脱硫石膏淋洗次数对铵态氮迁移特征的影响

Effects of the Leaching Times and Flue Gas Desulfurization Gypsum on Ammonium Nitrogen Transport in Solonetz

基于室内土柱穿透试验,设置4组试验处理:3组施加脱硫石膏,不同次数淋洗处理;1组无脱硫石膏无淋洗对照处理。通过分析NH+4、Ca2+、Na+3种离子相互关系及土壤水力传导度的变化情况,研究脱硫石膏及不同淋洗次数对碱土养分离子铵态氮迁移转化的影响。结果表明:碱土混合脱硫石膏后未经淋洗的情况下会抑制碱土对NH+4的吸附效果,但随着穿透前被淋洗次数的增加,NH+4在盐碱土中穿透曲线的斜率减小,吸附作用增强。从节水控盐、促进土壤肥力吸收、抑制土壤次生盐碱化的因素来看,根据试验结果推测铵肥不适合与脱硫石膏同时施加到碱土土壤中。建议在施肥前,拌施脱硫石膏的碱土宜采用秋浇与春灌相结合的方式,每次淋洗662.7 m3/hm2水量,这种淋洗方式在保证改良效果,促进肥料吸收的基础上,还可以适当减少秋浇灌水量,合理分配灌区有限的淡水资源。

Based on the soil column breakthrough experiment in laboratory, four treatments （desulfurization gypsum with none or one or three leaching times; no desulfurization gypsun with none leaching time） were set up. With the analysis of relationship among these three ions： NH4^＋, Ca^2＋, Na^＋ and the hydraulic conductivity （HC）, the effects of the leaching times and flue gas desulfurization gypsum on ammonium nitrogen transport in solonetz were investigated. The results showed that the suppression of the adsorption of ammonium was occurred in the solonetz combined with desulfurization gypsum without leaching. But with the leaching times increasing before penetration, the slope of the breakthrough curve reduced and the adsorption enhanced. In the view of controlling water and salt, promoting the adsorption of fertilizer, inhibition of soil secondary salinization, it was inappropriate to put the ammonium fertilizer together with desulfurization gypsum in solonetz at the same time. It suggested that the solonetz mixed with desulfurization gypsum should be leached two times, which are autumn irrigation and spring irrigation, with the leaching amount of 662.7m^3/hm^2. On the basis of ensuring the reclamation effect, this leaching way can decrease the amount of autumn irrigation and distribute the limited freshwater resources reasonably in the area.