播种方式对人工草地土壤有机碳氧化稳定性和化学结合形态的影响

Effects of sowing methods on the oxidation stability and the chemical bound forms of soil organic carbon in artificial grassland

采用分层取样法研究了两年生单播紫花苜蓿、单播无芒雀麦、隔行混播和同行混播人工栽培草地土壤有机碳氧化稳定性和化学结合形态。结果表明,在牧草生长时期,0～40 cm土壤有机碳含量以单播紫花苜蓿草地最高,其次为隔行混播草地,二者与单播无芒雀麦草地、同行混播草地间差异极显著(P<0.01);有机碳氧化稳定系数以隔行混播草地最大(1.27),同行混播草地次之(1.16),二者与单播紫花苜蓿草地(0.99),单播无芒雀麦草地(0.94)间差异极显著(P<0.01),说明混播有利于土壤有机碳的稳定;有机碳化学结合方式上均以铁铝键结合为主,各处理不同层次铁铝键结合有机碳均极显著高于钙键结合有机碳(P<0.01)。

A stratified sampling method was used to study the oxidation stability and the chemical forms of soil organic carbon（SOC） for two-year old alfalfa,for Bromus inermis,and for a mixture of the two.SOC of the alfalfa only was the highest at 0-40 cm,followed by the interlaced mixture.There was a highly significant difference（P〈0.01） compared with the single B.inermis and with the mixture components in the same line.Coefficient of SOC oxidation stability of the interlaced mixture（1.27） was greater than that of the mixture in the same line（1.16）.There was a highly significant difference（P〈0.01） compared with the single alfalfa（0.99） and the single B.inermis（0.94）.It showed that the mixture was beneficial to the oxidation stability of SOC.The chemical bondings of SOC were mainly in the forms of Fe（Al）-bound and under different treatments and at different layers,the content of Fe（Al）-bound SOC was higher than that of Ca-bound SOC（P〈0.01）.