了解田间施肥措施对南方红壤碳库管理指数的影响具有重要意义,以湖北贺胜桥镇建立19 a的长期施肥试验小区为研究对象,研究了不施肥(CK)、施用有机肥(T1)、施氮磷钾肥(T2)和氮磷钾肥与秸秆配施(T3)4种处理对南方红壤有机碳和碳库管理指数的影响及差异。结果 表明:(1)长期施肥能显著降低土壤容重,显著增加毛管孔隙度、毛管持水量、饱和含水率和pH(p<0.05)。(2)长期施肥显著增加了3个土层土壤中有机碳(SOC)、活性有机碳(LOC)和总碳(TC)以及水溶性有机碳(WSOC)、热水提取碳(HWSC)和颗粒有机碳(POC)等活性有机碳组分含量,尤其是T3处理0—15 cm土层SOC,LOC,TC和POC含量较CK分别提高了78%,62%,113%和241%,且差异性显著(p<0.05); T1处理0—15 cm土层WSOC和HWSC较CK分别增加了21.38 mg/kg和22.07 mg/kg,且差异性显著(p<0.05)。(3)灵敏性指数表明,3个土层中的POC(33.33%～251.52%)、WSOC(5.60%～193.89%)和HWSC(16.32%～147.14%)总体上高于SOC(29%～59%),POC,WSOC和HWSC比SOC更适合作为确定田间管理措施对土壤有机碳影响的指标。碳库管理指数(CMI)与SOC,LOC存在显著(p<0.05)和极显著(p<0.01)正相关关系,CMI能反映土壤有机碳的变化情况。(4)CMI表明,T3(CMI=176.16)>T1(CMI=157.18)>T2(CMI=134.93),本研究中最佳的田间施肥方式为T3。研究结论可帮助优化区域内田间管理措施,改善土壤质量,提高农作物产量与质量。
In order to understand the effect of various fertilization measures on soil carbon and carbon stock management index, the long-term fertilization experiment area established for 19 years in Heshengqiao Town, Hubei Province was studied. The effects and differences of no fertilization(CK), application of organic fertilizer(T1), NPK fertilizer(T2)and NPK fertilizer combined with straw(T3)on soil organic carbon and carbon management indexes were studied. The results show that:(1)long-term fertilization can significantly reduce soil bulk density, significantly increase capillary porosity, capillary water holding capacity, saturated water content and pH(p<0.05);(2)long-term fertilization significantly increased the contents of soil organic carbon(SOC), labile organic carbon(LOC)and total carbon(TC)in the three soil layers, as well as the contents of water soluble organic carbon(WSOC), hot water soluble carbon(HWSC)and particulate organic carbon(POC); the contents of SOC, LOC, TC and POC in the 0—15 cm soil layer treated by T3 increased by 78%, 62%, 113% and 241% compared with CK, and the difference was significant(p<0.05); compared with CK, WSOC and HWSC in 0—15 cm soil layer under T1 treatment increased by 21.38 mg/kg and 22.07 mg/kg, respectively, and the difference was significant(p<0.05);(3)the sensitivity index showed that POC(33.33%～251.52%), WSOC(5.60%～193.89%)and HWSC(16.32%～147.14%)in the three soil layers were generally higher than SOC(29%～59%), and POC, WSOC and HWSC were more suitable indicators to determine the impact of field management measures on soil organic carbon than SOC; there was a significant(p<0.05)and extremely significant(p<0.01)positive correlation between carbon management index(CMI)and SOC and LOC, and CMI could reflect the change of soil organic carbon;(4)meanwhile, according to the CMI value, T3(CMI=176.16)>T1(CMI=157.18)>T2(CMI=134.93), combined with the improvement of soil properties and organic carbon by each fertilization treatment, the best field fertilization method in this study was T3.
