氮锌配施对石灰性土壤锌形态及肥效的影响

通过分析石灰性土壤上施用锌肥后土壤中锌的形态变化,研究锌肥的有效性及后效,为指导合理施用锌肥提供理论依据。结果表明在潜在性缺锌的石灰性土壤施锌肥没有明显的增产效果,可增加小麦籽粒锌含量,但不同基因型反应差异很大;土壤中的锌主要以矿物态存在,占全锌91.5%~97.6%,其次为松结有机态锌(1.34%~5.53%)、碳酸盐结合态锌(0.47%~1.55%);施入土壤中的锌增加了交换态、松结有机态、碳酸盐结合态、氧化锰结合态锌含量,但大部分转化为矿物态;种植小麦可以使土壤中的锌向有效态转化;施氮增加了小麦对锌的吸收,也增加了锌矿化的比例;主成分分析结果表明,交换态、松结有机态和碳酸盐结合态均能不同程度反映土壤锌的有效性,石灰性土壤中碳酸盐结合态和有机结合态锌含量占有较为可观的比例,因此增加这两种形态储备容量是调节和控制土壤锌营养状况的重要措施。

Effects of combined application of nitrogen and zinc on zinc fractions and fertilizer efficiency in calcareous soil

The change of zinc fractions in soil was determined in this experiment after application of zinc fertilizer in calcareous soil. The object of this experiment was to investigate the effect and aftereffect of zinc fertilizer. The results showed that wheat yeild was not signiciantly increased. While, wheat grain Zn concentration was increased after the application of Zn in the potential zinc-deficiency calcareous soil, but there were significant differences in various genotypes. In soil zinc fractions, mineral bonded zinc accounts for 91.5%-97.6% of total zinc, organic matter loosely bonded zinc accounts for 1.34%-5.53% of total zinc and carbonate bonded zinc accounts for 0.47%-1.55% of total zinc. Zinc fractions studied in the experiments were all increased in zinc fertilizer treatment compared with the control and most of zinc added to soils has entered into soil minerals. More zinc fractions transform to the effective parts after wheat planted in this soil. Application of nitrogen fertilizer accumulates the zinc uptake of wheat. Meanwhile, the zinc mineralization rate was also increased. The analysis of principal component showed that the exchangeable zinc, the organic matter loosely bonded zinc, the carbonate bonded zinc and the manganese oxides bounded zinc could indicate the availability zinc in soils in various degrees, respectively. Carbonate bounded zinc and organic matter loosely bonded zinc account most parts of total zinc in calcareous soil. To stimulate and control the zinc nutrient condition in calcareous soil, it is an important measure to increase the content of the carbonate bounded zinc and the organic matter loosely bounded zinc in soil.