三江平原白浆土有机——无机复合胶体的研究

通过对三江平原各类型白浆土有机——无机复合胶体研究的结果看出,从岗地白浆土→平地白浆土→低地白浆土,土壤表层有机质总量依次为3.84%、4.67%、7.31%;土壤复合有机质量为3.44%、3.46%、5.11%;土壤复合度的变化梯度为89.58%、74.09%、69.90%.上述三项指标在白浆层中均很低. 表层有机——无机复合状况良好,致使土壤结构、保水、保肥性能显著优于白浆层. 因此,白浆土改良是趋利避害,发挥黑土表层优势,千方百计增厚黑土层,改造白浆层不良本性,打破白浆土黑土层薄、白浆层厚的不合理土体构造.

A STUDY ON THE PLANOSOL ORGANO-MINERAL COMPLEXES IN THE SANJIANG PLAIN

The present paper deals with the planosol organo-mineral complexes and their properties in the Sanjiang plain. The results obtained were summarized as follows. With the different periods of cultivation and the regular variation of the local ecological conditions. (1)From the terrace planosols down to alluvial plain planosols and low alluvial plain planosols, the total contents of organic matter in surface soils were 3.34%, 4.67%, 7.31%, respectively. (2) The amount of complexed organic matter were 3.44%, 3.46%, 5.11%, respctively.(3) Complexing degrees of A_1 layer of the planosols were 89.58%, 74.09%,69.90%, respectively, which proved that more than half of organic matter in the surface layer of the planosols were associated with mineral colloid, forming organo-mineral complexes. Undoubtedly, they would play an important part to the planosol fertility. The gradient of the total organic matter in the A_w layers dropped rapidly to 1.34%, 1.64%, and 2.75%, the quantity and degree of complexing organic matter were very low. Because of better complexing condition in the A_1 layers, the planosol structure and water-nutrient holding capacity there were significantly better. Therefore, the key point of planosol improvement is to increase the total contents of organic matter of A_w layers, promote the formation of organomineral complexes, improve the unfavorable properties of the A_w layers, rearrange the undesirable soil layers and increase the depth of A, layer.