镁盐添加对猪粪堆肥过程中氮、磷养分保留的影响

考察了添加氯化镁对猪粪高温堆肥过程中氮、磷养分保留的影响.结果表明,高温堆肥结束后,同对照堆体相比(氨气形态的氮素损失量为56.60g),添加镁盐的堆体(氨气形态的氮素损失量为24.25 g)减少了58%的氯气排放量;并且添加镁盐的堆体比对照堆体的总氮(TN)含量高出18%.分级磷的研究结果显示,尽管添加镁盐的堆体与对照堆体的总磷(TP)浓度接近,其中镁盐堆体TP为14.2 g/kg,对照堆体TP为12.0 g/kg,但添加镁盐有助于保留猪粪堆肥中的磷素,其中对照堆体中易溶解态磷占总磷的比例从30%提高到65%,而添加镁盐的堆体易溶解态磷的比例变化不大,保持在30%.添加镁盐的堆体中生成了含有磷酸镁的混合晶体,这可能是易溶解态磷比例减少的主要原因.

Effect of Magnesium Salt Addition on Nutrients Conservation During Swine Manure Composting

Experiments were carried out to investigate the effect of magnesium chloride addition on nutrients conservation in the thermophilic stage of swine manure composting. The results indicated that in the end of thermophilic stage of composting, the ammonia nitrogen loss of the pile with Mg-salt addition was 24.25 g, reduced by 58%, compared with 56.60 g of the control. And the total nitrogen (TN) concentration of the pile with magnesium chloride addition was higher by 18% than that of the control pile. Sequential extraction phosphorus results showed that the total phosphorus (TP) in both piles were similar (14.2 g/kg TP of the pile with Mg-salt addition and 12.0 g/kg TP of the control). However, the addition of Mg-salt is helpful for conserving phosphorus in swine compost because the percentage of the easily dissolved phosphorous forms such as H₂O-P and NaHCO₃-P in the control was increased from 30% of TP to 60% of TP, compared with that maintained at 30% of TP in the pile with Mg-salt addition. Crystal mixture which includes magnesium phosphate were found in the pile of adding magnesium chloride.