以玉米和马铃薯轮作下的复配土为研究对象,设计砒砂岩与风沙土体积比为 0∶1(CK)、1∶5(C1)、1∶2(C2)和 1∶1(C3)的 4种复配农田(复配土),采用碱液吸收法对复配土有机碳的矿化过程进行研究.结果表明:相同复配比的土壤有机碳含量差异无统计学意义,当季种植玉米和马铃薯的复配土有机碳含量较CK的分别提高了27.27%~46.59%、42.47%~70.57%,除种植玉米的 C1 外,差异均有统计学意义(P<0.05);培养过程中,复配土有机碳矿化速率呈现急剧下降、缓慢下降、平稳的 3 个阶段,在培养结束时,均以C3 的降幅最大;复配土有机碳累积矿化量随培养时间的延长呈指数形式上升,当季作物和复配比及互作效应均对有机碳累积矿化量影响显著,种植玉米的C1的有机碳累积矿化量较大,种植马铃薯的则C3的较大;复配土有机碳累积矿化率在 2种作物间的差异较大,种植玉米的C2和种植马铃薯的C1的有机碳累积矿化率较低;复配土有机碳矿化速率常数与半周转期变化趋势相反,种植玉米的C2和种植马铃薯的C1的有机碳矿化半周转期较大.可见,当季作物和复配比均对复配土有机碳矿化产生了影响,玉米和马铃薯轮作以砒砂岩与风沙土体积比 1∶2 较适,可作为一种生产实践助推毛乌素沙地的生态化发展.
Taking compound soil under maize and potato rotation as the research objects,four sets of compound farmlands(compound soil)with soft rock to aeolian sandy soil were designed with their volume ratios of 0∶1(CK),1∶5(C1),1∶2(C2)and 1∶1(C3).The mineralization process of organic carbon in compound soil was investigated using the alkali absorption method.The results showed that there was no statistically significant difference in soil organic carbon contents for the same compound ratio,and the organic carbon contents of the compounded soil planted with maize and potato in the current season were increased by 27.27%to 46.59%and 42.47%to 70.57%compared to that of the CK,respectively,and the differences were statistically significant(P<0.05),except for the C1 planted with maize.The rate of organic carbon mineralization in the compound soil during the incubation showed three stages of sharp decline,slow decline and plateau,all of which were greatest at the end of the incubation for C3.The cumulative mineralization of organic carbon in the compounde soil increased exponentially with the extension of incubation time,and the crop of the season and the compound ratio as well as the intercropping effect all had a significant effect on the cumulative mineralization of organic carbon,which was greater in C1 for maize cultivation and in C3 for potato cultivation.The cumulative organic carbon mineralization rates of the compounded soils varied considerably between the two crops,with lower cumulative organic carbon mineralization rates in C2 for maize and C1 for potatoes grown.The organic carbon mineralization rate constants of the compounded soils showed the opposite trend to the half turnover period,with C2 for maize and C1 for potato planted having larger half turnover periods for organic carbon mineralization.It could be seen that both the crop of the season and the compound ratio affected the organic carbon mineralization of the compound soil,and the rotation of maize and potato with the volume ratio of soft rock to aeolian sandy soil of 1∶2 was more suitable,which could be used as a production practice to help promote the ecological development of the Mu Us sandy land.