【作者】 刘鑫；

【导师】 朱端卫；

【作者基本信息】 华中农业大学 ， 植物营养学， 2001， 硕士

【摘要】 以湖北省3种酸性土壤为研究对象，以灰潮土为对照，通过盆栽试验、土壤室内培养实验研究了土壤活性锰的动态变化特征及其与油菜生物反应；并采用液流动力学方法研究了几种有机化合物对土壤锰的吸附与溶出特征。所得的主要研究结果如下： 1．在盆栽条件下，土壤酸化后pH下降，Eh上升，土壤易还原性锰转化为交换性锰和碳酸钙结合态锰，且交换性锰的增加明显滞后于碳酸钙结合态锰。由土壤Eh和pH、Mn²⁺回归模拟分析，在酸化处理中，MnO₂／Mn²⁺电对是棕红壤锰化合物变化的主要途径，MnOOH／MnO电对是黄棕壤锰变化的可能机制。 2．土壤室内培养实验中，淹水状态土壤pe+pH下降较水饱和状态更为明显，土壤易还原性锰和交换性锰呈互相消长趋势。棕红壤和黄棕壤易还原性锰含量高，土壤交换性锰增加速率大于易还原性锰含量较低的灰潮土，花岗岩发育的红壤易还原性锰最低，其交换性锰增加得最慢，这说明土壤Mn²⁺的增加与易还原性锰含量有关。抛物线扩散方程能较好地反映土壤锰的转化过程，即土壤锰的转化速率可能受扩散控制。 3．土壤对外源锰的吸附与土壤pH有关，石灰性土壤具有更强的吸附固定锰的能力。不同类型土壤锰吸附动力学以权函数方程拟合度较好。有机化合物中，柠檬酸溶出土壤锰的能力明显大于葡萄糖。在外源锰与有机化合物共存的条件下，二者产生竞争机制，即吸附与络合，哪种反应占优势，取决于土壤易还原性锰含量，棕红壤和黄棕壤主要表现为有机化合物与土壤锰的络合反应。 4．油菜锰毒害后叶片失绿黄化，叶缘卷曲皱缩，老叶上出现褐色斑点，初花期油菜开花延迟，花少，分枝较多，油菜生育期延长，经济产量下降。油菜体内吸收的锰以及Mn／Fe比与土壤交换性锰呈正相关。土壤酸化后，土壤Fe、Mn、Cu、Zn有效性增加；施用CaCO₃后，降低了油菜对Mn、Mg等元素的吸收。初花期，棕红壤与黄棕壤强酸化处理与施用CaCO₃处理，油菜对Mn、Ca和Mg的吸收都存在显著性差异，锰在油菜体内分布不均匀，为：叶＞花＞茎。更多还原

【Abstract】 The dynamic change characteristics of active manganese and the biological response of oilseed rape were studied through pot experiment and indoor incubation experiment with three acid soils under the contrast of calcareous alluvial soil in Hubei province. Meanwhile, the effect of several organic compounds to adsorption-desorption characteristics of manganese in soils was also studied by flow displacement method. Through the experiments, the main results were obtained as follows:1. In pot experiment the soil pH decreased while the Eh increased; the ERO-Mn converted to CARB-Mn; the increase of EXC-Mn was clearly hysteretic to CARB-Mn after soil acidification. Through regression analysis among soil Eh, pH and Mn2+, electrical pairs MnO2/Mn2+ was the main mode to describe the dynamic changes of Mn oxides to Mn2+ in the brown-red soil while electrical pairs MnOOH/MnO was the probable mechanism in the yellow-brown soil.2. In the incubation experiment, the soil pe + pH decreased more clearly in the flooded condition than that in the water saturation, and the EXC-Mn and ERO-Mn changed in the reverse direction. The EXC-Mn increased in this order: brown-red soil, yellow-brown soil > calcareous alluvial soil > red soil originated from granite, with the increase of soil ERO-Mn content, which indicated that the increase of soil EXC-Mn was closely related with the soil ERO-Mn concentration. Parabolic diffusion equation could better reflect the transformation process of soil Mn, This suggests that diffusion processes control the rate of Mn transformations.3. The adsorption of added Mn by soil was related to soil pH, so calcareous alluvial soil had better fit in presenting the capacity of Mn adsorption-fixation. Power function equation could better describe the adsorption dynamics of soil Mn in different soil types. Among the organic compounds, citric acid had a better capacity in dissolving soil Mn. On the basis of added Mn and organic compound coexistence, there existed two competitive mechanisms, adsorption and complex reaction, which reaction preponderated depended on the ERO-Mn content. In brown-red soil and yellow-brown soil, the complex reaction was the dominant process.4. The oilseed rape leaves turned yellow and curved from the edge; foxinessemerged in old leaves and the florescence was delayed with less flower, more twig, growth period prolonged and seed yield decreased. The Mn concentration and Mn/Fe ratio in the rape plant had a positive correlation with the soil EXC-Mn. The soil available Fe, Mn, Cu and Zn increased after acidification treatment. During the flowering stage, the Mn uptake had a significant effect on the uptake of Ca and Mg between the treatment of strong acidification and calcium carbonate application in brown-red and yellow-brown soil, and Mn in the plant distributed unevenly in this order: leave>flower>stem.更多还原