紫花苜蓿播种量对根际和非根际土壤微生物数量及酶活性的影响

Effects of seeding rate on soil microorganism andenzyme activity in the rhizosphere and nonrhizosphere of alfalfa

摘要:

在甘肃绿洲灌区,以当前区域优势品种甘农3号紫花苜蓿为试验材料,采用完全随机设计,设4个播量处理(12.0,16.0,20.0和24.0 kg/hm²),对紫花苜蓿根际与非根际土壤微生物数量及酶活性进行研究,为苜蓿生产实践中选择合理的栽培方式提供科学依据。结果表明:苜蓿根际和非根际土壤细菌、放线菌、真菌数量及脲酶、脱氢酶、碱性磷酸酶活性均随播量增加呈先升高后降低趋势,在播量为20 kg/hm²时,根际和非根际土壤微生物数量及酶活性均最大,且根际高于非根际,土壤微生物数量与酶活性间有一定的相关性,且二者均有明显的季节变化,放线菌,真菌数量及碱性磷酸酶,脱氢酶活性均在9月最大,4月最小;在不同土层,0~20 cm大多高于20~40 cm。综上,在甘肃绿洲灌区苜蓿播量为20 kg/hm2,有利于提高苜蓿根际土壤生物性质。

Abstract:

Alfalfa (Medicago sativa cv.Gannong No.3) was used as the experimental material to study the effect of seeding rates (12.0,16.0,20.0,and 24.0 kg seed/ha) on soil microbes and enzyme activity in the rhizosphere and non-rhizosphere in arid oasis of Gansu Province through a complete random experiment design with three replicates in order to provide the reasonable farming methods for alfalfa production.Results showed that soil microorganism and enzyme activity increased first and then decreased with the increase of seeding rate,and they reached the highest at the seeding rate of 20.0 kg/ha,and they were higher in the rhizosphere than those in the non-rhizosphere.There was a certain correlation between the amount of soil microorganisms and the activity of soil enzymes with obvious seasonal variation pattern.The amount of actinomycetes and fungi,and the activity of alkaline phosphatase and dehydrogenase reached the highest in September and the lowest in April,and they were higher in 0~20 cm layer than those in 30~40 layer.