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为探究林农复合对土壤团聚体、土壤有机碳、土壤微生物生物量碳的影响,在辽西地区选取樟子松-花生、樟子松-谷子、樟子松纯林(对照)为研究对象,对其土壤团聚体、团聚体有机碳、土壤微生物生物量碳以及土壤有机碳含量及其分布特征进行研究。结果表明:(1)研究区土壤团聚体以0.053~0.25 mm粒级为主,占团聚体总量的37%~45%,其中樟子松-谷子的大团聚体(>0.25 mm粒级)含量最高。(2)两种林农复合各粒级团聚体有机碳含量变化显著不同(P<0.05),樟子松-花生团聚体有机碳随粒径增大呈现“倒N”型分布,而樟子松-谷子土壤团聚体有机碳随粒径增大呈现“N”型分布。(3)0~20 cm表层土壤微生物生物量碳和有机碳含量大小顺序为:樟子松-谷子>樟子松纯林>樟子松-花生。(4)试验区土壤有机碳的积累主要受0.053~0.25 mm和>2 mm粒级团聚体含量的影响;另外,0~50 cm土壤剖面微生物生物量碳和有机碳相关分析表明,樟子松-谷子土壤微生物生物量碳与有机碳具显著相关性,而在樟子松-花生复合林地内无显著相关性;这说明不同营林措施对土壤有机碳和微生物的影响存在差异。综上,辽西地区樟子松-谷子复合措施有利于改善土壤结构,促进大团聚体的形成,对提高土壤保水、供肥能力,实现对土壤的保护和可持续利用具有较为明显的作用。
In order to explore the impact of forestation and agro-composite on soil aggregate, soil organic carbon and soil microbial biomass carbon, we selected Pinus sylvestris-peanut, Pinus sylvestris-Mongolica and Pinus sylvestris var.mongolica as control, Soil aggregates, aggregates organic carbon, soil microbial biomass carbon and soil organic carbon content and their distribution characteristics were studied. The results showed that: (1) Soil aggregates in the study area were dominated by 0.053-0.25 mm grain size, accounting for 37% -45% of the total aggregates. Among them, large aggregates of Pinus sylvestris-millet (> 0.25 mm grain size) The highest content. (2) There were significant differences in organic carbon content between the two kinds of aggregates (P <0.05). The SOC of the Pinus sylvestris-peanut aggregates showed “inverted N” The organic carbon of soil aggregates showed a “N ” type distribution with increasing particle size. (3) The sequence of soil microbial biomass carbon and organic carbon in 0 ~ 20 cm soil layer was: Pinus sylvestris-Millet> Pinus sylvestris var.mongolica> Pinus sylvestris-peanut. (4) The accumulation of soil organic carbon in the experimental area was mainly affected by the content of aggregate fractions of 0.053-0.25 mm and> 2 mm. In addition, the correlation analysis of soil microbial biomass carbon and organic carbon in 0-50 cm soil profile showed that Pinus sylvestris There was a significant correlation between soil microbial biomass carbon and organic carbon in millet soil, but no significant correlation in Pinus sylvestris var. Mongolica-peanut mixed forest. This indicated that there were differences in the effects of different silvicultural practices on soil organic carbon and microorganisms. In summary, the Pinus sylvestris-millet compounding measures in western Liaoning are conducive to improving soil structure and promoting the formation of large aggregates, which play a significant role in improving soil water conservation and fertilizer supply and realizing the protection and sustainable use of soil.