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18个供试土样,在较宽的磷浓度范围内(0—100μmP/g土),它们的吸磷特征与Langmuir,Freundli-ch和Temkin方程式都有很好的相关性(r值大多在0.97以上),尤以Langmuir方程式最佳。各供试土样吸磷能力差异很大,其最大M从大约300μg P/g土(黑垆土)到1500/μg P/g土(砖红壤),火山灰土则高达5000μg P/g土。当加入100μm P/g土时,上述各土壤吸磷量分别占加入磷量的10%,47%和95%左右。土壤粘粒含量以及无定形和结晶态游离氧化铁铝含量均各与M显著相关。土粒的比面可作为单一的指标,它能较妥切而综合地反映土壤的吸磷能力。有机质对土壤吸磷能力的影响是复杂的,它可以增加或减少M值。耕作施肥特别是红壤旱改水多年后,显著地降低了原土壤的M和K值。砂潮新成土上不同施肥处理小区的吸磷等温线表明,土壤中新增加的粗有机物质对磷的吸持作用多发生在磷浓度较高的范围内,它是以吸附量高而吸附结合能低为特征的。
Among 18 tested soil samples, their phosphorus uptake characteristics were well correlated with the Langmuir, Freundlich and Temkin equations over a wide range of phosphorus concentrations (0-100 μm P / g soil) 0.97 or more), especially the Langmuir equation. The phosphorus uptake capacity varies greatly for each test sample, with a maximum M ranging from about 300 μg P / g soil to 1500 μg P / g soil (brick red soil) and volcanic ash soil up to 5000 μg P / g soil. When 100μm P / g soil was added, the P uptake of each soil accounted for about 10%, 47% and 95% respectively. Soil clay content and amorphous and crystalline free iron oxide content were significantly correlated with M. Soil ratio can be used as a single index, which can more properly and comprehensively reflect the phosphorus uptake capacity of the soil. The effect of organic matter on soil P uptake is complex, and it can increase or decrease the M value. After many years of cultivation and fertilization, especially red soil drought and water change, the M and K values of the original soil were significantly reduced. The phosphorus uptake isotherms of different fertilization treatments in the newly formed soil show that the adsorption of phosphorus by the freshly added crude organic matter in the soil mostly occurs in the range of high phosphorus concentration. The combination of low energy is characterized.