生物炭施用下土壤微生物量碳氮的动态变化

Dynamics of Soil Microbial Biomass Carbon and Nitrogen After Biochar Application

为了研究生物炭施用量对整个玉米生育期内土壤微生物量及玉米产量的影响,采用田间定位试验,生物炭施用量设置0(BC0)、10(BC1)、20(BC2)和30(BC3) t·hm^(-2)共4个处理,测定不同处理下土壤微生物量碳、氮及其动态变化和收获后玉米的籽粒产量。结果表明,玉米生育期内各土层土壤微生物量碳随生物炭施用量的增加而增加;与BC0相比,施用生物炭对播种前土壤微生物量碳的影响最为显著,其中,BC3处理在0-10、10-20和20-30 cm土层的微生物量碳较对照分别增加103.2%、91.8%和158.5%。土壤微生物量氮和微生物量碳氮比的变化则与玉米生育期有关。从整个生育期来看,土壤微生物量碳、氮含量在播种前最低,在拔节期达到峰值,之后缓慢降低并保持相对稳定。在播种前,BC3处理土壤微生物商增幅最大,较BC0增加了59.5%,其他生育期土壤微生物商无显著变化。玉米籽粒产量随生物炭施用量的增加而增加,BC2和BC3分别较BC0显著增产11.2%和14.1%。因此,在土壤中施用生物炭可在一定程度上增加土壤微生物量,提高土壤肥力,增加作物产量,为该地区生物炭的合理施用提供理论依据。

A field experiment was carried out to determine the effects of biochar on the dynamics of soil microbial biomass carbon and nitrogen during maize growing season, and the yields of maize were also studied after harvest. Biochar was applied by 0(BC0), 10(BC1), 20(BC2) and 30(BC3) t·hm^(-2), and each biochar treatment reached same rates of chemical fertilizers. Results showed that soil microbial biomass carbons were generally increased with the increase of biochar application rates compared with the control in each soil layer. Compared with BC0, soil microbial biomass carbon in BC3 before planting were significantly increased 103.2%, 91.8% and 158.5% in 0-10, 10-20 and 20-30 cm soil layers, respectively. Soil microbial biomass nitrogen and the ratio of microbial biomass carbon to nitrogen were changed during the maize growing season. In addition, soil microbial biomass carbon and nitrogen were low before maize plating and reached a peak at the jointing stage, then decreased slowly and remained stable. The increase of microbial quotient in BC3 reached 59.5% before planting, while no significant effects on microbial quotient were observed at other growing stages. The yields of maize were increased with increasing biochar rate, the increases of yield in BC2 and BC3 reached 11.2% and 14.1%. In summary, the application of biochar in the soil could generally increase soil microbial biomass, improve soil fertility and crop yield. The present research provided a scientific basis for rational application of biochar in this studied area.