长期施肥对红壤性水稻土颗粒有机质和矿物结合态有机质含量与化学组成的影响

Effects of Long-term Fertilization on Contents and Chemical Compositions of Particle and Mineral-combined Organic Matter in Red Paddy Soils

以江西红壤地区双季稻田肥料定位试验为依托,研究了不施肥(CK)、单施化肥(NPK)及3种不同比例有机无机肥配施(LM、MM、HM)对红壤性水稻土全土、颗粒有机质(POM)和矿物结合态有机质(MinOM)组分碳、氮含量及其化学结构的影响。结果表明:施肥处理全土、POM和MinOM组分中有机碳、全氮含量均显著高于CK处理(P<0.05);与CK处理相比,施肥提高了POM组分质量分布,其中中、高量有机肥配施(MM、HM)分别显著提高POM组分质量分数15.7%和25.1%;施肥处理POM有机碳对土壤有机碳贡献率显著增加13.4%~42.6%;施肥处理未显著影响全土和MinOM组分碳氮比,但显著降低了POM组分碳氮比,降低量为16.8%~25.0%。与NPK处理相比,有机无机配施处理显著提高POM-C/MinOM-C值27.7%~70.2%,提高了土壤有机质活性。红外光谱分析显示,施肥处理较CK处理分别提高全土烷基碳和芳香碳相对含量5.4%~33.2%和0~12.2%;而施肥处理提高了POM烷基碳含量并降低了其芳香碳含量,但几乎不影响POM羧基碳含量,其中MM、HM处理POM烷基碳含量分别较CK处理显著提高12.4%和40.6%;除NPK处理降低了MinOM烷基碳含量外,施肥均提高了MinOM烷基碳和羧基碳含量并降低了其芳香碳含量,其中NPK处理较CK处理显著提高MinOM羧基碳含量70.8%。研究结果说明施肥能提高供试土壤全土及各土壤组分有机碳、全氮含量,与单施化肥相比,有机无机配施更有利于提高土壤POM数量及其结构活性,改善稻田土壤质量。

Based on the long-term fertilization experiment conducted in a red paddy soil of Jiangxi Province,the effects of different fertilization,including no fertilizer(CK),chemical fertilizer only(NPK),and chemical fertilizer plus organic manure with low,middle and high rates(LM,MM,HM)on carbon and nitrogen contents of soil,particle organic matter(POM)and mineral-combined organic matter(MinOM)of soil fractions and their chemical structures were studied.Results showed that fertilization significantly increased carbon and nitrogen contents(P<0.05)of soil and soil fractions compared with CK treatment.Fertilization also increased the mass distribution of POM,especially under MM and HM treatments,which significantly increased by 15.7%and 25.1%,respectively.On the other hand,compared with CK treatment,fertilization significantly increased the contribution rate of POM to organic carbon by13.4%–42.6%,influenced little on C/N ratios of soil and MinOM,but significantly decreased C/N ratios of POM by 16.8%–25.0%.Furthermore,compared with NPK treatment,the chemical fertilizer plus manure treatments significantly increased POM-C to MinOM-C ratios by 27.7%–70.2%,implying manure application can improve organic matter activities.The infrared spectral analysis revealed that fertilization increased the relative contents of alkyl and aromatic C in soil by 5.4%–33.2%and 0–12.2%,respectively,compared with CK treatment.Fertilization influenced little on the content of carboxyl carbon of POM,increased alkyl C content but reduced aromatic C of POM,among of which,MM and HM treatments significantly increased alkyl C content by 12.4%and 40.6%,respectively.Besides,compared with CK treatment,fertilization increased alkyl and carboxyl C contents of MinOM except alkyl C under NPK treatment,and NPK treatment increased carboxyl C content significantly by 70.8%.These results suggest that fertilization can increase organic carbon and total nitrogen in soil and soil fractions.Combined application of chemical fertilizer with manure is propitious to improve the quantities and structure activities of POM,thus can improve soil quality.