Effects Of Slow And Controll-Released Fertilizer Types And Fertilization Modes On Ammonia Volatilization And Greenhouse Gas Emission

In order to address the problem that ammonia volatilization emissions and greenhouse gas emissions from paddy fields caused by nitrogen fertilizer application in rice production,which do great harm to the environment and aggravate the global greenhouse effect,this experiment adopted the combination of controlled releasing nitrogen fertilizer and single basal application(SBN),and combined with the indicators,such as rice yield and yield composition,dry matter accumulation of rice and nitrogen absorption of rice,etc.,so as to explore the effects of different fertilizer types and fertilization modes on ammonia volatilization and greenhouse gas emissions and provide theoretical basis for reducing ammonia volatilization and greenhouse gas emissions from paddy fields based on the emission fluxes of ammonia volatilization and greenhouse gas from paddy fields.The experiment was carried out in the rice experimental base of Nanjing Agricultural University,Yanling Town,Danyang City,Jiangsu Province,from 2017 to 2018.Two fertilization methods(spraying and mechanical side-bar fertilization)and three controlled-releasing nitrogen sources(sulfur coated urea,SCU,resin coated urea,PCU,slow-mixing fertilizer,BBF)were set up,conventional fractional fertilization(CK1),Local traditional fertilization(CK2)and no nitrogen(NO)were used as controls to study the effects of different methods of controlled-releasing nitrogen fertilizer on ammonia volatilization and greenhouse gas emission from paddy fields with machine-transplanted rice seedlings.The main results are as follows:1.Effects of different fertilization patterns of controlled releasing nitrogen fertilizer on rice growth and yield formationCompared with CK,BBF and SCU significantly improved the recovery efficiency of nitrogen fertilizer in rice,and significantly enhanced rice yield by increasing the number of effective panicles in different treatments of side-bar fertilization;PCU significantly increased the nitrogen content of rice plants at each critical growth stage;SCU significantly increased the dry matter accumulation at each critical growth stage.By studying the growth and development of rice under different fertilization methods,it was found that compared with spraying,side-bar fertilization significantly increased leaf area index and flag leaf SPAD at panicle differentiation and heading stages of controlled-releasing nitrogen fertilizers,the plant nitrogen uptake at all stages of rice plant and the recovery efficiency of nitrogen fertilizer in rice.2.Effects of different fertilization patterns of controlled releasing nitrogen fertilizer on ammonia volatilization and greenhouse gas emission from paddy field.Compared with CK,controlled releasing nitrogen fertilizer had longer ammonia volatilization emission time and lower volatilization amount in all side-bar fertilization treatments,BBF significantly reduced ammonia volatilization emission from paddy fields,and the release rate was relatively gentle,of which the peak rate of ammonia volatilization was significantly lower than other fertilizers;SCU peaked one week after transplanting,then gradually decreased,and there was no ammonia volatilization at about one month after transplanting;PCU peaked at the latest and appeared only at the panicle differentiation stage of rice.Controlled releasing fertilizer could effectively reduce nitrogen loss through ammonia volatilization,and there were significant differences in total ammonia volatilization among different fertilizer treatments.The ammonia volatilization loss was successively ranked from low to high under each fertilizer treatment,namely BBF,PCU,CK and SCU,and the ammonia volatilization loss of BBF treatment was significantly lower than that of other controlled releasing fertilizer treatments.In addition,controlled releasing fertilizer significantly reduced N20 and CH4 emissions from paddy fields.Compared with SCU and PCU,BBF significantly reduced N20 and CH4 emissions from paddy fields.In general,N20 emissions had remained at a relatively low level,and there would be a small peak during the period of soil drying in the fields,of which the performance was consistent in 2017 and 2018.By comparing different fertilization modes,the total ammonia volatilization,CH4 and N2O emissions of side-bar fertilization treatment were significantly lower than those of spraying treatment,of which the performance was consistent in 2017 and 2018.