秸秆还田对褐土水稳性团聚体特征及土壤化学性质的影响

Influence of Different Modes of Straw Return on Characteristics of Cinnamon Soil Water Stable Aggregates and Soil Properties

摘要: 为探讨不同玉米秸秆不同方式还田对褐土水稳性团聚体特征及土壤理化性状的影响，于处理4年后2017年6月采集对照不施肥(CK)、施肥(C)、20%秸秆覆盖(SM20)、20%秸秆还田(SR20)、20%秸秆灰分(SA20)和20%秸秆焚烧(SC20)处理0~10 cm层的原状土壤，通过室内筛分处理后，测定土壤水稳性团聚体特征及土壤化学性质。研究表明，除C处理外，水稳性团聚体分布从大到小依次为0.5~1 mm，<0.25 mm，0.25~0.5 mm，1~2 mm，>2 mm；SR20和SC20处理平均重量直径(MWD)最高；处理C、SR20和SC20显著增加>2 mm粒级团聚体含量；SM20、SR20和SC20处理显著增加1~2 mm粒级含量；各施肥处理显著降低0.5~1 mm粒级含量；施肥处理除SC20外，均显著增加0.25~0.5 mm粒级含量；仅C处理显著增加<0.25 mm粒级含量。冗余分析发现0.5~1 mm粒级水稳性团聚体含量、土壤有机质(OM)含量、有效磷(resin-P)含量、硝态氮(NO₃^--N)含量与主轴相关，可解释总变量的57.2%；土壤有效磷含量、土壤NO₃^--N含量与< 0.25 mm粒级团聚体含量呈正向相关；土壤NH₄⁺-N含量、CaCO₃含量与1~2 mm粒级团聚体含量和MWD呈正向相关。秸秆还田和秸秆焚烧4年后土壤水稳性团聚结构最稳定，秸秆焚烧处理土壤铵态氮和有效磷含量最高，各种秸秆方式还田均能维持较高的有效磷和硝态氮含量；冗余分析结果表明，不同粒级水稳性团聚体含量分布对土壤有效养分含量及团聚体的稳定性影响不一。

Abstract: The study researched on cinnamon soil in this area under different modes of straw return. Six treatments were set up as Control, (no fertilizer, no straw); C (chemical fertilizer input); Straw mulch (SM20, 20% of straw mulch with fertilizer); SR20 (20% straw return with fertilizer); SA20 (20% straw ash with fertilizer); Straw combustion (SC20, 20% of straw combustion with fertilizer), the treatments with chemical fertilizer were applied with the same amount. After 4 years of field experiment, 0 - 10 cm soil was collected for analysis of characteristics of cinnamon soil water stable aggregates, soil chemical properties, as well as RDA relationship between them. Results showed that, all treatments beside C, the proportion of different grades of water stable aggregates were trended as 0.5 - 1 mm, <0.25 mm, 0.25 - 0.5 mm, 1 - 2 mm, >2 mm from large to small; Treatments of C, SR20 and SC20 increased >2 mm aggregates significantly; SM20, SR20 and SC20 increased 1 - 2 mm aggregates significantly; Treatments with chemical fertilization reduced 0.5 - 1 mm aggregates; Fertilization treatments all increased 0.25 - 0.5 mm aggregates except SC20; Only C treatment could increase <0.25 mm aggregate. RDA analysis showed that 0.5 - 1 mm aggregate, soil organic matter content, soil resin-P and nitrate nitrogen concentration are related to axis 1, which explained 57.2% of total variable; Soil available P and NO₃^--N concentration are positively related with <0.25 mm aggregate; Soil   and CaCO₃ contents positively related with 1 - 2 mm aggregate and mean weight diameter. Results indicated that 4 years of straw return and straw combustion had more stable aggregates than other treatments, high amount of soil NH₄⁺-N and resin-P concentration were found in SC20 treatment, while all modes of straw input to soil could maintain more resin-P and NO₃^--N than control treatment. RDA analysis showed proportion of different soil aggregate grade influenced soil available nutrients contents and stable characteristics of water stable aggregate.