不同植烟年限对土壤团聚体稳定性的影响及其相关因素分析

通过野外调查、取样和室内分析,对凉攀地区不同植烟年限的土壤团聚体稳定性及其有机碳含量等相关影响因素进行研究。结果表明:水稳性团聚体在植烟0~5 a期间被显著破坏,红壤、紫色土和水稻土团聚体MWD值分别下降68%、64%和52%;非水稳性团聚体的破坏集中在植烟3~5 a期间,3种土壤团聚体MWD值依次分别下降31%、9%和17%。有机碳含量影响团聚体水稳定性,尤以水稻土和紫色土表现显著。有机碳主要分布在5 mm和0.25 mm粒径团聚体中,随植烟年限的增加,紫色土和水稻土各粒径团聚体有机碳含量显著降低,且5 mm和0.25 mm粒径团聚体下降最明显,各粒径团聚体中有机碳分布越均匀。烤烟不宜连作,连作紫色土和水稻土烟地(田)可增施有机肥,保护土壤团聚体。

Effects of Different Tobacco Cropping Years on Soil Aggregate Stability and Its Influential Factors

This paper studied the changes of soil aggregate stability and organic carbon in different tobacco cropping years and their influential factors in Liangshan and Panzhihua of Sichuan Province through field sampling and laboratory analysis. The results showed that water-stable aggregates were significantly damaged during in period of 0-5 years of tobacco cropping, the MWD of soil aggregates in red soil, purple soil and paddy soil decreased by 68%, 64% and 52%, respectively. Meanwhile, the destruction of the water unstable aggregates was concentrated in the period of 3-5 years of tobacco cropping, and the MWD of the soil aggregates in red soil, purple soil and paddy soil reduced by 31%, 9% and 17%, respectively. The content of organic carbon affected on the water stability of soil aggregates, especially in paddy soil and purple soil. Organic carbon was mainly distributed in aggregates with sizes of >5mm and < 0.25mm. With the increase of tobacco cropping year, the contents of organic carbon were significantly decreased in purple soil and paddy soil, especially in aggregates with sizes of >5mm and < 0.25mm, and organic carbon was distributed more uniformly in different size aggregates. It proves that continuous tobacco cropping is harmful to soil aggregation and accumulation of organic carbon, and organic fertilizer should be applied to protect and improve soil aggregation in purple soil and paddy soil.