水田建设对不同类型土壤养分和碳固持的影响

Effects of Paddy Field Construction on Nutrient and Carbon Sequestration in Different Types of Soil

为评估土地利用方式的改变对不同类型土壤养分及固碳的影响,以大西安河岸周边3种典型土壤类型土、新积土、黄绵土为研究对象,分析了水田建设对不同类型土壤的养分含量和碳固持的影响。结果表明:改水田后,3种土壤类型的颗粒组成变化不大;在0~60 cm土层,与改水田前相比,新积土、黄绵土有效磷含量分别显著减少41.2%、46.5%,速效钾含量分别显著减少22.8%、16.9%;土有效磷、速效钾含量分别显著增加70.3%、32.4%;新积土、土、黄绵土全氮、总有机碳含量分别显著减少17.1%~32.9%、16.1%~39.3%;新积土、黄绵土总碳含量分别显著减少7.6%、28.6%,土显著增加13.9%,即改水田后土的碳固持能力得到提升。综上,在土上进行旱地或未利用地改水田更有利于土壤养分及固碳能力的提高。

In order to evaluate the effect of land use change on soil nutrient and carbon sequestration,three typical soil types of lou soil,alluvial soil and loessial soil surrounding the Great Xi’an River were studied to analyze the effects of paddy field construction on the nutrient contents and carbon retention of different soil types. The results showed that the grain compositions of the three soils did not change much after the paddy field was constructed. In the 0—60 cm soil layer,compared with before paddy field,the contents of available phosphorus in the alluvial soil and the loessial soil decreased significantly by 41. 2%and 46. 5%,available potassium contents decreased by 22. 8% and 16. 9%,respectively; available phosphorus and available potassium contents in the lou soil increased significantly by 70. 3% and 32. 4%,respectively; the contents of total nitrogen and total organic carbon in the three soils decreased by17. 1% —32. 9% and 16. 1% —39. 3% respectively,and total carbon contents of the alluvial soil and the loessial soil decreased significantly by 7. 6% and 28. 6%,while that of the lou soil increased by 13. 9%,which indicated that the carbon retention capacity of the lou soil was improved after the construction of paddy field. In conclusion,either dry land or unutilized land for paddy field construction on the lou soil was more conducive to the improvement of soil nutrient and carbon sequestration.