不同用量生物质炭降低华南集约化菜地土壤N_(2)O排放和提高氮肥利用率的效应  

Effects of different amounts of biochar on reducing soil N_(2)O emission and increasing nitrogen use efficiency under intensive vegetable production in South China

作　　者：陈宗海 石梦玄 刘一戈 李博 卢瑛[1] CHEN Zong-hai;SHI Meng-xuan;LIU Yi-ge;LI Bo;LU Ying(College of Resources and Environment,South China Agricultural University,Guangzhou,Guangdong 510642,China)

机构地区：[1]华南农业大学资源环境学院,广东广州510642

出　　处：《植物营养与肥料学报》2024年第6期1053-1063,共11页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然科学基金项目(42277290,41807021)。

摘　　要：【目的】我国集约化蔬菜种植氮肥施用量大、复种指数高、农事操作频繁,导致土壤氮素损失量大,氮肥利用率低。生物质炭施用可有效改善土壤物理、化学和生物学性质,进而影响土壤氮素循环以及作物产量。比较不同生物质炭用量对土壤N_(2)O减排和作物产量的影响及作用机理,为生物质炭在蔬菜栽培中的应用提供指导。【方法】田间试验在华南地区进行,在连续两年内共种植4茬多次收获蔬菜。试验设置不施氮肥(CK)、常规施氮(NF)、常规施氮+20 t/hm^(2)生物质炭(NB20)和常规施氮+40 t/hm^(2)生物质炭(NB40)处理,采用静态暗箱—气相色谱法对两年蔬菜生长季的土壤N_(2)O排放量和蔬菜产量进行测定,田间试验结束后采集土样测定土壤理化性质和酶活性。【结果】生物炭施用两年后,NB20和NB40处理的土壤全氮、pH、有效磷和脲酶活性均显著高于NF,NB20处理的pH和有效磷含量又显著高于NB40处理。两年试验NF处理菜地土壤N_(2)O排放通量范围为42.8~7233.0μg/(m^(2)·h),生物质炭处理为28.4~3188.1μg/(m^(2)·h),温度、季节和氮肥施用是引起波动的主要因素。与NF处理相比,2018、2019年NB20处理的N_(2)O累积排放量分别显著降低了64.3%、66.9%,NB40处理分别显著降低了55.8%、62.5%,但两处理之间无显著差异。与NF处理相比,NB20处理的蔬菜产量显著增加了10.1%~29.10%,产量尺度N_(2)O排放显著降低了56.4%~74.4%,氮素吸收量因而显著增加了13.9%~32.9%,两年之间多数指标变化不显著;NB40处理第一年的增产、降排效果与NB20处理无显著差异,第二年的产量和氮素利用率显著低于NB20处理,也低于第一年。相关性分析和冗余分析表明,土壤pH是影响N_(2)O排放的主要因素,土壤有效磷、pH和有机碳是影响蔬菜产量的主要因素。【结论】在华南集约化蔬菜生产中,配施生物质炭能显著缓解大量氮肥施用产生的土壤酸化,增加土�【Objectives】Intensive vegetable cultivation in China is characterized by high nitrogen fertilizer application,multiple crop rotation and harvest.The frequent fertilization practice required by this production system leads to high nitrogen loss inevitably.The application of biochar has been proved of effectively improving soil physical,chemical and biological properties,and affecting the soil nitrogen cycle and crop yield.We studied the effects and mechanisms of different amounts of biochar application on N_(2)O emission and crop yield.【Methods】A field experiment was conducted for continuous two-years in South China,and Indian lettuce and asparagus lettuce were cultivated in turn each year,with multiple harvests in each vegetable during their growing seasons.The experiment was consist of four treatments,including:no nitrogen fertilization control(CK),conventional nitrogen fertilization(NF),conventional nitrogen fertilization plus 20 t/hm^(2)biochar(NB20)and 40 t/hm^(2)biochar(NB40),respectively.The static dark box-gas chromatography was used to measure soil N_(2)O emissions during the vegetable growing season.Soil samples were collected at the end harvest of the vegetables for measurement of soil physico-chemical properties and enzyme activities,and total vegetable yields were recorded.【Results】Compared with NF at the end of two-years of experiment,biochar application significantly increased soil total N,pH,available P and urease activity(P<0.05),and NB20 treatment was recorded significantly higher pH and available P than NB40.The soil N_(2)O emission fluxes ranged from 42.8 to 7233.0μg/(m^(2)·h)under NF treatment,and 28.4 to 3188.1μg/(m^(2)·h)under biochar treatments,depending on temperature,season,and nitrogen fertilization.Compared with NF treatment,NB20 significantly reduced the cumulative N_(2)O emissions by 64.3%−66.9%,and NB40 reduced that by 55.8%−62.5%,and there was no significant difference between the two treatments in the reduction effect.However,NB20 treatment significantly increas

关 键 词：生物质炭 华南地区 集约化菜地 N_(2)O 氮素利用率 

分 类 号：S154.1[农业科学—土壤学]