不同原料生物炭对酸性红壤氮素转化及理化性质的影响

Effects of biochar from different feedstocks on soil nitrogen transformation and physicochemical properties in acid red soil

为探究施用不同原料生物炭对酸性土壤改良及氮素矿化作用和硝化作用的影响,以酸性红壤为供试土壤,添加水稻秸秆、稻壳及木屑3种原料制备的生物炭,开展为期50 d的室内培养试验。设置空白对照(CK)、单施化学肥料(F)、水稻秸秆生物炭+化学肥料(B_(1))、稻壳生物炭+化学肥料(B_(2))、木屑生物炭+化学肥料(B_(3))共5个处理,测定土壤基础理化性质、酶活性及铵态氮与硝态氮含量,分析土壤性质与氮素转化之间的关系。结果表明:水稻秸秆生物炭对土壤pH提高效果高于木屑生物炭和稻壳生物炭,与CK和F处理相比,B_(1)处理使土壤pH提高了0.10和0.64个单位,且B_(1)处理土壤有机质、总氮、速效磷及速效钾含量也均显著高于其他处理。施用肥料(F)和生物炭(B_(1)、B_(2)、B_(3))显著提高了土壤氮素矿化速率和硝化速率,且不同原料生物炭处理之间存在显著差异。培养50 d后,B_(1)、B_(2)、B_(3)处理平均氮素矿化速率相对于F处理分别降低了81.5%、87.6%和28.1%。与F处理相比,B_(1)、B_(3)处理能固持土壤硝态氮,并分别使硝化速率提高了12.0%和16.0%,而B_(2)处理使硝化速率降低了18.5%。此外,不同生物炭处理的土壤碳氮转化相关酶活性也存在显著差异。不同原料生物炭对酸性红壤理化性质的影响不同,土壤性质的差异可对氮素转化产生影响,合理施用生物炭可固持土壤氮素,减少氮素损失。

To investigate the effects of biochar from different feedstocks on acid soil improvement,nitrogen(N)mineralization and nitrification,acid red soil was selected as experiment material,and different biochar prepared from rice straw,rice husk and wood were added to carry out a 50‐day indoor culture experiment.Five treatments had been set:CK(control),F(chemical fertilizer),B_(1)(rice straw biochar with chemical fertilizer),B_(2)(rice husk biochar with chemical fertilizer),B_(3)(wood biochar with chemical fertilizer).The soil basic physicchemical properties,enzyme activity and the contents of ammonium N and nitrate N were determined to analyze the relationship between soil properties and N transformation.The results showed that rice straw biochar improved soil pH better than wood biochar and rice husk biochar.Compared with CK and F treatment,the soil pH in B_(1) treatment increased by 0.10 and 0.64 units,respectively.Besides,the contents of soil organic matter,total N,available phosphorus and available potassium in B_(1) treatment were also significantly higher than that of other treatments.Furthermore,the application of fertilizer(F)and biochar(B_(1),B_(2),B_(3))significantly increased the soil N mineralization rate and nitrification rate,and there were significant differences in different biochar treatments.Throughout the 50‐day experiment,compared to F treatment,the average N mineralization rates in B_(1),B_(2) and B_(3) treatments decreased by 81.5%,87.6%and 28.1%,respectively.Meanwhile,treatment B_(1) and B_(3) could hold soil nitrate N and increase the nitrification rate by 12.0%and 16.0%,respectively,while B_(2) treatment reduced the nitrification rate by 18.5%.In addition,the soil carbon and N cyclerelated enzymes activity in different biochar treatments were significantly different.Totally,the results indicated that biochar from different feedstocks have different effects on the physicchemical properties of acid red soil,and the differences of soil properties could affect the N transformation,and rational application of biochar can hold soil N and reduce N loss.