长江下游稻麦轮作区机收对土壤扰动的影响特征

Effects of harvester on soil disturbance in rice-wheat rotating areas in the lower reaches of Yangtze River region

[目的]本文旨在获取长江下游稻麦轮作区水稻与小麦机收环节的土壤扰动信息,评价该区在全程机械化条件下各机械化作业环节对土壤系统的影响。[方法]于该区连续开展3个作物季的田间调查,结合贯入阻力和微地貌测试,同时辅以取样法监测土壤含水率及容重。[结果]综合微地貌测试仪、土壤紧实度仪及土壤取样等方法获得的多维度土壤物理指标能够准确反映出中小型稻麦联合收割机对土壤的影响。水稻机收环节的微地貌破坏严重,麦收环节机械对土壤的破坏显著降低。收割机并不造成耕作层土壤容重显著变化,表明稻作制的机械-土壤关系特殊。基于多季、不同作物及不同土层数据的统计分析进一步表明,在该区开展农机安全生产的土壤含水率上限为35%,土壤紧实度下限为1 MPa。履带式中小型收割机造成的土壤压实面积比最低(40%),微地貌破坏能够影响全耕层,因此现有的机械设计准则需要针对稻麦轮作制的区域农业特点进一步修订。[结论]本文组装设计的土壤扰动区域调查方法可为农业智能化农情信息装备的研发提供借鉴,所得的机收土壤扰动结果也可为土壤质量精准管理提供参考。

[Objectives]The purpose of this study was to obtain the soil disturbance information of rice and wheat harvest process in the rice-wheat rotation area in the lower reaches of the Yangtze River delta,and to evaluate how the machinery system affects the soil system.[Methods]A 3 season field investigation was conducted to monitor soil penetration resistance,soil micro-relief and soil physical properties and their response to harvester traffic.[Results]Results showed that multiple-index monitoring of traffic-induced soil changes with profile meter,cone penetrometer and soil sampling effectively quantified soil compaction.Rice harvesting greatly damaged soil microrelief.But this effect was insignificant at the wheat harvesting season.Differed from common findings,harvester traffic in the paddy soils did not induce significant changes of soil bulk density in the tilled soil layer,indicating the protective effect on the soil resources.Multi-season,different crops and multi-layer soil investigation revealed that safe trafficking in the region requires a soil water content no more than 35%,while the lower limit of soil hardness should be 1 MPa.Tracked harvester induced at least 40%soil surface coverage of compaction,with soil microrelief damage reaching plough pan.This would imply that the current theory of machinery design should be revised to adapt to the lower reaches of the Yangtze River where rice-wheat rotation is the major farming system.[Conclusions]The designed method of field survey on machinery-induced soil disturbance can be applied to information agriculture where the information collection layer needs to be designed.Meanwhile the findings of this research provided basis for precision management of soil in the investigated region.