Effect of tillage methods on inorganic phosphorus forms in huangmian soil

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 Huangmian soil. Fractionated by Jian-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-PAl-P Fe-PCa2-P. ② Compare 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 Ca8-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.