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1.不同刈割期绿肥的鲜草与干草产量有显著差异,苕子现蕾后,黄花苜蓿初荚期后鲜草的增重幅度不大,约为7—9%,但干物质的积累迅速,干草增加34—58%,苕子盛花期和黄花苜蓿结荚成熟后鲜草产量急骤下降,干草产量也略趋降低,因而鲜草产量不能作为绿肥生产率的唯一指标。三年的试验结果,苕子以开花后至盛花前,黄花苜蓿以结荚期,在5月上、中旬刈割为宜。2.绿肥的氮素百分含量随生育期的推迟而下降。有机碳则逐渐增加,因而碳氮比值增大。绿肥的有机质分解和氮素释放速率也因刈割期而异。刈割早,碳氮比小,茎叶比小,有机质分解快,氮素的释放则猛而短。苕子在开花至盛花期,黄花苜蓿在结荚期刈割的,碳氮比(15—16)和茎叶比都较为适中,碳氮释放稳而长。但是绿肥刈割期必须力求与水稻生育相适应,生育期较短的水稻品种,以适当早割,碳氮比以11—14之间的为宜。生育期长则宜适当迟割。3.绿肥刈割迟早对根茬肥效的影响极大。刈割愈迟,茬口愈肥。这是利用绿肥培养地力的重要因素。因而确定绿肥刈割期必须考虑根茬的残效。
The results showed that there was a significant difference between fresh grass and dry grass yield of green manure at different cutting stages. After squash bolting, fresh grass weight gain of young alfalfa after initial podding stage was small, about 7-9%, but dry matter accumulation Rapid, hay increased by 34-58%, flowering floss and flowering alfalfa knot pod mature sharp decline in yield, hay production also slightly reduced, so fresh grass yield can not be used as the only indicator of green manure productivity. Three years of test results, prickly heat to full bloom flowering, Medicago falcata podding period, in May, mid-cutting is appropriate. 2. Nitrogen content of green manure decreased with the delay of growth period. Organic carbon is gradually increased, so carbon and nitrogen ratio increased. Organic manure decomposition and nitrogen release rate of green manure vary with the cutting period. Early mowing, small C / N ratio, small stem-leaf ratio, rapid decomposition of organic matter, and nitrogen release are fierce and short. Cotyledons flowering to blooming flowering, Medicago falcata mowing in the pod, carbon and nitrogen ratio (15-16) and stem-leaf ratio are more moderate, stable release of carbon and nitrogen long. However, the green manure mowing period must seek to adapt to rice growth, shorter growth period of rice varieties, appropriate early cut, C / N ratio of 11-14 is appropriate. Long growth period should be appropriate to cut off. 3. Green manure sooner or later on the stubble fertilizer effect greatly. Clipping later, stubble more fat. This is the use of green manure fertility important factor. Thus to determine the green manure cutting must consider the stubble residual effect.