【摘要】 通过野外调查取样、室内培养试验和分析测定,研究了湖南省几种成土母质发育的旱地土壤和稻田土壤固定添加铵的动力学特性。结果表明,供试土壤对添加铵的固定速度很快,尤其在反应的前8~12 h内速度更快,12 h后速度逐渐变慢,24 h以后,土壤对外源铵的固定已基本达到平衡。数学拟合表明,一级动力学方程和Elovich方程两种动力学模型能较好地拟合供试土壤固定添加铵的动力学特性,经统计均达极显著水平,抛物扩散方程也有较好的拟合效果,零级方程较差。由一级动力学方程求得的不同土壤固铵动力学参数:理论最大固铵量(A)、反应速率常数(b)以及反应半时值明显不同。耕型石灰性紫色土、耕型酸性紫色土、耕型棕色石灰土和耕型石灰岩红壤的理论最大固铵量和反应半时值分别为212.3 mg kg-1、179.0 mg kg-1、142.9 mg kg-1、13.7 mg kg-1和29.75 h、25.96 h、27.18 h、23.49 h;紫泥田、河沙泥、灰泥田和红黄泥的理论最大固铵量和反应半时值分别为86.2mg kg-1、68.7 mg kg-1、31.8 mg kg-1、19.1 mg kg-1和14.50h、15.10 h、15.51 h、18.43 h。耕型石灰性紫色土、耕型酸性紫色土、耕型棕色石灰土和耕型石灰岩红壤的反应速率常数分别为0.0233 h-1、0.0267 h-1、0.0255 h-1、0.0295 h-1;紫泥田、河沙泥、灰泥田和红黄泥的反应速率常数分别为0.0478 h-1、0.0459 h-1、0.0447 h-1、0.0376 h-1。除耕型石灰岩红壤以外,旱地土壤的理论最大固铵量和反应半时值均明显大于水田土壤,而反应速率常数明显小于水田土壤。更多还原

【Abstract】 Kinetics of ammonium fixation in several types of cultivated upland soils and paddy soils derived from representative parent materials in Hunan province,China, was studied through sampling in fields,and incubation and determination in laboratory.Results showed that fixation of added NH+4 in the tested soils, whether paddy or upland,all increased with fixation time,and the fixing rate for added NH+4 was high at the initial stage,especially at the initial 8～12 hours of reaction,and gradually slowed down afterward.After 24 hours,the fixation of added NH+4 reached equilibrium basically.Both the first order equation and Elovich equation were the most applicable to describing NH+4-fixation kinetics in the tested soils.The parabolic diffusion equation had some good fitting results,too.But the zero-level equation was not applicable.The kinetic parameters obtained through the first-order equation,i.e.,theoretical maximum fixation capacity(A),reaction rate constant(b) and half reaction time,varied with soil types.The paddy soils were lower in theoretical maximum fixation capacity(A) and half reaction time,but much higher in reaction rate constant(b) than the upland soils.更多还原