通过安排田间试验,在旱作农田土壤中施用果树树干、枝条生物炭,分层分析不同用量(0、20、40、60、80 t·hm-2)生物炭对农田土壤有机碳、氮及其组分的影响。结果表明:在0~10 cm土层,土壤总有机碳(TOC)、颗粒有机碳(POC)、易氧化有机碳(EOC)随生物炭施用量的增加而增加,微生物生物量碳(MBC)、全氮(TN)、碱解氮(AN)、硝态氮(NO-3-N)、微生物生物量氮(MBN)均在生物炭施用量为60 t·hm-2时达到最大,分别比对照(B0)显著增加87.22%、33.33%、18.76%、94.79%、178.80%;在10~20 cm土层,TOC、POC、TN、NO-3-N随生物炭施用量的增加而增加,EOC、MBC、AN均在生物炭用量为60 t·hm-2时达到最大,分别比B0显著增加78.05%、23.85%、31.07%,而MBN在40 t·hm-2时达到最大,比B0显著增加50.87%;在20~30 cm土层,并没有直接地施用生物炭,但因为上层生物炭的影响,除NO-3-N外,其余各指标含量多在60 t·hm-2或80 t·hm-2时显著高于B0;此外,随生物炭施用量的增加,土壤有机碳储量和氮储量在0~30 cm土层分别增加37.92%~108.31%和1.05%~14.94%,其中氮储量在生物炭用量为60 t·hm-2时达到最大。相关分析也表明,土壤TOC、EOC、POC、TN、AN、NO-3-N含量与生物炭施用量呈极显著的正相关(P<0.01)。因此,适量施用生物炭具有提高旱作农田土壤有机碳、氮含量,增加土壤碳截留,提升土壤养分供应的能力。推荐生物炭施用量为60 t·hm-2。
In recent years, biochar has become an emerging soil amendment, and has multiple agricultural and environmental benefits. Here,a long-term field trial was carried out to investigate the effects of different rates of biochar(0, 20, 40, 60 t·hm-2, and 80 t·hm-2)on soil organic carbon and soil total nitrogen and their fractions. The biochar used in this study was produced from fruit tree branches at pyrolysis temperature of approximately 450 ℃. In 0~10 cm soil layer, total organic carbon(TOC), particulate organic carbon(POC) and easily oxidized organic carbon(EOC) increased with increasing rates of biochar. At 60 t·hm-2biochar, microbial biomass carbon(MBC), total nitrogen(TN), alkaline hydrolysis nitrogen(AN), NO-3-N, and microbial biomass nitrogen(MBN) were the greatest, which were significantly increased by 87.22%, 33.33%, 18.76%, 94.79%, and 178.80%, respectively, compared to the control(B0). In 10~20 cm soil layer, TOC,POC, TN and NO-3-N increased as biochar rates increased. EOC, MBC, and AN were the highest at 60 t·hm-2biochar, which were significantly increased by 78.05%, 23.85%, and 31.07%, respectively, over the control. Applying biochar at 40 t·hm-2led to the highest MBN, a50.87% higher than the control. In 20~30 cm soil layer, no biochar was directly applied to this layer, but all measurements except NO-3-N were significantly higher at 60 t·hm-2or 80 t·hm-2biochar than those of the control(B0). Applying biochar increased soil organic carbon reserves and nitrogen reserves in 0~30 cm soil layer by 37.92%~108.31% and 1.05%~14.94%, respectively. Soil nitrogen reserves reached the maximum at biochar rate of 60 t·hm-2. Total organic carbon, EOC, POC, TN, AN, and NO-3-N were significantly positively correlated with biochar rates(P<0.01). The results show that biochar at 60 t·hm-2yields the greatest effects in increasing soil organic carbon and nitrogen contents and improving nutrient supply in the rainfed farmland.
Journal of Agro-Environment Science( J. Agro-Environ. Sci.)