机械压实对蔗田土壤理化性状、微生物活性和甘蔗生长的影响

Effects of Mechanical Compaction on Physicochemical Properties,Microbial Activity of Sugarcane Fields Soil and Growth of Sugarcane

【目的】探明机械车轮碾压引起的土壤压实对蔗田理化性状、微生物活性和甘蔗生长的影响,为保护蔗田土壤环境和甘蔗机械化收获的推广提供理论依据。【方法】采用随机区组设计,用甘蔗田间运输车对蔗田进行碾压处理,以未碾压的小区作为对照。在宿根蔗的不同生长期调查土壤容重、含水量、土壤养分、酶活性和微生物量,以及甘蔗根系、农艺性状和产量等参数。【结果】机械压实后土壤容重增大,土壤含水量、土壤pH值、土壤有机质以及全氮、全磷和全钾含量有所提升,速效养分含量降低;土壤蔗糖酶的活性显著提高,土壤脲酶活性和磷酸酶活性无显著变化;土壤细菌、真菌、放线菌的数量总体上比CK高;甘蔗植株的根系干重显著下降,发株数显著减少,蔗茎减产7.43%。相关分析结果表明,脲酶活性与真菌数量呈正相关关系、与放线菌数量呈负相关关系;蔗糖酶活性与真菌数量呈正相关关系;磷酸酶活性与真菌数量呈负相关关系,与放线菌呈正相关关系。【结论】机械压实可在一定程度上提高土壤含水量、土壤基础肥力和土壤微生物活性,而土壤有效养分的供给能力有所下降;同时,压实可抑制甘蔗根系生长,进而影响甘蔗产量。

【Objective】To provide a theoretical basis for the protection of soil environment in sugarcane field and popularization of mechanized harvest of sugarcane,the effects of soil compaction caused by mechanical wheel rolling compaction on the physical and chemical properties,microbial activity and sugarcane growth of the sugarcane field were ascertained.【Method】The randomized block design was used in the experiment.The sugarcane field was rolling compacted by transporter,the uncompacted field was control treatment.Soil bulk density,moisture content,soil nutrient,enzyme activity and microbial biomass,root system,agronomic traits and yield of sugarcane were investigated at different growth stages of stubble cane.【Result】After compaction,soil bulk density,moisture content,pH value,organic matter,total nitrogen,total phosphorus and total potassium content increased,and the content of available nutrients decreased;the activity of invertase in soil was significantly increased and there was no significant change in soil urease activity and phosphatase activity;in the mass,the amount of bacteria,fungi and actinomycetes in the soil was higher than that in the control group;dry weight of sugarcane root system decreased significantly,the number of germinating sugarcane was significantly reduced,production of sugarcane stem was reduced by 7.43%.The results of correlation analysis showed that the activity of urease was positively correlated with the number of fungi and negatively correlated with the number of actinomyces.There was a positive correlation between sucrase activity and fungal number.Phosphatase activity was negatively correlated with the number of fungi and positively correlated with actinomycetes.【Conclusion】Under the soil condition of this experiment,mechanical compaction can improve soil moisture content,basal fertility and microbial activity to a certain extent,while the supply capacity of soil available nutrients is reduced.Meanwhile,compaction can inhibit the growth of sugarcane root system,and then affect the yield of sugarcane.