土壤有机质对有效磷及水提取磷含量的影响

Effect of soil organic matter on the contents of availableand water-extracted phosphorus

  • 摘要: 为了解土壤有机质对有效磷与总磷、水提取磷与有效磷关系的影响, 采用田间调查的方法, 对洛阳市郊主要农田4种土壤耕作层土壤进行取样调查, 并采用常规土壤测试方法, 分别测定土样有机质、全磷、有效磷和水提取磷含量。根据有机质含量(高于或低于16.0 g·kg-1)把土样分成两组, 对两组土样的总磷与有效磷、有效磷与水提取磷分别做相关关系分析。结果表明: 与低有机质土样组相比, 高有机质土样组有效磷与总磷相关方程的斜率较大, 水提取磷与有效磷相关方程的斜率较小, 这一趋势在以Olsen法和Mehlich-3法测定有效磷时均相同。表明在缺磷环境中, 有机质增加条件下, 虽然磷的生物有效性降低, 但有助于在土壤溶液中维持相对较高的磷酸根浓度, 这可能是由于磷的周转加快; 随着土壤磷含量增加, 有机质增加有助于更快提高磷的生物有效性, 但土壤溶液中维持相对较低的磷酸根浓度, 这可能有助于减轻农田磷的渗漏流失。

     

    Abstract: A total of 40 soil samples of 4 soil types were collected in cultivated farmlands in the outskirts of Luoyang and analyzed using conventional methods for the effects of soil organic matter content on the concentrations of available phosphorus, total phosphorus and water-extracted phosphorus. Based on soil organic matter content less/greater than 16.0 g·kg-1, the soil samples were divided into two groups, and the relationships between available and total phosphorus, and water-extracted and available phosphorus in the two groups estimated. The results showed that the slope of linear correlation between available and total phosphorus was higher in soil sample group with >16.0 g·kg-1 organic matter content than the group with <16.0 g·kg-1 organic matter content. Also the slope of linear correlation between water-extracted and available phosphorus was lower in the >16.0 g·kg-1 organic matter group than in the <16.0 g·kg-1 organic matter group. This trend was shown in both the Olsen and Mehlich-3 extraction methods. The study showed that under low soil phosphorus, high content of soil organic matter meant less soil available phosphorus. This also resulted in high water-extracted phosphorus concentration. It in turn meant that in soils with high organic matter content and low phosphorus, phosphorus recycle was much faster. When soil phosphorus content increased, available phosphorus concentration increased more rapidly in soil samples with high soil organic matter. Meanwhile, water-extracted phosphorus increase was relatively slow. The study throw further light on the need and strategies of reducing leaching loss of phosphorus.

     

/

返回文章
返回