【作者】 汪婧；

【导师】 张仁陟；

【作者基本信息】 甘肃农业大学 ， 生态学， 2011， 硕士

【摘要】 本文通过设置在甘肃省定西市李家堡镇的不同耕作措施试验,即T:传统耕作不覆盖;NT:免耕不覆盖;TS:传统耕作结合秸秆还田;NTS:免耕秸秆覆盖。于2010年研究了春小麦-豌豆轮作模式下不同耕作措施对作物生育期内土壤呼吸速率、甲烷（CH₄）、氧化亚氮（N₂O）通量的释放规律及其影响因素,以便为寻找旱地温室气体减排技术提供科学依据。结果表明:1.旱作农田土壤呼吸速率的生育期变化春小麦地传统耕作处理、豌豆地免耕秸秆覆盖处理较其他处理相比能显著降低土壤呼吸速率。不同耕作处理下春小麦地平均土壤呼吸速率依次为NTS>TS>NT>T,NTS最高为0.2418μmol·m^-2·s^-1,T最低为0.2036μmol·m^-2·s^-1;豌豆地则为NTS<TS<NT<T,T最高为0.2736μmol·m^-2·s^-1,NTS最低为0.2181μmol·m^-2·s^-1。2.旱作农田生态系统CH₄通量的生育期变化不同耕作措施下春小麦地、豌豆地在整个生育期内均为CH₄的净吸收汇,春小麦地、豌豆地免耕不覆盖及免耕秸秆覆盖处理有利于对CH₄的吸收,尤以春小地显著。不同耕作措施下春小麦地CH₄吸收通量大小为NTS>NT>TS>T,NTS最高为0.0818 mg.m^-2.h^-1,T最低为0.0416 mg.m^-2.h^-1;豌豆地则为NT>NTS>T>TS,NT最高为0.0737 mg.m^-2.h^-1,TS最低为0.0416 mg.m^-2.h^-1。3.旱作农田生态系统N₂O通量的生育期变化不同耕作措施下春小麦地、豌豆地在整个生育期内表现为N₂O的排放源,免耕不覆盖、免耕秸秆覆盖、传统耕作结合秸秆还田处理均能明显减少春小麦地和豌豆地N₂O的排放。不同耕作措施下春小麦地平均N₂O排放通量依次T>NT>TS>NTS,T最高为0.0891 mg.m^-2.h^-1,NTS最低为0.0461 mg.m^-2.h^-1;豌豆地则为T>NT>NTS>TS,T最高为0.1234 mg.m^-2.h^-1,TS最低为0.0350 mg.m^-2.h^-1。4.旱作农田温室气体排放的影响因素春小麦地土壤呼吸速率、CH₄吸收通量与土壤温度、土壤含水量分别成显著正相关关系,N₂O排放通量与土壤温度变化极显著正相关;豌豆地土壤呼吸速率的变化与土壤含水量存在极显著正相关关系,N₂O的排放通量则与土壤温度极显著正相关。5.旱作农田生育期内不同耕作措施的温室效应春小麦生育期内总温室效应表现为NTS>TS>NT>T,豌豆地表现为NTS<TS<NT<T。从三种温室气体相对效应看,CO₂和N₂O均为正效应,CH₄表现为负效应,各处理的温室效应主要表现为CO₂的温室效应。更多还原

【Abstract】 Based on different tillage experiment was implemented in Lijiabu town of Dingxi from Gansu province, an experiment was conducted to study the soil respiration rate , CH₄ and N₂O flux emission rules and influence factors under different tillage measures with rotation in 2010, and attempt to provided a scientific basis to reduce greenhouse gas on dryland farming. The examined tillage treatments were T （Conventional tillage with no straw） , NT（No-till with no straw cover）,NTS（No-till with straw cover）,TS（Conventional tillage with straw incorpo）, and the rotation sequence was spring wheat （w） followed by field pea（p）.The main results showed as follows:1. Growth period variation of soil respiration in dryland farmingThe soil respiration for spring wheat under conventional tillage with no straw（T） and the soil respiration rate for field pea under no-till with straw cover（NTS） were lower than others, which could significantly decrease the soil respiration. The mean values of soil respiration were NTS>TS>NT>T under different tillage in spring wheat, the highest was NTS, the value was 0.2418μmol·m^-2·s^-1,the lowest was T, the value was 0.2036μmol·m^-2·s^-1.In field pea, the mean values of soil respiration were NTS<TS<NT<T, the highest was T, the value was 0.2736μmol·m^-2·s^-1,the lowest was NTS, the value was 0.2181μmol·m^-2·s^-1.2. Growth period variation of CH₄ flux in dryland farmingSpring wheat and field pea were overall atmospheric CH₄ sink under different tillage’s during the growth period, No-till with no straw cover（NT） and No-till with straw cover（NTS） were beneficial for the absorption of CH₄, especially in spring wheat. CH₄ flux under different tillage were NTS>NT>TS>T in spring wheat, the highest was NTS, the value was 0.0818 mg.m^-2.h^-1,the lowest was T, the value was 0.0416 mg.m^-2.h^-1.In field pea, CH₄ flux under different tillage were NT>NTS>T>TS, the highest was NT, the value was 0.0737 mg.m^-2.h^-1,the lowest was TS, the value was 0.0416 mg.m^-2.h^-1.3. Growth period variation of N₂O flux in dryland farmingSpring wheat and field pea were overall atmospheric N₂O source under different tillage’s during the growth period , No-till with no straw cove（NT）, No-till with straw cover（NTS） and Conventional tillage with straw incorpo（TS） could significantly reduce N₂O emissions. In spring wheat, N₂O efflux under different tillage were T>NT>TS>NTS under different tillage, the highest is T, the value was 0.0891 mg.m^-2.h^-1,the lowest was NTS, the value was 0.0461 mg.m^-2.h^-1.In field pea, N₂O efflux were T>NT>NTS>TS under different tillage, the highest was T, the value was 0.1234 mg.m^-2.h^-1,the lowest was TS, the value was 0.0350 mg.m^-2.h^-1.4. Influences factors of greenhouse gas emissions in dryland farmingIn spring wheat, with the increased of the means of soil moisture content and temperature, the soil respiration rate and CH₄ fluxes enlarged, and soil respiration rate were very significantly positive correlation with Soil moisture content in filed pea. And the N₂O emission was positively correlated to soil temperature, especially in field pea.5. Greenhouse Effect on different tillage’s during growth period in dryland farmingTotal Greenhouse Effect in spring wheat showed that: NTS>TS>NT>T,and field pea showed that: NTS<TS<NT<T. The relative effect between CO2 and N₂O showed positive effect, CH₄ showed a negative effect, and greenhouse effect mainly showed that CO2’greenhouse effect.更多还原