绿肥轮作对植烟土壤酶活性与微生物量碳和有机碳的影响

为探讨绿肥作物改良土壤的生态作用,试验以冬闲连作地为对照,在云南曲靖和晋宁烟草种植区,研究了小麦轮作收获后留根茬（20 cm左右）翻压后种植烟草（麦-烟）,紫花苕子收获后留根茬（30 cm左右）翻压后种植烟草（绿-烟）及豆类轮作（豆-烟）收获后根茬及秸秆全部移除地外种植烟草的4种轮作模式,结果表明：绿-烟和豆-烟复种模式下,植烟生长期内根区土壤酶活性（SEA）、土壤微生物量碳（SMBC）及土壤有机碳（SOC）均高于麦-烟复种及冬闲连作地,并且差异达显著或极显著水平;不同复种模式的SMBC、SOC及SMBC/SOC间呈显著相关性,对提高土壤SEA、SMBC与SOC质量分数影响为：绿-烟〉豆-烟〉麦-烟〉冬闲地。研究认为,SEA及SMBC/SOC可作为评价轮作模式影响烟地红壤质量变化的生物学指标。

Effect of green manure rotation soil enzyme activities and soil microbial biomass carbon and soil organic carbon in tobacco field

In the tobacco growing regions in Yunnan,cultivated lands were usually used to grow wheat,light purple sweet potato leaves（green manure）,beans,vegetables and other crops in the fall and winters and grow tobacco in summers.To investigate the effect of green manure on the improvement of soil ecological environment,four rotation modes： wheat-tobacco,green-tobacco,beans-tobacco,were tested in Qujin and Jinning as compared with the mode of no-planting in the winter mode with aiming at investigating effects of different tobacco rotation modes on the content of soil enzyme activities（SEA） and organic carbon（SOC） and micro-biomass carbon（SMBC） in the soil within tobacco root regions.Results showed that contents of SEA and SOC or SMBC in the soil for the Green-tobacco and beans-tobacco modes were significantly higher than those for wheat-tobacco,and no planting in the winter modes.It was also found that the content of SOC and SMBC was related to the ratio of SMBC to SOC for all modes,the green-tobacco and beans-tobacco modes were favorable for increasing contents of SOC and SMBC and lasting the activation of soil,contents of SMBC were peaked in the tobacco ripe period for the green-tobacco and beans-tobacco modes and peaked in the fast growing period for other modes.The effects of different mode on the SEA and SOC and SMBC ranked in the order from strong and weak as： green-tobacco,bean-tobacco,wheat-tobacco,no planting in winters.A conclusion can be drawn that the content of SEA or SMBC/SOC can be regarded to be an indication to evaluate soil biological environment for the growing of tobacco.