Supported by the National Natural Science Foundation of China (No. 41571211) and the University Research Key Projects of Hunan Province in China(No. 15A085)
利用具有35a的长期定位试验，在保证原定位试验继续正常开展的前提下，将原化肥处理改施有机肥，原有机肥处理改施化肥或增施有机肥，分析增减施有机肥后耕层土壤团聚体稳定性总有机碳（TOC）及其组分和铁铝氧化物的变化与作用关系，探究胶结物对红壤性水稻土团聚体稳定性变化的影响。结果表明：化肥（CF）及常量有机肥（NOM）处理增施有机肥后，团聚体平均重量直径（MWD）变化不明显，易氧化有机碳（EOC）分别升高87.44%和20.53%；高量有机肥（HOM）及NOM处理减施有机肥后，MWD分别显著降低8.39%和6.80%，高改化（H-C）处理的TOC、轻组有机碳（LFOC）及粗颗粒态有机碳（cPOC）含量显著降低，而常改化（N-C）处理的TOC及其组分变化不明显。无论增施还是减施有机肥，铁铝氧化物含量的变化规律不明显。相关及结构方程模型分析表明，大于0.25 mm团聚体含量是影响团聚体稳定性的唯一直接影响因素；影响MWD及大于0.25 mm团聚体含量的效应系数由大到小依次为：易氧化有机碳、轻组有机碳、游离氧化铁、络合态铁。因此，大于0.25 mm大团聚体在红壤性水稻土的团聚体稳定性中发挥主导作用，有机碳活性组分对大团聚体的形成与破坏具有重要影响。
[Objective] This paper is oriented to explore effects of increased or decreased application of organic manure on stability and cement (e.g. organic carbon and iron-aluminium oxides) of soil aggregates stability in red paddy soil of a long-term field fertilization experiment.[Method] In the 35-year-old long term field experiment, on the premise of guaranteeing normal development of the original stationary experiment, the treatments, which used to be applied with chemical fertilizer, changed to be applied with organic manure instead and the treatments, which used to be applied with original manure, changed to be applied with chemical fertilizer or remained to be applied with organic manure, but at a higher rate. Soil samples were collected from the tillage soil layers of the treatments and analyzed for changes in fractionation, stability, contents of total organic carbon (TOC) and its fractions, and content of iron-aluminium oxides of soil aggregates. Based on the analysis of the relationship between aggregates stability and cement, mechanism of their interactions was explored with correlation analysis and path analysis methods.[Result] Results show that there was no obvious changes in average weight diameter (MWD) of the soil aggregates after application of organic manure at a higher rate in Treatment CF (application of chemical fertilizer) and Treatment NOM (application of organic manure at a normal rate), but there were in content of oxidizable organic carbon (EOC), which increased by 87.44% and 20.53%, respectively, in the organic carbon fraction, and in content of fine particulate organic carbon (fPOC), which increased by 26.94%, in Treatment N-H (treatments changed from normal to high in organic manure application rate); MWD decreased significantly or by 8.39% and 6.80%, respectively, in Treatment H-C (treatment changed from application of organic manure at a high rate to application of chemical fertilizer) and treatment N-C(treatments changed from application of organic manure at a normal rate to application of chemical fertilizer); TOC, coarse particulate organic carbon (cPOC) and light organic carbon(LFOC) decreased by 23.48%, 30.09% and 25.29%, respectively, in treatment H-C (treatment changed from application of organic manure at a high rate to application of chemical fertilizer), but TOC and its fraction did not vary much in Treatment N-C (treatment changed from application of organic manure application of chemical fertilizer treatment); and no matter whether in treatments with application of organic manure increased or decreased in rate, the content of Fe-Al oxides varied irregularly. Correlation analysis and analysis using the structural equation model (SEM) show that the content of >0.25 mm aggregates increased along with growing organic carbon fraction and with rising free iron oxide (Fed) content, but decreased with rising chelated oxide (Fes) content, and >0.25 mm aggregates were the only factor directly affecting MWD; changes in organic manure application rate induced the content of light organic carbon (LFOC) and EOC raised or declined in red paddy soils, resulted in the synergistic variation of Fed and Fes, which eventually led to changes in content of >0.25 mm aggregates. In terms of effect coefficients of the factors affecting MWD and >0.25 mm aggregates, an order of EOC > LFOC > Fed> Fes,was observed and organic carbon and its fractions were the principal affecting factors in the red paddy soil.[Conclusion] The fraction of >0.25 mm aggregates in the red paddy soil plays a key role in aggregate stability, and the fraction of active organic carbon is the major factor affecting formation and destruction of large-sized soil aggregates.
廖超林,黎丽娜,谢丽华,孙钰翔,邹炎,戴齐,尹力初.增减施有机肥对红壤性水稻土团聚体稳定性及胶结物的影响[J].土壤学报,2021,58(4):978-988. DOI:10.11766/trxb201912040540 LIAO Chaolin, LI Lina, XIE Lihua, SUN Yuxiang, ZOU Yan, DAI Qi, YIN Lichu. Effect of Increased or Decreased Application of Organic Manure on Aggregates Stability and Soil Cement in Red Paddy Soil[J]. Acta Pedologica Sinica,2021,58(4):978-988.复制