maximum leaf area of winter wheat and summer corn were not changed significantly by polymer coating residual, but the root activity of maturing winter wheat has reduced in the loamy sand.3. Effects of CRFs coating residual on the yield and quality of the winter wheat and summer corn: the crude protein, crude ash, Vc content, yield and the content of the major mineral elements, such as N, P, K in the grain of winter wheat and summer corn were not affected by the application of CRF resin coating within the range of 90~360 g/m2. However, when the applied dosage was 90, 180 and 360 g/m2, the starch contents of summer corn in loamy sand soil were increased by 23.83%, 41.73% and 23.17% compared to the no coating residual treatment, respectively.4. Effects of CRFs coating residual on the leaching of soil nutrients: the results showed that the amount of nitrogen leached increased in the silt loam with the increasing of polymer coating residual, but the content of nitrogen leached did not change obviously. Besides the amount of N and P leached in the silt loam did not change significantly. However the amount of N and P leached in the loamy sand increased gradually with the increasing of polymer coating residual.5. The extraction of degradation products of CRFs resin coating in the soil: the results showed that the main degradation products were low molecular weight alkanes.