两种不同镁盐在牛粪堆肥高温期的保氮效果研究

利用恒温培养箱模拟堆肥高温期,添加硫酸镁、磷酸二氢钾和含镁废渣,研究磷酸铵镁(MAP)反应中各成分的保氮效果以及含镁废渣作为堆肥过程中氮素固定剂的可行性。结果表明:添加镁盐固定剂显著降低了堆体中的pH值,减少了氮素损失。同时添加硫酸镁和磷酸二氢钾的保氮效果最佳,添加相同比例的含镁废渣和硫酸镁的保氮效果无显著差别。含镁废渣添加量的保氮效果与其添加量成正相关,添加质量比为2%、4%、8%的含镁废渣的保氮率分别为6.15%、10.13%、19.51%。添加镁盐会提高堆体中的EC值,降低GI值,各处理均可达到腐熟。说明可以利用镁盐作为堆肥保氮固定剂,而含镁废渣因其价格低廉,更具应用前景。

Effect of Two Different Magnesium Salt on Nitrogen Fixing in High-temperature Phase of Cattle Manure Composting

The authors applied the constant temperature incubator to simulate the composting high temperature stage with MgSO4, KH2PO4 and magnesium slag addition. The nitrogen protect effect of each component in magnesium ammonium phosphate (MAP) and magnesium slag as the feasibility of nitrogen fixing agent in composting process was studied. The results showed that magnesium fixing agent addition significantly reduced the pile pH value and decreased nitrogen loss. Addition of MgSO4 and KH2PO4 at the same time could bring the best nitrogen protect effect. There was no significant difference between MgSO4 and magnesium slag addition with the same rate. Nitrogen protection efficiency was positively related with magnesium slag addition amount, the nitrogen protection efficiency of magnesium slag addition amount 2%, 4% and 8% was 6.15%, 10.13% and 19.51%, respectively. Magnesium materials addition could increase EC value and reduce the GI value. All the trials could achieve maturity, indicating that magnesium materials could be used as nitrogen fixing agent in composting and magnesium slag had application prospects because of low price.