不同耕作方式对广西地区甘蔗地土壤热性质的影响

Thermal Property of Soil at Sugarcane Fields in Guangxi Affected by Tillage Method

【目的】探讨不同耕作方式下甘蔗地土壤热性质的动态变化,为合理有效利用水热资源提供依据。【方法】在广西农业科学院里建甘蔗种植地进行研究,定位监测粉垄耕作(T)处理和免耕(NT)处理方式下,5、20和40 cm深度土层的土壤含水量和土壤温度,并结合土壤基本参数,分析2个处理下土壤温度、土壤热导率和土壤热通量的变化规律。【结果】NT处理受其质地影响,土壤温度的分布为5 cm>40 cm>20 cm,差异均显著(P<0.05,下同);T处理在一定程度上影响了土壤质地,其土壤温度分布为5 cm>20 cm>40 cm,差异均显著。研究期内,T处理土壤热导率在20 cm以上土层高于NT处理。T处理有利于降水入渗、储水性能良好、下层水分可供给上层等效果,相比于NT处理改善了土壤热导率沿土壤剖面的分布。同时,不同降水条件下,处理间的土壤热通量变化相同:NT处理在5~20 cm层大于T处理,而在20~40 cm层小于T处理,差异均达到显著水平。说明T处理土壤热通量由上至下减小,变化规律明显;而NT处理上下层间波动较大。【结论】粉垄耕作处理相比于免耕处理,在一定程度上改善了本地区的土壤质地和土壤温度分布,土壤热导率和土壤热通量的变化更具稳定性和规律性,可作为广西地区农业种植和管理方式的参考。

【Objective】The hydrothermal dynamics of soil at sugarcane fields in Guangxi province was studied under different tillage methods to provide information for effective utilization of the natural resource.【Method】The moisture content and temperature of soil in the depths of 5,20 and 40 cm under two tillage methods were monitored.Smash-ridging tillage(T)and no-tillage(NT)were applied in the sugarcane field at Lijian Research Station of Guangxi Academy of Agricultural Sciences in Nanning.In addition to the basic properties,the temperature,thermal conductivity,and heat flux of the soil under the treatments were collected for analysis.【Result】The texture of the NT-treated soil invariably affected the temperature distribution at different depths to show it from high to low in the order of 5 cm>40 cm>20 cm with significant differences at P<0.05(same level for the following).Whereas,when T was applied the texture was altered to cause the temperature ranking changed to 5 cm>20 cm>40 cm.During the time of this study,the thermal conductivity of the 5 cm and 20 cm soil under the T treatment was higher than that under NT.Compared to NT,T provided advantages on the infiltration,storage,and improved water distribution in the soil,leveling the thermal conductivities in various layers.Furthermore,varied precipitation significantly affected the heat flux in the 5-20 cm layer under NT more than T but less in the 20-40 cm layer.It indicated that the heat flux in the T-treated soil decreased gradually from the top to the deeper layers.On the other hand,in the NT-treated soil,it fluctuated greatly between the upper and lower layers with varied rain falls.【Conclusion】The smash-ridging tillage improved the texture and temperature distribution of the soil in the tested range with a more constant and predictable thermal conductivity and heat flux over no-tillage method.