生物质灰渣中的磷、钾释放动力学特征研究

A Study on the Dynamic Characteristics of Phosphorus and Potassium Release in Bio-Ashes

采用连续液流法研究了4种生物质灰渣（水稻秸秆灰渣、玉米秸秆灰渣、谷壳灰渣、锯木灰渣）中磷、钾的释放动力学特征.结果表明：（1）4种生物质灰渣磷的释放均在40min左右达到平衡,而水稻秸秆灰渣中钾的释放在100min左右达到释放平衡,其他3种秸秆灰渣在10min左右达到释放平衡,释放平衡与灰渣种类及其磷、钾含量有关.（2）平衡前不同时间段4种灰渣磷的释放反应速度与反应时间的自然对数（lnt）间存在良好的线性关系,其相关系数在0.966~0.997之间,达到极显著水平;4种灰渣钾的释放反应速度与反应时间的自然对数（lnt）间也存在良好的线性关系,其相关系数在0.749~0.980之间,达到显著水平,其反应速度直线的斜率、截距及初始反应速度与不同种类的灰渣磷、钾含量有关.（3）水稻秸秆灰渣及锯木灰渣磷的总释放量达到3.5cmol/kg及5.1cmol/kg,钾的总释放量达到41.93cmol/kg及6.92cmol/kg,是较优的生物质肥料.（4）4种不同生物质灰渣钾的释放量及释放速率均大于磷.生物质灰渣有利于土壤中速效磷、钾含量的提高,按实际需要选择并合理配比,能达到较好的土壤改良效果.

The continuous flow method was used to study the dynamics of phosphorus and potassium release from four different kinds of bio-ash,i.e.rice bio-ash,corn bio-ash,chaff bio-ash and sawmilling bioash.Phosphorus release from the 4different experimental bio-ashes all reached balance in about 40minutes,while potassium release reached balance in around 100minutes from the rice bio-ash and in about 10 minutes from the other three kinds of bio-ash,indicating that the balance is related to the species and content of phosphorus and potassium.The liberation velocity of different periods before the equilibrium was in a highly significant linear relationship with the natural logarithm of time（lnt）,the correlation coefficient of phosphorus being between 0.966＊＊and 0.997＊＊,and the correlation coefficient of potassium being between 0.749＊and 0.980＊.The speed linear slope,intercept and the initial reaction rate were related to the phosphorus and potassium contents in different kinds of ash.The total release quantity of phosphorus and potassium in the rice bio-ash and the sawmilling bio-ash were 3.5cmol/kg and 41.93cmol/kg,and 5.1cmol/kg and 6.92cmol/kg,respectively,indicating that they were fairly good biological fertilizers. The release quantity and release rate of potassium in different bio-ashes were greater than those of phosphorus.In conclusion,bio-ash application is beneficial to the improvement of available phosphorus and potassium content in soil,and rational proportion of application based on practical needs can achieve the effect of soil improvement.