Fundamental Study for the Development of Soil Conditioning Agent from Lignin

由于土壤酸性，植物生长受到极大的抑制，这对受灾地区的造林是一个严重的问题，特别是在东南亚。这主要是由于酸性条件下土壤水中铝离子浓度较高所致。在森林土壤中，表层土壤中的腐殖质可能具有控制溶解铝浓度的作用。本研究尝试了以工业木质素(硫酸盐木质素)为原料，通过碱氧氧化和自由基磺化处理制备新型土壤改良剂。结果表明，添加改性木质素可以完全消除铝离子对萝卜根生长的抑制作用。用120ppm碱氧处理的半木质素可以消除5ppm铝离子的影响，而5ppm的铝离子对萝卜根尖的生长几乎是抑制的。就改性木质素的作用机理而言，值得注意的是，添加改性木质素抑制了铝离子在根尖上的吸附。

It is a serious problem for the reforestation of damaged area especially in the South East Asia that plant growth is extremely inhibited because of acidic soil. This is basically due to the high concentration of aluminium ions dissolved into the soil water from soil because of acidic condition . In the sound soil in the forest, humic substances in the surface soil may have a function to control the concentration of dissolved aluminium. In this research, new soil conditioning agents were tried to prepare from industrial lignin (kraft lignin) by alkaline-oxygen oxidation and radical sulfonation treatments.It was clearly confirmed that growth inhibition of radish root because of aluminium ions was completely removed by the addition of a modified lignin to the culture medium. Effect of aluminium ions of 5ppm, in which the growth of radish root is practically prohibited at pH4.5, was removed by 120ppm of alkaline-oxygen treated haft lignin.As far as the function mechanism of a modified lignin, it was interesting to note that adsorption of aluminium ions to the tip of root was inhibited by the addition of a modified lignin.