不同碳氮比猪粪沼渣堆肥及其产品对水稻种子萌发的影响

Research on composting of swine manure biogas residue and sawdust with different C/N and effects of the products on germination characteristics of rice seed

以猪粪沼渣为原料,木屑为辅料,进行工厂化堆肥试验。试验设置初始碳氮比(C/N)分别为13、17、21和25的4个处理(B1、B2、B3和B4),研究堆肥过程中温度、水分、有机碳和全氮含量及C/N的动态变化,比较不同处理堆肥产品性质差异及对水稻种子萌发及生长的影响。结果表明,B1处理最晚进入高温期,B4处理最早开始降温,4个处理的高温期分别持续24、36、27和24 d。堆肥过程中,B1和B2处理含水量总体较高。不同处理有机碳含量和C/N总体呈下降趋势,全氮含量则在堆肥前期总体上升而在中后期有一定程度下降。堆肥产品的有机质含量、EC值和铵态氮含量随着初始C/N的增大呈增加趋势,而氮、磷、钾含量及pH则随C/N增大而降低。除B1处理外,其余处理堆肥产品在有机质和总养分含量及酸碱度上均符合国家标准。堆肥产品的水稻种子萌发试验结果显示,B3处理种子活力指数、幼苗芽长、芽鲜重、总鲜重、芽干重和总干重最高,较去离子水对照分别高77.3%、70.7%、125.1%、44.9%、115.3%和15.3%。综合考虑堆肥过程、堆肥产品品质及产品的促生效果,以猪粪沼渣和木屑进行堆肥生产有机肥,初始C/N设定为21最为适宜。

A plant-scale composting experiment was set up,in which swine manure biogas residue and sawdust were used as raw and supplementary materials and mixed to primary C/N of 13,17,21 and 25(B1,B2,B3 and B4).As to the four treatments,changes of temperature,moisture,organic carbon and total nitrogen contents,and the ratio of carbon to nitrogen(C/N)during composting were monitored,differences in properties of compost products were compared,and effects of compost products on seed germination and seedling growth of rice were studied.The result showed that treatment B1 was the last to enter thermophilic phase,while B4 was the first to enter cooling phase.The duration of thermophilic phase of the four treatments were 24,36,27 and 24 d,respectively.The water contents of treatments B1and B2 were relatively high during the whole composting.Organic carbon contents and C/N of all treatments showed trend of decreasing,while total nitrogen contents increased in the early stage and decreased to some extent in the middle and late stage of composting.Organic matter content,EC and ammonium nitrogen content of the composing products increased with increasing C/N,but it appeared the opposite change for contents of nitrogen,phosphorus and potassium and pH.The composing products of all the treatments except for B1 met the national standard in contents of organic matter and total nutrients and pH.A germination test of rice seed was conducted using the composing products.The result showed that seed vigor index,shoot length,shoot fresh weight,total fresh weight,shoot dry weight and total dry weight of B3 were all the highest among all the treatments,which were 77.3%,70.7%,125.1%,44.9%,115.3%and 15.3%higher than those of deionized water control.Based on comprehensive consideration of composting process,and quality and growth promoting effect of composting products,the initial C/N value of 21 was suitable for composting with swine manure biogas residue and sawdust in production of organic fertilizer.