Impact of Pyrolysis Temperature on Nutrient Properties of Biochar

摘要

To understand the impact of pyrolysis temperature on the nutrient properties,biochars were produced from giant reed (Arundo donax L.) at 300-600 ℃.The nutrient properties of biochars were examined.The water-soluble Nt4+ (W-NH4+ and P (W-P) content in low temperature biochar (e.g.300 ℃) were significantly higher than that of higher temperature biochar (e.g.600 ℃),due to the loss and heterocyclizaiton of N and the formation of less soluble P crystalline minerals in high temperature biochars,respectively.The water-soluble K (W-K) content increased with increasing temperature,suggesting the increase of available K in high temperature biochars (e.g.600 ℃).With increasing pH,both the W-NH4+ and W-P release decreased in all the biochars,as well as W-K in low temperature biochars (e.g.300 ℃).However,the pH-dependent pattern for W-K disappeared in high temperature biochars (e.g.600 ℃).All these results indicated that the low temperature biochar (≤400 ℃) produced from giant reed may be a good amendment for improving the availability of nutrient in acidic soils exhibiting N,P and/or K deficiency.