不同土地利用方式下土壤无机磷形态与酶活性空间变异特征

Spatial Variation of Soil Inorganic Phosphorus Forms and Soil Enzyme Activities Under Different Land Use Types

对陇东黄土高原不同土地利用方式下黄绵土和黑垆土土壤磷形态、无机磷形态和土壤酶活性的空间分布特征及其相关性进行了研究。研究结果表明,土壤无机磷(Pi)含量随土层加深均呈下降趋势;有机磷(Po)含量在果园黒垆土和菜园土中呈下降趋势;农田、苜蓿地全磷(TP)含量随土层加深呈上升趋势;各利用方式0—20 cm,20—40 cm土层速效磷(Pol)与TP,Po呈极显著的正相关。各无机磷形态平均含量依次为Ca10—P>Ca8—P>Al—P>Fe—P>Ca2—P>O—P。黄绵土利用中Ca8—P,Al—P和Ca2—P随土层加深呈下降趋势。黑垆土农田、果园和菜园土则呈上升趋势。土壤酶活性与土壤无机磷形态相关性强弱依次为:果园>菜园>农田、撂荒地>沙棘林、苜蓿地、烤烟地;与酶活性的相关性强弱的无机磷形态依次为Al—P>Ca10—P>Ca2—P>Ca8—P>Fe—P,O—P。

Spatial distribution and correlation of soil phosphorus, inorganic phosphorus forms, and enzyme activities in loessial soil and dark loessial soil under different land uses were studied on the Loess Plateau of Gansu Province. Results showed that as the depth of soil layer increased, inorganic phosphorus decreased, as well as organic phosphorus in dark loessial soil in orchard and vegetable garden. However, total phosphorus in farmland and alfalfa land increased with increased soil depth. There was a very significantly positive correlation between soil phosphorus and organic phosphorus in 0-20 and 20-40 cm soil layers for each land use type, as well as between soil phosphorus and total phosphorus. In terms of the average inorganic phosphorus content, Cal0--P, Cas P, A1--P, Fe--P, Ca2---P, and O--P were ranked in descending order. As the depth of soil layer increased, Ca8 P, Al-P, and Ca2--P in loessial soil decreased, but they increased in dark loessial soil in orchard, farmland, and vegetable garden. In terms of the correlation between soil inorganic phosphorus forms and enzyme activities, orchard, vegetable garden, farmland, wasteland, sea buck- thorn forest, and alfalfa and tobacco lands were ranked in descending order. In terms of the correlation between soil inorganic phosphorus and soil enzyme activities, Al-P, Ca10-P, Ca2-P, Ca8--P, Fe-P, and O-P were ranked in descending order.