Carbon dioxide circulation to harmonize global environmental aspect with crop production

为了从农业方面为防止全球变暖进程做出贡献，我们于1995年12月至1996年8月在一个由耕作方式(两层；常规耕作（CT) /免耕作（NT）） x耕作方式（三层；单作/单作/混作）x除草处理（除草/免除草）x重复（三层）组成的农田上进行了因子试验，并测量了土壤呼吸速率。从试验结果来看，(1)单作杂草的干物质产量大于混作，NT小区的产量大于CT小区。(2)玉米、大麦、小麦第一次和第三次种植时，玉米、高粱、玉米第二次种植时，玉米、玉米叶片和茎干物质产量均高于玉米、玉米第一次和第三次种植时的干物质产量。(3)在谷物干物质产量方面，第一次和第三次播种时，排在第一、第二和第三位的分别是“除草”、“除草”和“不除草”。(4)从总干物质产量及其转化值计算植物固定二氧化碳，NT地块与CT地块间差异不显著。我们比较了森林中所有植物的固定二氧化碳值和一种落叶乔木的固定二氧化碳值。计算结果表明，免耕和混作对农田土壤的固定作用显著。(5)在土壤呼吸速率的测量中，在作物生长期，NT样地与CT样地之间没有差异，但在无作物季节，NT样地的值大于CT样地。

With an aim of contributing from agricultural side to prevent the progress of global warming, we carried out the factorial experiment on a field composed of tillage method (two levels ; conventional tillage (CT) / no-tillage (NT)) x cropping style (three levels ; single cropping/ single cropping/ mixed cropping) x treatment of weeding (weeding/ no-weeding) x repetition (three plots), and measurement of soil respiration rate on a field from December in 1995 to August in 1996.From the experimental result, (1) The dry matter yield of weed in single cropping was more than that in mixed cropping, and the yield in NT plot was more than that in CT plot. (2) The dry matter yield of leaf and stem of crops in CT plot was more than that in NT plot at the first and the third croppings in case of barley and wheat, but the yield in NT was more than that in CT plot at the second cropping in case of sorgo and corn. (3) In dry matter yield of grain, the first, the second and the third in order were "weeding", "weeding" and "no weeding", respectively, at the first and the third croppings. (4) In fixed carbon dioxide by plants calculated from the total dry matter yield and its conversion value, there was no notable difference between in NT plot and in CT plot. We compared the values of fixed carbon dioxide by all plants and the value of fixed by a deciduous trees in forest. From the calculated results, the notable effect of fixation by plants produced in no-tillage and mixed cropping on a field was shown. (5) In the measurement of soil respiration rate, there was no difference between in NT plot and in CT plot during crop growing period, but the value in NT plot was larger than that in CT plot during season without crop on a field.