白浆土某些理化特性与改良的研究

为了有效地开展白浆土改良工作，自１９８６年开始，作对白浆土某些理化特性进行了调查。结果表明，白浆土关键问题在于白浆层。主要表现在两个方面：一是该层土壤水分性状不良，有效水不足，只有５．３９％，透水能力差，饱和透水系数仅为６．０８×１０＾－５ｃｍ／ｓ；二是土壤硬度过大，达２５ｋｇ／ｃｍ＾２以上。由于白浆层土壤出现部位浅，矛盾集中反映在耕层，造成耕层根系有效土层浅，表早表涝严重，直接混入耕层后，土壤

RESEARCH ON SOME PHYSICAL-CHEMICAL PROPERTIES AND IMPROVEMENT OF PLANOSOLS

To efficiently improve planosols in Sanjiang Plain in the northeastern part of China, the physical chemical properties of planosols have been investigated since 1986. The results showed that the AW layer, about 18-40cm in depth, was the key problem in planosol. In the subsoil layer, the water regime is poor with only 5.39% available water. The soil permeability is only 6.08×10^-5cm/s in saturation. Meanwhile, the soil hardness in over 25kg/cm². Because the Aw layer is so close to the surface soil that many problems occur in the ploughing layer, such as shallow available soil layer for crop roots, heavy water logging and drought. When this layer was ploughed into surface soil, the mixed soil could became harder and tighter than before. Nearly 65% of total phosphorus was observed to be organic phosphorus in Ap layer and the contents of p fractions are in the order: Fe-P > Al-P > Ca-P. During the soil incubation, 50%-60%, 10%-20% and 2%-10% of the applied p were changed into Ca-P, Al-P and Fe-P, respectively. According to above-mentioned results, emphasis of the soil improvement should be placed on the Aw layer.