中文摘要：

土壤呼吸是碳循环的重要环节,为探讨垄作和覆盖对旱三熟蚕豆田土壤呼吸的影响,测定了平作（T）、垄作（R）、平作＋半量覆盖（TS1）、垄作＋半量覆盖（RS1）、平作＋全量覆盖（TS2）、垄作＋全量覆盖（RS2）6种处理下的西南紫色土丘陵区蚕豆/玉米/甘薯旱三熟体系中蚕豆生长季节的土壤呼吸变化,分析了蚕豆田碳平衡特性。结果表明,蚕豆生长季节农田土壤呼吸随作物生长一致,呈先增加后减弱的变化趋势,变化范围为0.885~10.213μmol/（m~2·s）。全生育期平均土壤呼吸速率差异显著,表现为TS2〉RS2〉RS1〉TS1〉T〉R;分别为4.096,3.780,3.441,3.104,2.850,2.439μmol/（m~2·s）,较平作不覆盖处理增加了43.7%,32.6%,20.7%,8.9%,-14.4%。垄作显著降低了蚕豆农田土壤呼吸速率,而秸秆覆盖显著提高土壤呼吸速率,且随着覆盖量的增加而增加。不同生育阶段土壤呼吸总量存在差异,表现为成熟期〈苗期〈鼓粒期〈分枝现蕾期〈开花结荚期,其中开花结荚期约占50%;利用根排除法测得蚕豆田根系呼吸占土壤呼吸比例变幅为19.49%~54.23%,利用回归分析法测得结果为37.02%~60.64%,二者均值分别为38.62%和49.12%。不同耕作和覆盖处理下蚕豆田整个生长季均表现为碳汇,净碳汇为857.26~2236.25kg/hm~2。与平作不覆盖相比,RS2、TS2、RS1、TS1、R分别较平作不覆盖处理T高出160.86%,101.44%,30.78%,47.63%,110.41%,差异达显著水平。试验结果表明垄作和秸秆覆盖有利于蚕豆田生态系统的碳汇,以垄作＋全量覆盖的效果最好。

英文摘要：

Soil respiration is an important process in carbon cycling. This study investigated effects of two tillage practices （ridge tillage and traditional tillage） and straw mulching at 0, 3750, or 7500 kg straw dry matter/ ha on soil respiration of lava bean farmland. Six treatments applied were： traditional tillage without straw mulching （T）, ridge tillage without straw mulching （R）, traditional tillage＋straw mulching at 3750 kg/ha （TS1）, ridge tillage＋straw mulching at 3750 kg/ha （RS1）, traditional tillage＋straw mulching at 7500 kg/ha （TS2）, and ridge tillage＋straw mulching at 7500 kg/ha （RS2）. Soil respiration properties and carbon balance in dry-cropped farmland with a triple intercropping system of lava bean, maize, and sweet tomato were evalua- ted during the crop growth period, in a region of southwest China known as the purple hilly region. This study identified seasonal changes in soil respiration rate reflecting crop growth, with a peak in the middle of the fava bean growth cycle, and with a range from 0. 885--10. 213 μmol/（m2 · s） in cropped soils, respectively. The soil respiration rates of the different treatments ranked TS2 〉RS2〉RS1〉TS1〉T〉R [-4. 096, 3. 780, 3. 441, 3. 104, 2. 850, 2. 439 μmol/（m2 · s）, respectively]. Ridge tillage reduced soil respiration in fava bean farmland, whereas straw mulching treatment resulted in increased respiration corresponding to straw mul els. In soil planted with fava bean, the respiration rate at different crop growth stages ranked ripeni ching levng〈seedling〈seed filling 〈branching〈 flowering and podding. Soil respiration during flowering, filling and podding stages contributed 50 % of the total soil respiration. The contribution of root respiration to total soil respiration was 49.12% （range 37. 02%- 60. 64%） when measured by a root biomass regression equation, but was 38.62% （range 19.49%-52.3%） when measured during the life cycle of the lava bean crop with a by root exclusion. The farmland sy