耕作方式对黄绵土无机磷形态的影响

Effect of tillage methods on inorganic phosphorus forms in Loessal soil

以设置在陇中黄土高原并已经进行了5年的田间定位试验为基础,采用蒋-顾石灰性土壤无机磷分级法,研究了不同耕作方式对黄绵土无机磷形态的影响。结果表明,供试土壤中78.6%的磷以无机磷形式存在,且以Ca-P占绝大多数。无机磷各形态含量排列顺序为:Ca1-0P>Ca8-P>O-P>Al-P>Fe-P>Ca2-P。与传统耕作不覆盖(T)相比,免耕秸秆覆盖(NTS)、免耕不覆盖(NT)、传统耕作结合秸秆还田(TS)均可降低土壤中的Ca8-P、O-P和0—5 cm土层中的Ca10-P含量,其中NTS最为明显;NTS处理可提高土壤中的Al-P、Fe-P含量。不同处理中,Ca2-P、Ca8-P、Al-P、Fe-P均以0—5 cm土层中含量最高,且随着土层的增加呈下降趋势;但是Ca10-P以5—10 cm土层含量最高;各处理O-P在土壤剖面中的变化没有显著差异。

By the Jiang-Gu inorganic phosphorus fractionation method, this paper studied the long-term （5 yrs） experiment was conducted to compare the effects of different tillage on in-organic phosphorus forms in Loessal soil. Fractionated by Jiang-Gu systerm .The results showed that： ① Inorganic P （Pi） occupied the most part of soil P and accounted for 78.6% on average. Of the total Pi, Ca phosphorus （Ca-P） was the do-minant Pi fractions and accounted for 78.4% on average. Pi fractions varied in the order of Ca10-P 〉 Ca8-P 〉 O-P 〉 Al-P 〉 Fe-P 〉 Ca2-P. ②Compare to conventional tillage （T）, the treatments of no-till with stubble reten-tion （NTS）, no-till without straw cover （NT） and conventional tillage with straw incorporated （TS） could decrease the content of Cas-P, O-P and Ca10-P that in the 0-5cm soil depth, NTS could increase the content of Al-P, Fe-P, but the content of Fe-P had no significance （P 〈 0.05） among the four treatments.③ Ca2-P, Ca8-P, Al-P and Fe-P tended to decline with the soil depth among the four treatments. Ca10-P accumulated in the 5-10 cm depth of the tested soil, O-P didn＇t show clear changes in the soil depth despite some fluctuation.