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采用田间试验研究了黄土旱塬区不同覆盖措施下的冬小麦农田土壤呼吸日变化和季节变化特征.试验包括4个处理:作物生育期秸秆覆盖600 kg.hm-2(M600)、秸秆覆盖300 kg.hm-2(M300)、地膜覆盖(PM)和无覆盖处理(CK).结果表明:冬小麦农田土壤呼吸速率从播种至返青之前呈下降趋势,处理间没有显著差异;越冬后土壤呼吸速率迅速提高,至拔节期最高.与CK相比,3个覆盖处理在越冬至成熟期间均显著促进了土壤CO2的释放,其中PM与其他处理间的差异达到极显著水平.全生育期M600和M300处理土壤呼吸速率平均分别为1.47和1.52μmol CO2.m-2.s-1,较CK(1.38μmol CO2.m-2.s-1)分别提高了6.6%和10.2%;PM处理土壤呼吸速率平均为3.63μmol CO2.m-2.s-1,较CK提高了163%.CK处理土壤呼吸日变化呈单峰曲线,峰值出现在12:00左右,秸秆覆盖后峰值时间推迟到14:00左右;PM处理土壤呼吸日变化特征在拔节期与对照相似,在成熟期则呈双峰曲线,峰值分别出现在12:00和16:00左右.土壤呼吸速率与土壤温度和土壤水分分别呈指数和抛物线式相关.
Field experiments were conducted to study the diurnal and seasonal variations of soil respiration of winter wheat farmland under different coverage measures in the Loess Plateau.The test includes four treatments: straw mulching at 600 kg.hm-2 (M600) and straw mulching at 300 kg .Results showed that the soil respiration rate of winter wheat decreased gradually from sowing to rejuvenation, and there was no significant difference between the treatments. The respiration rate of soil after winter was rapidly Compared with CK, the three cover treatments significantly promoted the release of soil CO2 during the winter to maturity period, and the difference between PM and other treatments reached a significant level.M600 and M300 treatments during the whole growth period The average soil respiration rate was 1.47 and 1.52μmol CO 2 -m-2.s-1, respectively, increased by 6.6% and 10.2% respectively compared with CK (1.38μmol CO 2 · m-2.s-1) Was 3.63μmol CO 2 · m-2.s-1, which was 163% higher than that of CK.The diurnal variation of soil respiration during CK treatment showed a single peak curve with the peak value at 12:00 and the postponement peak time postponed to about 14:00 The diurnal variation of soil respiration during PM treatment was similar to the control at jointing stage and was mature The bimodal curve, a peak appeared at 12:00 and 16:00 respiration rate and soil temperature and soil moisture are parabolic and exponential correlation.