摘要
【目的】N_2O是重要的温室气体之一,主要来源于农田土壤。华北平原是我国的粮食主产区,秸秆还田是该地区主要的农田管理措施,明确不同秸秆还田量对小麦玉米农田周年土壤温度和含水量的影响以及与N_2O排放之间的量化关系,对发挥秸秆还田的生态效应,明确硝化和反硝化作用机制具有重要意义。【方法】以冬小麦、夏玉米为研究对象,设置5种不同秸秆还田量处理:小麦、玉米秸秆均不还田(T0);小麦秸秆1875 kg/hm^2+玉米秸秆2000 kg/hm^2还田(T1);小麦秸秆3750 kg/hm^2+玉米秸秆4000 kg/hm^2还田(T2);小麦秸秆5625kg/hm^2+玉米秸秆6000 kg/hm^2还田(T3);小麦秸秆7500 kg/hm^2+玉米秸秆8000 kg/hm^2还田(T4)。于2014年10月~2015年10月,采用静态箱–气相色谱法对农田N_2O排放进行测定,探究不同秸秆还田量下小麦玉米农田N_2O排放的周年变化,并量化分析土壤温度、含水量与N_2O排放的关系。【结果】秸秆还田量显著影响N_2O的排放,随着秸秆还田量的增加,周年内N_2O排放总量呈增加的趋势,增加量为1.33~3.50 kg/hm^2,增加率为32.3%~85.0%;通量增加量为15.52~40.87μg/(m^2·h),增加率为32.3%~85.1%。玉米季N_2O排放通量和总量分别是小麦季的2.42~2.62和1.05~1.14倍。秸秆还田可提高0—10 cm土壤温度和0—20 cm土壤含水量,增加范围分别为0.63~2.14℃和0.6%~1.8%。相关性分析表明,各处理土壤温度和N_2O排放通量无相关关系(P>0.05)。T0、T1、T2处理土壤含水量与N_2O排放通量呈显著正相关(P<0.05),而T3、T4处理与N_2O排放通量之间不相关(P>0.05)。【结论】随着秸秆还田量的增加,N_2O排放通量和总量均呈现增加趋势,且玉米季高于小麦季。秸秆还田显著促进N_2O排放并可提高0—20 cm土壤含水量和0—10 cm土壤温度,周年秸秆还田量在7750 kg/hm^2及以下时,N_2O排放通量与土壤含水量之间呈显著正相关,而与土壤温度之间不相关。
Abstract： [ Objectives ] Nitrous oxide （N2O） is one of the important greenhouse gases that mainly come from farmland soils. Straw returning is an effective ecological management in North China. Quantitative analysis of the N2O emission and the affecting factors is of great significance for deep understanding of nitrification and denitrification mechanism in the wheat-maize system. [ Methods ] A field experiment with five different amounts of straw incorporation was carried out in the winter wheat and summer maize, including without straw returning （TO）, returning 1875 kg/hm： wheat straw and 2000 kg/hm2 maize straw （T1）, returning 3750 kg/hm2 wheat straw and 4000 kg/hm2 maize straw （T2）, returning 5625 kg/hm2 wheat straw and 6000 kg/hm2 maize straw （T3）, and returning 7500 kg/hm2 wheat straw and 8000 kg/hm2 maize straw （T4）. From October 2014 to October 2015, the N2O flux was determined using static chamber technology combined with gas chromatography, the annual variation of N2O flux and their relationships with soil temperature and moisture were analyzed. [ Results ] The straw returning amounts affected the N2O flux significantly, which was increased with the increase of straw retuming amounts. The seasonal N2O emission was increased by 1.33-3.50 kg/hm2 in amount, or 32.3%-85.1% in rates. The average N2O flux were increased by 15.52-40.87 ~tg/（m2.h） in amount, or 32.3%-85.1% in rates. The average N2O flux and total emission during the maize season were respectively 2.42-2.62 times and 1.05-1.14 times of those in the wheat season. The straw returning increased the temperature in 0-10 cm layer of soil by 0.63-2.14~C and moisture in 0-20 cm layer of soil by 0.6%-1.8%, respectively. The correlation analysis showed that the N2O flux had no correlation with soil temperature, had an exponential correlation with soil moisture in treatment TO, T1 and T2 （P 〈 0.05）, but not with those in treatment T3 or T4. [ Conclusions ] With the increase of straw returning amounts, the average N2O flux and seasonal emission will be increased, which are higher in the maize season than in the wheat season. The straw retuming could increase soil temperature in 0-10 cm layer and soil moisture in 0-20 cm layer significantly. The N2O flux has an exponential correlation with soil moisture when the annual straw returning amounts are less than 7500 kg/hm2, while had no correlation with soil temperature.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2017年第3期589-596,共8页
Journal of Plant Nutrition and Fertilizers
基金
国家自然科学基金(31101083
31471414)资助
关键词
秸秆还田
氧化亚氮
土壤含水量
土壤温度
straw returning
nitrous oxide
soil moisture
soil temperature
