施用生物炭对云南烟区红壤团聚体组成及有机碳分布的影响

生物炭是一种重要的土壤改良剂,为深入研究其对云南烟区红壤团聚体组成及有机碳分布的作用,开展了为期3年的生物炭田间定位试验.试验共设3个处理,分别为常规施肥(B0)、常规施肥配施生物炭15 t·hm-2(B15)、常规施肥配施生物炭30 t·hm-2(B30).结果表明:1随着生物炭施用年限和施用量的增加,土壤有机碳含量显著增加,B15和B30处理较对照(B0)分别增加了38.7%和60.1%;2施用生物炭显著提高了土壤各粒级团聚体有机碳含量,其中B30处理增幅最大.在不同粒级团聚体中0.25~2 mm团聚体有机碳含量增幅最大,与对照相比,B15和B30处理分别增加了24.9%和36.4%;3施炭处理(B15,B30)土壤团聚体平均重量直径(MWD)、几何平均直径(GMD)和大于0.25 mm团聚体数量(R0.25)也较对照显著增加,表明土壤团聚体稳定性显著提高;4连续施用生物炭3年后,大团聚体有机碳的贡献率明显升高,而微团聚体则相反.综上所述,生物炭对土壤团聚体和有机碳的作用过程是持续的,连续施用生物炭可显著提升土壤大团聚体含量、团聚体稳定性、土壤和各粒级团聚体的有机碳含量,在改善土壤物理性状的同时,有利于稳定增加土壤碳汇.

Effects of biochar application on soil organic carbon distribution and soil aggregate composition of red soils in Yunnan tobacco planting area

Biochar is one kind of important soil conditioner. In order to study the effect of biochar on soil organic carbon distribution and soil aggregate composition and stability of red soils in Yunnan tobacco-growing area, a biochar field experiment for a period of 3 years was performed with three treatments, including conventional fertilization (B0), conventional fertilization combined with 15 tons biochar per hectare (B15), and conventional fertilization combined with 30 tons biochar per hectare (B30). The results showed that with the increasing rate and time of biochar application, soil organic carbon increased significantly. In comparison with the control (B0), the treatments of B15 and B30 increased by 38.7% and 60.1%, respectively. The soil organic carbon of all size-fractionated soil aggregate could be obviously increased by biochar application, and B30 treatment had the largest growth rate. The soil organic carbon of aggregates larger than 0.25 mm increased the most significantly. Compared with the control, B15 and B30 treatments increased by 24.9% and 36.4%, respectively. Additionally, the mean weight diameter (MWD), geometric mean diameter (GMD) and >0.25 mm aggregate (R_>0.25) content of B15 and B30 treatments also increased significantly. The results showed that soil aggregate stabilization increased after biochar application. After persistent biochar application of 3 years, the contribution rate of organic carbon in large aggregates increased significantly, while the micro aggregates demonstrated the opposite. In summary, the effects of biochar on soil aggregates and organic carbon are continuous. The application of biochar could improve the large aggregates content, aggregate stability, organic carbon content of the soil and each aggregate class. It increased soil carbon sink while improving soil physical properties.