湖南旱地土壤对铵离子的矿物固定与固定态铵释放的动力学研究

采用振荡平衡法和好气培养-间歇淋洗法研究了湖南省主要旱地土壤对添加铵离子的矿物学固定和土壤固定态铵释放的动力学特性。结果表明,供试土壤对添加铵离子的矿物固定速度很快,反应12小时后基本上达到了最大固定量;而土壤固定态铵的释放则非常缓慢,反应42天后仍未达到最大释放量。这一动力学特征有利于土壤对溶液中NH4+的保持,防止NH4+的环境污染,有效地为作物供氮和提高氮肥利用率。一级动力学方程能较好地拟合供试土壤对铵离子的矿物学固定的动力学资料,一级动力学方程和抛物扩散率方程均能较好地拟合供试土壤固定态铵释放的动力学资料,表现为相关系数r值较高,标准误SE值较低。

Kinetics of Mineral Fixation of Added Ammonium by and Release of the Fixed Ammonium from Upland Soils in Hunan Province

The kinetics of ammonium fixation and release of fixed ammonium in the soils of Hunan Province was studied using Batch equilibrium and aerobic culture-intermittent leaching methods. The results indicated that the ammonium fixation by the soils was very fast and basically reached maximum after the reaction went on 12 hours. While the release of fixed ammonium from the soils was very slow and did not reach maximum after the release went on 42 days. First-order equation was the most adaptable to describe the NH_4~ -fixation kinetics, and both first-order equation and parabolic diffusion law equation were the most adaptable to describe the NH_4~ -release kinetics, which were characterized by the highest correlation coefficient(r) and the lowest value of the standard error of estimation (SE).