不同还田方式下甘蔗叶腐解及养分释放特征研究

摘要

Net bags which simulated straw returning to field were employed to determine characteristics of de -composing and nutrients releasing of carbon ,nitrogen,phosphorus and potassium of sugarcane leaves under different ways returned to field .The results showed that sugarcane leaves had fast decomposing speed during 0 to 60 days under different ways returned to field .Under covered with soil ,covered with soil and plastic film and covered with plastic film only,the accumulated decay rate was 95.1%,94.6%and 82.1%respectively at the 180th day,and was ranked as:covered with soil >covered with soil and plastic film >covered with plastic film only .Releasing speed of nutrients of sugarcane leaves ranked as:potassium>phosphorus>nitrogen≈carbon .The accumulated releasing rate of carbon , nitrogen,phosphorus and potassium was 83.0%-95.0%,82.0%-95.1%,73.5%-97.0%,98.4%-99.7%respec-tively.We could reduce the content of potassic fertilizer in base manure consideration of nutrients releasing .Relea-sing speed of nutrients of sugarcane leaves was grate when we covered with soil or soil and plastic film ,and they did not have a significant difference .Covered with plastic film could keep soil moisture and reduce weed growth .So we suggested using the way of covered with soil and plastic film when we returned sugarcane leaves to field .%为了探明甘蔗叶在土壤中腐解及养分释放特征，应用网袋法模拟秸秆还田方式，研究了不同还田方式下甘蔗叶碳、氮、磷、钾养分的释放特征。结果表明：不同还田方式下，甘蔗叶在0～60 d腐解速度较快，在180 d时，覆土、覆土覆膜和仅覆膜处理下甘蔗叶的质量累积减少率分别为95．1％，94．6％，82．1％，表现为覆土＞覆土覆膜＞覆膜。腐解过程中甘蔗叶养分的释放速率表现为K＞P＞N≈C。180 d，碳、氮、磷、钾的累积释放率分别为83．0％～95．0％，82．0％～95．1％，73．5％～97．0％，98．4％～99．7％。考虑甘蔗叶还田养分的释放情况，可以适量减少基肥中钾肥的用量，覆土处理下，养分释放率最高，但是与覆土覆膜处理差异并不显著，覆地膜可以保持土壤水分、抑制杂草生长，因此，如果生产实际情况允许建议甘蔗叶还田采用覆土覆膜方式。