施肥对喀斯特地区植草土壤碳库管理指数及酶活性的影响

为了解施肥对喀斯特地区土壤有机碳积累及平衡的影响,通过田间试验,研究不同施肥处理对植草土壤活性有机碳含量、碳库管理指数及土壤酶活性(淀粉酶、蔗糖酶和脲酶)的影响。结果表明,施肥对植草土壤活性有机碳和碳库管理指数的影响显著,但是对3种土壤酶活性的影响不一致。与不施肥相比,施肥提高土壤活性有机碳和碳库管理指数,以N₂PK处理提高土壤活性有机碳含量最为明显,提高幅度达到695.6%;低N(N₁)处理提高土壤淀粉酶活性8.65%~13.80%,而高N(N₂)处理提高土壤淀粉酶则不明显,且N₂P处理降低17.94%;各施肥处理土壤蔗糖酶活性降低2.55%~26.97%;单施氮肥和N₂P处理提高土壤脲酶活性87.67%~169.03%,而N₁P处理降低土壤脲酶活性。研究结果可为喀斯特地区牧草科学施肥及农田固碳减排提供理论依据。

Effects of fertilization on soil carbon pool management index and enzyme activities in pasture grown soil of the Karst region

To understand the effect of fertilization on accumulation and balance of soil organic carbon in the Karst region,the effects of different fertilization treatments on the labile organic carbon content,carbon management index and enzyme activities (amylase,invertase and urease) in pasture grown soil were investigated in a field experiment. Fertilization had significant effects on the labile organic carbon and carbon management index,but affected the activities of three enzymes in the soil differently. Compared to no fertilization,soil labile organic carbon and carbon management index were increased under fertilization,and soil labile organic carbon content increased (695.6%) significantly under the N₂PK treatment. Soil amylase activities were increased by 8.65%-13.80% under low N treatment,but not obviously different under high N treatment. They were reduced by 17.94% under the N₂P treatment. Soil invertase activities were decreased by 2.55%-26.97% under fertilization treatments. Soil urease activities were increased by 87.67%-169.03% under N only and N₂P treatments,but decreased under the N₁P treatment. The results provide a theoretical basis for scientific fertilization and the reduction of farmland carbon emission in the Karst region.