Effects of Combined Application of Organic Manure and Chemical Fertilizers on Ammonia Volatilization from Greenhouse Vegetable Soil

【Objective】Excessive use of chemical nitrogen fertilizers suffer from nitrogen loss through ammonia(NH3) volatilization,resulting in decreasing effectiveness of the fertilizers and increasing the risk of environmental pollution.Less information is available on the effect of different fertilization patterns on NH3 volatilization from greenhouse vegetable soils.Based on balanced fertilization and optimized irrigation,this study was conducted to determine the effect of combined application of organic manure and chemical fertilizers on NH3 volatilization.【Method】A field experiment was designed to study the dynamics of NH3 volatilization by the venting method under celery-tomato rotation system in Tianjin from September 2010 to June 2011.The field experiment consisted of six treatments of 1(No N),2(4/4 CN+0/4 PN,all nitrogen in chemical fertilizer,PN denotes nitrogen in pig manure),3(3/4 CN+1/4 PN),4(2/4 CN+2/4 PN),5(2/4 CN+2/4 SN,SN denotes nitrogen in straw),and 6(CF,conventional fertilization).Equal NPK was designed for treatments 2,3,4,and 5.Rates of P2O5 and K2O application were respectively equal for each of treatments 1,2,3,4 and 5.【Result】 The peak of NH3 volatilization rate occurred within 2-3 days after basal fertilization,whereas in first day after fertilizer top-dressing(fertilization and irrigation were carried out simultaneously) during the celery and tomato growth period.The NH3 volatilization rate from the nitrogen application treatment closed to the rate from the no nitrogen application treatment until first 8-10 days after basal fertilization and first 10-11 days after fertilizer top-dressing,respectively.70%-80% of total NH3 volatilization during celery or tomato growth period were from over the first 10 days after basal fertilization to the first 11 days after the second fertilizer top-dressing.Distinct total NH3 volatilization during tomato growth period with higher temperature was found,with the total amounts of NH3 volatilization for all treatments being 3.0 times as high as that of the celery growth period.Compared with the conventional fertilization with much higher rates of N fertilizer,the combined application patterns of organic manure and chemical fertilizers significantly decreased the total NH3 volatilization by 50.0% and 49.6% during the celery and tomato growth period,respectively.The NH3 volatilization gradually decreased with the increase of the organic nitrogen rates.Straw application compared with pig manure application with the same N rate respectively decreased the NH3 volatilization by 32.4% and 30.0% during the growth period of celery and tomato under this experimental condition.The proper pattern of combined application of organic manure and chemical fertilizers based on yield,income and environment was the pattern of combined application of 3/4 N in chemical fertilizer and 1/4 N in organic manure under this experimental condition.【Conclusion】The pattern of combined application of organic manure and chemical fertilizers significantly decreased the total NH3 volatilization,with the fertilization pattern being economic benefit-significantly,feasibility-strongly and environment-friendly,and its application in sustainable greenhouse vegetable production is prospective.