施肥对喀斯特地区植草土壤活性有机碳组分和牧草固碳的影响

通过盆栽试验，研究施肥对喀斯特地区植草土壤不同活性有机碳组分和牧草固碳的影响。试验处理包括CK（不施肥）、 N1 （N 150 mg/kg）、 N2 （N 250 mg/kg）、 N1P1 （P2O5100 mg/kg）、 N2P2 （P2O5150 mg/kg）、 N1P1K1 （K2O 70 mg/kg）、 N1P1K2 （K2O 105 mg/kg）和N2P2K1和N2P2K2。结果表明，与对照（不施肥）相比，施肥处理增加植草土壤有机碳、 微生物量碳和易氧化碳，有机碳日矿化量和累积矿化量以及牧草固碳量。其中N1P1K1处理土壤有机碳和易氧化碳最高，N1P1处理土壤微生物量碳最高，N2P2K1处理土壤可溶性碳最高，N2P2K2处理牧草地上部及根系固碳量、 有机碳日矿化量和累积矿化量均最高。综上，低量氮磷钾肥配施有利于土壤活性有机碳的积累，高量氮磷钾平衡配施牧草固碳效果最佳。

Effects of fertilization on soil active organic carbon and carbon sequestration of forage in Karst region

 The objective of this experiment is to study the effects of fertilization on different fractions of soil active organic carbon and carbon sequestration of forage in Karst region. There were nine treatments, CK (no fertilization), N1(N 150 mg/kg soil), N2(N 250 mg/kg soil), N1P1(P₂O₅ 100 mg/kg soil), N2P2(P₂O₅ 150 mg/kg soil), N1P1K1(K₂O 70 mg/kg soil), N1P1K2(K₂O 105 mg/kg soil), N2P2K1 and N2P2K2 in the experiment. Compared to the control (no fertilization), the contents of organic carbon (SOC), microbial biomass carbon (MBC) and readily oxidizable carbon(ROC) in soils, daily mineralization (DMC) and accumulated mineralization (AMC) of organic carbon in soils, and carbon sequestration by forage under the fertilizer treatments are increased. The N1P1K1 has the highest contents of SOC and ROC in soils, the N1P1 has the highest content of MBC, the N2P2K1 has the highest content of the dissolved carbon, and the N2P2K2 has the highest carbon sequestration by forage and the highest contents of DMC and AMC. Generally, more soil active organic carbon is accumulated in the treatments of low NPK, while more carbon is fixed by forage plant in the treatments of high NPK.