化肥与不同有机物料配施对土壤有机碳组分及土壤水稳性团聚体的影响

The Effects of Combined Application of Chemical Fertilizers with Different Organic Materials on Soil Organic Carbon Components and Soil Water-stable Aggregates

【目的】通过探究化肥与不同有机物料配施对土壤水稳性团聚体和有机碳组分的影响,为增加土壤碳固存,改善土壤结构,指导有机物料合理利用提供科学依据。【方法】进行化肥与有机物料配施试验,以玉米为供试作物,设置5个处理,分别为单施化肥(CK)、化肥+羊粪(AF)、化肥+木薯渣(PF)、化肥+木本泥炭(MF)、化肥+味精废浆料(IF),测定不同处理下土壤有机碳组分和水稳性团聚体含量。【结果】与CK相比,各施用不同有机物料处理的土壤总有机碳(TOC)含量提高了7.93%~24.67%,可溶性有机碳(DOC)、易氧化有机碳(ROC)、微生物生物量碳(MBC)含量均有增加;其中,IF处理的TOC、ROC含量最高,MBC含量最低;AF处理的DOC含量最高;MF处理的MBC含量最高,而TOC、DOC、ROC含量均最低。不同有机物料处理的活性碳组分在总有机碳中的分配比率均有差异,相比CK,仅有AF处理的DOC/TOC有所增加,而各施用有机物料处理的ROC/TOC和MBC/TOC均有增加。施用有机物料明显增加了1~2 mm和0.5~1 mm粒级的土壤水稳性团聚体含量,有利于>0.25 mm粒径大团聚体的形成,且各处理的土壤水稳性团聚体在2~5 mm粒级内占比最高。施用有机物料后,土壤水稳性大团聚体含量提高了17.64%~30.48%,土壤水稳性团聚体的平均重量直径(MWD)表现为AF>PF>IF>MF>CK的变化趋势。相关性分析表明,DOC与土壤水稳性团聚体大团聚体含量(MR>0.25)、MWD和GMD之间呈显著正相关,说明DOC含量越高,土壤团聚体稳定性越强。【结论】施用味精废浆料对土壤有机碳的提升效果最好,施用羊粪后土壤水稳性团聚体稳定性最好。

Objective This study was to provide a scientific basis for rantional utilization of organic materials and improving soil structure by investigating the effects of combined application of chemical fertilizers with different organic materials on soil water-stable aggregates and organic carbon sequestration.Method A field experiment was conducted with maize as the tested crop,including five treatments:sole chemical fertilizer(CK),chemical fertilizer with sheep manure(AF),chemical fertilizer with cassava residues(PF),chemical fertilizer with woody peat(MF),and chemical fertilizer with monosodium glutamate waste pulp(IF).The soil organic carbon fractions and water-stable aggregate contents were measured under different treatments.Result Compared to CK,the soil total organic carbon(TOC)content in soils treated with various organic materials increased by 7.93%to 24.67%,and the contents of dissolved organic carbon(DOC),readily oxidized organic carbon(ROC),and microbial biomass carbon(MBC)increased as well.Among them,the IF treatment had the highest TOC and ROC contents but the lowest MBC content,while the AF treatment had the highest DOC content.The MF treatment had the highest MBC content but the lowest TOC,DOC,and ROC contents.The allocation ratios of active carbon fractions in total organic carbon differed among the organic material treatments.Only the AF treatment showed an increase in DOC/TOC compared to CK,but all organic material treatments led to an increase in ROC/TOC and MBC/TOC.Application of organic materials significantly increased the contents of soil water-stable aggregates in the 1-2 mm and 0.5-1 mm size fractions,promoting the formation of larger aggregates(>0.25 mm)as well.The proportion of soil water-stable aggregates within the 2-5 mm size fraction was highest across treatments.After applying organic materials,the content of large water-stable aggregates increased by 17.64%to 30.48%,and the mean weight diameter(MWD)of the water-stable aggregates followed the trend of AF>PF>IF>MF>CK.The correlation analysis revealed a significant positive relationship between DOC and the content of soil water-stable aggregates in the macro-aggregate fraction(>0.25 mm),as well as the mean weight diameter(MWD)and geometric mean diameter(GMD)of aggregates.This finding suggested that higher level of DOC contributed to enhance stability of soil aggregates.Conclusion Overall,the application of MSG waste pulp exhibited the greatest effectiveness in enhancing soil organic carbon content,while the application of sheep manure resulted in the highest stability of soil water-stable aggregates.