【摘要】 为了探明不同土壤水分条件下添加不同裂解温度和洗涤处理的生物质炭对湿地土壤氮素矿化的影响,通过720 d的室内培养法,研究了3种水分条件下(干湿交替、75%田间持水量、淹水),添加4种生物质炭(350WX:裂解温度为350℃的未洗涤生物质炭;600WX:裂解温度为600℃的未洗涤生物质炭;350X:裂解温度为350℃的洗涤生物质炭;600X:裂解温度为600℃的洗涤生物质炭)的湿地土壤矿质态氮差异特征。结果表明:与对照土壤相比,干湿交替和75%田间持水量条件下培养360 d后,添加生物质炭的土壤矿质态氮含量分别平均下降了64.62%和27.64%,氮素净矿化速率分别平均下降了82.9%和36.1%,且生物质炭对土壤氮素矿化作用的抑制率为正值;而淹水条件下,培养120 d和240 d,添加生物质炭的土壤矿质态氮含量和净矿化速率低于对照土壤,分别下降了14.93%和21.30%,且生物质炭对土壤氮素矿化作用的抑制率也为正值,但培养360 d时,高于对照土壤且平均分别增加了49.16%和176.22%,矿化作用的抑制率为负值。3种水分条件下,总体上土壤矿质态氮含量和净矿化速率均表现为添加裂解温度为350℃生物质炭的土壤大于添加裂解温度为600℃生物质炭的土壤,其中75%田间持水量条件下添加洗涤处理的生物质炭土壤大于未洗涤处理的生物质炭土壤。本研究结果表明,生物质炭施用对土壤氮素矿化抑制或促进作用受土壤水分影响,同时又深受施用时间长短、生物质炭裂解温度以及生物质炭洗涤处理的影响。更多还原

【Abstract】 Different characteristics of soil mineral nitrogen in wetland were investigated with the addition of four types of biochar(350 WX: unwashed by alcohol with pyrolytic temperature as 350℃; 600 WX: unwashed by alcoho with pyrolytic temperature as 600℃; 350 X: washed by alcohol with pyrolytic temperature as 350℃; 600 X: washed by alcohol with pyrolytic temperature as 600℃) along with 720-day room incubation under three types of water regimes(alternation of wetting and drying, 75% field water holding capacity, waterflooding) to study how water regimes control the effects of biochar addition on soil nitrogen mineralization. The results showed that, compared with CK, biochar addition decreased the mineral nitrogen content at the average degrees of 64.62% and 27.64% and the net mineralization rate at the average degrees of 82.9% and 36.1% after 360-day incubation under the alternation of wetting and drying and 75% field water holding capacity condition respectively, showing positive inhibition effects on soil nitrogen mineralization. Under waterflooding, compared with CK, biochar addition decreased the mineral nitrogen content and the net mineralization rate at average degrees of 14.93% and 21.30% after 120-day and 240-day incubation respectively, showing a positive inhibition effects on soil nitrogen mineralization, but incresed those at average degrees of 49.16% and 176.22% higher after 360-day incubation, showing negative inhibition effects on soil nitrogen mineralization. The mineral nitrogen content and net mineralization rate were always higher in soils added with biochar pyrolyed at 350℃ than those pyrolyed at 600℃ under three types of water regimes, while they were higher in soils added with biochar washed with alcohol than those in soils added with biochar unwashed by alcohol under 75% field water holding capacity condition. The study indicated that water condition controlled whether the positive or negative effects of biochar addition on soil nitrogen mineralization. Moreover, the effects were influenced by the duration of incubation, biochar pyrolytic temperature, and biochar washing treatments.更多还原