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生物炭对某些高度风化的热带土壤和温带酸性土壤有改善土壤结构,减少营养元素淋失的作用,但关于温带干旱区的盐碱土的改良效果却很少报道。以新疆绿洲盐碱土为对象,研究玉米秸秆生物炭对氮淋溶的影响。采用室内土柱淋滤试验,土柱包含炭土比(W/W)0%、1%、5%和10%四个处理,模拟大气降雨,定期收集淋滤液,分析其中的氮素指标。结果显示,5%和10%添加比例分别减少了土壤氨态氮的淋失量31.14%和52.43%,1%的添加比例增加了铵态氮淋失。对比空白,10%处理的铵态氮、硝态氮和总氮减少淋失量分别达到52.43%、50.01%和33.83%,1%和5%处理土柱的硝态氮和总氮在试验10 d内(降雨量140 mm)就基本淋失完,而10%处理土柱则显得较为平缓,几乎到25 d(降雨量290 mm)时才基本淋失完。四个土柱的铵态氮的淋失都较为平缓。另外,生物炭可以减少土柱的溶液淋失量(20.95%),增加土壤持水能力。上述结果表明,生物炭施用于干旱区盐碱土能明显减少硝态氮和总氮淋失并延长其在土壤中的停留时间,增强土壤的持续供氮能力。
Biochar can improve the soil structure and reduce the leaching of nutrient elements in some highly weathered tropical and temperate soils. However, the improvement of saline-alkali soil in temperate arid regions is seldom reported. Taking oasis in Xinjiang oasis as an example, the effects of biochar of corn stover on nitrogen leaching were studied. The soil column leaching test was used. The soil column contained four treatments of 0%, 1%, 5% and 10% of carbon to soil ratio (W / W) to simulate the rainfall in the atmosphere and collect the leachate periodically to analyze the nitrogen index. The results showed that 5% and 10% of the additive ratio decreased the leaching amount of soil ammonia nitrogen by 31.14% and 52.43% respectively, and the addition of 1% increased the leaching of ammonium nitrogen. Compared with blank, 10% treated ammonium nitrogen, nitrate nitrogen and total nitrogen reduced leaching amount reached 52.43%, 50.01% and 33.83%, respectively. Nitrate and total nitrogen in 1% and 5% (within 140 mm of rainfall), the 10% treatment soil column appears to be relatively flat and barely finished in nearly 25 days (290 mm rainfall). The leaching of ammonium nitrogen from the four soil columns is relatively flat. In addition, biochar can reduce soil column leaching loss (20.95%), increase soil water holding capacity. The above results show that the application of biochar to saline-alkali soil in arid area can significantly reduce leaching of nitrate nitrogen and total nitrogen and prolong its residence time in soil, and enhance the sustainable nitrogen supply of soil.