耕作改制对砂姜黑土中锰的影响

研究砂姜黑土旱改水对土壤中Mn含量、赋存形态和有效性的影响结果表明,砂姜黑土中Mn存在于粘土矿物、晶形氧化铁、无定性氧化铁、氧化锰态、有机物和碳酸盐中比例分别为27.19%~46.26%、10.48%~21.65%、2.76%~12.28%、17.39%~26.53%、10.61%~24.57%和0.16%~8.35%。旱改水实施水旱轮作后砂姜黑土中全Mn含量极显著降低,平均降幅为8.77%,但伴随土壤pH值的趋中性,土壤中Mn由植物有效性较低的晶形铁结合态逐渐向植物有效性较高的氧化锰态、无定形铁态和有机态转化,活化了土壤中的Mn,提高了Mn的有效性和可移动性。

Effect of cropping system on the manganese in lime concretion fluvo-aquaic soils

The influences of cropping system changing from upland farming to the rotation of rice and upland farming on the total content, morphology and availability of manganese in lime concretion fluvo-aquic soils were studied. The results show that the contents of manganese in the residual, crystalline iron oxide bound, amorphous iron oxide bound, manganese oxide, organically bound and carbonate bound account for 27.19% -46.26%, 10.48% -21.65%, 2.76%-12.28%, 17.39%-26.53%, 10.61%-24.57% and 0.16%-8.35%of the total manganese content in soils, respectively. With the change of cropping system from upland farming to the rotation of rice and upland farming, manganese is released from crystalline iron oxide, and further transferred into organic matter and amorphous iron oxide or exists solely as manganese oxide. These result in the increase of the movability and availability of manganese for crops, leading to the decrease of the total content of manganese and the decreasing range that is 8.77 % in the tilled layer of soils for rotation of rice and upland crops.