Effects Of Applying Vermicompost Organic Fertilizer On Paddy Soil Nutrients And Absorption

A large number of fertilizers in the past years led to a decline of soil quality in Northeast Black Surface,which has became the development restriction factor of modern agriculture in Northeast China.As the most important commercial grain storage depot,Heilongjiang Province is also facing the problem of declined soil quality.The organic fertilizer has good effect on soil character improvement,which can improve the soil fertility of rice field so as to reduce the chemical fertilizer pollution.On the basis of previous work,this study aimed to treduce fertilizers used in the cultivation of rice in Northeast,and pot experiment was conducted to investigate the effect of vermicompost organic fertilizers combined with chemical fertilizer on soil physicochemical property and enzyme activity of paddy fieldsas wellas nutrient utilization and photosynthetic characteristics of rice in Northeast China,providing theoretical support for the rational application of organic fertilizer in the paddy field,which is o f great significance to protect the healthy development of farmland ecosystems.This study conducted a two-year pot experiment,setting a total of 8 vermicompost organic fertilizer application levels（CK,CK0,T1,T2,T3,T4,T5,T6）.The experiment data of 2 years of potted rice was carried out.The following conclusions was drawn by statistical analysis,:（1）The contents of total nitrogen,alkaline hydrolysis nitrogen,available phosphorus and available potassium of paddy soil under each fertilization treatment increased to varying degrees,Compared with the unfertilized treatment（CK）and the conventional fertilizer treatment（CK0）,it is significantly improved.The results showed that chemical fertilizer reduction by 30%+vermicompost treatment（T3）had the best effect on the whole,which increased（total nitrogen）by53%,（alkaline hydrolysis nitrogen）by 25.8%,（available phosphorus）by 30.4%and（available potassium）by 12.9%compared with CK.（2）Vermicompost organic fertilizer combined with chemical fertilizer could significantly improve soil enzyme activity,fertilization treatments increased soil dehydrogenase,phosphatase,invertase,urease and catalase activities.Compared with the CK0 treatment,the chemical fertilizer reduction by 30%+vermicompost treatment（T3）increased significantly by 87.2%,54.4%,50.3%,24.5%,and 6.2%.（3）The total nitrogen,total phosphorus and total potassium of rice stem and root were significantly increased by all treatments,the chemical fertilizer reduction by 30%+vermicompost treatment（T3）achieves the best results.Compared with the conventional fertilizer treatment（CK0）（CK0）,it increases（nitrogen content in rice stem）20.0%,（phosphorus content in rice stem）23.6%,and（potassium content in rice stem）16.5%,（nitrogen content in rice root）82.6%,（phosphorus content in rice root）16.5%,（potassium content in rice root）18.1%,which showed that they could be controlled by the amount of fertilizer applied,and the nutrient content of rice plants could be increased by the combination of vermicompost organic fertilizer combined with chemical fertilizer.（4）The results showed that there were significant differences in net photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO₂ concentration among the treatments.Compared with the unfertilized treatment（CK）and the conventional fertilizer treatment（CK0）,vermicompost organic fertilizer combined with chemical fertilizer increased the net photosynthetic rate of rice more effectively,and T3 treatment had the best effect.The yield and yield relate d indexes of each treatment（T1～T6）were improved,and the nitrogen utilization rate of each treatment（T1～T6）was higher than CK and CK0,the highest value was reached by chemical fertilizer reduction by 30%+vermicompost treatment（T3）.（5）Correlation analysis of soil nutrients and soil enzyme activities showed that alkali-hydrolyzable nitrogen has positively correlated with total phosphorus,a vailable phosphorus,dehydrogenase and phosphatase.There was a positive correlation between total phosphorus and available phosphorus,phosphatase and dehydrogenase.Rice plant nutrients were correlated with photosynthetic indexes and showed the same dyna mic changing trend,there was a significant correlation between net photosynthesis rate,transpiration rate,stomatal conductance and intercellular CO₂ concentration.