Effects of Amelioration of Saline Soil Through Planting Medicago Sativa L on Soil microbial Activity and Soil Nutrients

27 Mar Effects of Amelioration of Saline Soil Through Planting Medicago Sativa L on Soil microbial Activity and Soil Nutrients

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Abstract

为探讨干旱地区种植紫花苜蓿改良盐渍土对土壤微生物生物量及其活性和土壤养分的影响，选择河西走廊黑河流域国 有临泽农场的草甸盐土荒地作为对照，研究了种植紫花苜蓿2、 3、 4年后的改土效果。结果表明：与CK相比，连续种植4年 后，所测定的土壤化学性质和微生物化学性质指标都发生了极显著（P<0.01）的有利变化，电导率下降5.96 mS·cm-1， pH下 降0.25，有机碳增加1.50 g·kg-1，微生物生物量碳增加48.93 mg·kg-1，微生物熵上升0.43%，荧光素二乙酸酯水解率提高10.87 μg·g-1·h-1，碱解氮增加17.37 mg·kg-1，速效磷增加2.87 mg·kg-1，速效钾增加44.93 mg·kg-1。相关分析表明，微生物生物量碳、 微生物熵、荧光素二乙酸酯水解率、碱解氮、速效磷、速效钾与土壤有机碳之间极显著（P<0.01）正相关，相关系数分别为 0.86、 0.80、 0.87、 0.85、 0.79、 0.80，而与电导率之间极显著（P<0.01）负相关，相关系数分别为-0.83、 -0.79、 -0.84、 -0.86、 -0.88、 -0.78。研究认为，种植紫花苜蓿对草甸盐土有显著的改良效果，电导率下降，有机碳含量提高，微生物活性增强， 速效养分含量增加。

English Abstract

The effects of amelioration of saline soils through phytoremediation on the size and activity of soil microbial communities
and soil nutrients were investigated. The study was conducted in a saline soil in dryland conditions at Linze Farm in Linze county in
Hexi Corridor, Gansu province. There were four treatments in the study, an uncropped control, one year planting of Alfalfa, two year
planting of Alfalfa, three year planting of Alfalfa. The results showed that compared to the control, after three years’ planting of
Alfalfa, soil electrical conductivity decreased from 10.64 to 4.68 mS·cm-1, pH from 8.47 to 8.22, while soil organic C increased from
4.88 to 6.38 g·kg-1, microbial biomass C from 69.74 to 118.67 mg·kg-1, microbial quotient from 1.43 to 1.86%, fluorescein diacetate
hydrolysis rate from 13.35 to 24.21 μg·g-1·h-1. Microbial biomass C, microbial quotient, fluorescein diacetate hydrolysis rate,
available N, available P, available K positively correlated with soil organic C (P<0.01), but negatively correlated with electrical conductivity (P<0.01). Consequently, the planting of Alfalfa may be considered a good strategy for saline soil remediation.