不同氮水平下秸秆、生物质炭添加对旱作农田土壤酸解有机氮组分的影响

为探明不同氮水平下秸秆、生物质炭添加对陇中黄土高原旱作农田土壤酸解有机氮组分的影响,2014年在定西市安定区李家堡镇布设的不同氮水平下秸秆、生物质炭添加定位试验(共9个处理),利用Bremner分级法,对该试验2018年收获后的土壤有机氮组分进行测定与分析。结果表明:在0～30 cm土层(0～5、5～10、10～30 cm土层),各处理酸解总有机氮、酸解氨态氮、酸解氨基酸态氮、酸解未知态氮含量均随土层的加深而降低,酸解氨基糖态氮含量随土层的加深而增加;较之无炭处理(CN0、CN50、CN100处理的均值),生物质炭添加(BN0、BN50、BN100处理的均值)处理可提升酸解总有机氮含量10.12%、9.14%、7.61%(土层由上至下),提升酸解氨态氮含量15.02%、16.25%、17.19%(土层由上至下),提升酸解氨基酸态氮含量13.31%、11.84%、8.74%(土层由上至下),其中BN100处理下对其提升效应最显著;较之无炭处理(CN0、CN50、CN100处理的均值),秸秆添加处理(SN0、SN50、SN100处理的均值)可提升酸解氨基糖态氮含量26.46%、26.51%、25.78%(土层由上至下),其中SN100处理下对其提升效应最显著;不同处理下,有机氮各形态的分布趋势为酸解氨基酸态氮酸解氨态氮酸解未知态氮酸解氨基糖态氮。总之,BN100处理对酸解氨基酸态氮、酸解氨态氮提升效应最显著,进而增加土壤供氮潜力,可筛选为该区春小麦栽培的合理施肥方式。

Effects of nitrogen fertilizer combined with straw and bio\|char on soil organic nitrogen components in dryland farmland

In order to explore the effect of straw and biochar addition on the acidolysis organic nitrogen (N) components of dry farmland soil on Longzhong Loess Plateau under different N levels, an experiment of straw and biochar addition under different N levels (9 treatments in total) was conducted in Lijiabao, Anding District, Dingxi City in 2014. Bremner classification method was used to determine the soil organic N components after harvest in 2018. The results showed that in 0~30 cm soil layer (0~5, 5~10, and 10~30 cm), the contents of total organic N, ammoniac N, amino acid N and unknown N decreased with increase in soil depth, and the contents of amino sugar N increased with the soil depth; compared with the carbon free treatment (CN0, CN 50, and CN100), biochar was added (BN0, BN50, and BN100) treatments significantly increased the content of total organic N by 10.12%, 9.14% and 7.61% (from top to bottom), 15.02%, 16.25% and 17.19% (from top to bottom) and 13.31%, 11.84% and 8.74% (from top to bottom), respectively. Compared with the carbon free treatment (CN0, CN50, and CN100), straw addition treatment (SN0,SN50, and SN100) significantly increased the content of acid hydrolyzed amino sugar N by 26.46%, 26.51%, 25.78% (from the top to the bottom of the soil layer), respectively, of which SN100 treatment had the most significant effect; under different treatments, the distribution trend of various forms of organic N was acid hydrolyzed amino acid N > acid hydrolyzed ammonia N > acidolysis unknown N > acidolysis amino sugar N. In a word, BN100 treatment had the most significant effect on the increase of acid hydrolyzed amino acid N and acid hydrolyzed ammonia N, and then increased the potential of soil N supply. It can be selected as a reasonable fertilization method for spring wheat cultivation in this area.