大机械作业对黑土区耕地土壤三相比与速效养分的影响

通过对收获和深松整地机械作业前后典型黑土区耕地土壤的三相比、速效N、P、K含量的测定和分析,揭示了机械作业对三相比与速效养分的影响,对科学指导机械作业、解决黑土资源的保护与开发利用之间的矛盾具有重要意义.研究结果表明:(1)将土壤三相作为一个有机整体置于二维三系图中分析土壤结构性状是探讨土壤三相比的一种新的、有效的方法手段,可以直观看出机械作业下土壤三相比的变化情况以及向理想结构逼近的趋势特征.(2)大机械作业后上层耕作区土壤三相比大幅逼近理想状态,对耕作区土壤结构的改良作用明显优于中机械作业,但大、中机械作业后下层非耕作区均表现出不同程度的积累压实作用.(3)大机械作业可以显著增加土壤速效磷的含量,提高幅度范围为20.07%～380.91%,并以深松作业对表层耕作区的影响最大.大、中机械作业均增加了土壤速效钾的含量,提高幅度分别为10.04%～20.61%和17.05%～27.52%.与速效磷和速效钾相比,土壤速效氮对机械作业的反应不敏感,除中机械作业对下层非耕作区的影响外,其余差异均未达到显著水平.

Effect of Heavy Machinery Operation on Soil Three Phases and Available Nutrient in Phaeozem Region

Based on typical black soil in northeast of China,the proportion of soil solid-liquid-gaseous phase and the concentration of soil available nitrogen, phosphorus,potassium were measured after machinery harvesting and subsoiling.The effect of heavy machinery operation on soil three phases and available nutrient were revealed,it could provide scientific basis for guiding machinery activities and sustainable utilization of black soil resources.The results showed that:(1)It was a new and effective analysis method for soil structure to put soil solid-liquid-gaseous phase in a two-dimensional-three-phase diagram.The variety of three phases and trend to optimal structure would be shown intuitively.(2)The field operated by heavy machinery inclined to the ideal structure intensely.Heavy machinery operation ameliorated soil three phases more distinctly than medium machinery in topsoil.There is an contrary action in subsoil.The soil three phases were far from the optimal structure point because of various soil compaction.(3)Heavy machinery operation could increased the available phosphorus content significantly,especially after subsoiling in topsoil,and the improvement scope was 20.07%~380.91%.The concentration of soil available potassium both heightened after heavy and medium machinery operation,with different increase scope: 10.04%~20.61% and 17.05%~27.52% respectively.Soil available nitrogen was not sensitive to machinery operation,T test showed that the differences were insignificant except for medium machinery in subsoil.