栗钙土中磷肥转化及效应的研究

采用石灰性土壤无机磷的分级方法,研究了磷肥在栗钙土中的转化以及包被物对土壤中磷肥转化的影响和莜麦的磷肥效应。研究结果表明,在不种作物的情况下,磷肥施入土壤后很快转化为Ca_2-P、Ca_8-P、Al-P、Fe-P等形态,随施肥时间的延长,Ca_2-P呈减少趋势,其它形态的无机磷则逐渐增加;在种植莜麦的情况下,莜麦对磷肥的吸收利用率为31.1％,土壤残留为68.9％,残留磷中各形态无机磷占施入磷的比率:28.9％为Ca_2-P,11.0％为Ca8-P,10.3％为Al-P,5.5％为Fe-P,9.5％为O-P,3.7％为Ca_(10)-P;包被磷肥较未包被磷肥减少了土壤中Ca_2-P向Ca_8-P转化,增加了施入磷向Al-P的转化而减少了向Fe-P、O-P的转化,磷肥的利用率提高2.9个百分点。施用磷肥莜麦增产178％。

蔬菜保护地土壤磷肥动态转化及其影响因素研究

以两种磷素水平不同的菜地土壤为研究对象 ,采用培养和盆栽试验法 ,系统研究了磷肥的动态转化、影响因素及其磷肥的效应。结果表明 ,高磷土壤的磷肥固定率明显低于低磷土壤 ,施入土壤中的磷肥大部分在初期被固定。有机肥在培养初期增加磷肥的固定率 ,到后期减小磷肥的固定率。低磷土壤施用磷肥和有机肥 +磷肥两处理具有明显的增产效果 ;而高磷土壤施用磷肥和有机肥 +磷肥两处理无明显增产效果。高磷土壤油菜生物量明显高于低磷土壤。随着种植茬数的增加 ,土壤Olsen

腐植酸对磷肥转化机理的探讨

一、前言 腐植酸类肥料是 一种广泛适应我国土壤的好肥料,他兼备了无机肥料的速效性和有机肥料的持久性两大优点,且投资少,收效快,适合我国广大农村农户使用,本肥仍具有改良土壤,缓冲土壤的pH值,使农作物在更适宜的酸度环境生长,对改良我国北方兰考县式的盐碱地将有特殊功效。

小麦-玉米轮作土壤中磷肥化学行为及积累态磷生物有效性的研究

本文用改进的石灰性土壤无机磷分级方法系统地研究了河北省主要类型土壤的磷素形态，小麦玉米轮作中水溶性磷肥施入土壤后的动态转化。研究结果表明，潮褐土、褐土、潮土的磷素形态为：无机磷占土壤全磷的７３２％～９６４％，ＣａＰ占无机磷的７９１％～９０８％，Ｃａ１０－Ｐ占ＣａＰ的５１７％～９７４％。小麦玉米轮作中水溶性磷肥施入土壤后的化学行为：第一年，小麦和玉米共吸收利用了施入磷的２４６％～２７４％，作物主要消耗了土壤积累态Ｃａ２－Ｐ，其次为Ｃａ８Ｐ；第二、三年，作物分别吸收利用了施入磷的１９０％～２０４％、１２４％～１７３％，主要消耗了土壤积累态Ｃａ８Ｐ，其次为Ｃａ２Ｐ、ＡｌＰ，再次为ＦｅＰ。土壤积累磷以Ｃａ８Ｐ为主，其次为Ｃａ２Ｐ，再次为ＡｌＰ、ＦｅＰ。土壤各形态无机磷的转化主要发生在Ｃａ２Ｐ与Ｃａ８Ｐ之间。化学磷肥与有机肥配施提高了土壤积累态磷的有效性。施用磷肥的效应在连续３年小麦玉米轮作中均表现明显的增产效应。

Influence of Organic Manure on Organic Phosphorus Fraction in Soils

The transformation of organic P(Po) from organic manures in two types of soils (ultisol and entisol) and the influences of external addition of organic substance or inorganic P(Pi) on Po under the condition of the 60% maximum water capacity were investigated.The results obtained from Po fractionation experiments indicated that all the Po fractions except for the highly resistant Po fraction decreased during incubation.Application of pig feces and cow feces could largely increase each fraction of Po in the soils.Immediately after application of organic manure into the soils a large part of labile and moderately labile Po from organic manure was transferred into moderately resistant Po,which might be due to the fact that Ca-or Mg-inositol P was precipitated into Fe-inositol P.However,the availability of Po from organic manure in the soils would increase again after incubation because of the transformation of moderately labile and resistant Po fractions into labile Po fractions.Addition of cellulose or Pi into the soils showed a good effect on increasing all the Po fractions except for the highly resistant Po,and this effect was much more pronounced when cellulose was applied in combination with Pi.Therefore,in view of the effect of organic manure on improving P nutrition to plant,attention should be paid to both the Po and the organic substances from organic manure,It is suggested that application of Pi fertilizer combined with organic manure may be referred to as an effective means of protecting Pi from chemical fixation in soil.

Transformation of Phosphate Fertilizers with Different Solubilities in Calcareous Soils

In this research work, the authors, using the recently developed method of fractionating the forms of inorganic phosphorus in calcareous soils, have studied the transformation processes of inorgnic phosphorus in three different phosphate fertilizers, i. e., superphosphate, diammonium phosphate and calcium magnesium phosphate, being commonly used in China, during a period of 3 years after their application to calcareous soils, and based on the experimental results obtained, some problems in current use of phosphate fertilizers are discussed.

Transformation of Applied Phosphorus in a Calcareous Fluvisol

A new inorganic phosphorus (IP) fractionation scheme developed by Jiang and Gu was used in an incubation experiment to investigate the transformation of applied P in a calcareous fluvisol. The results show that after addition of common superphosphate (CSP), the Ca2-P in the soil decreased gradually and transformed largely to the less available Fe-P, Al-P and Ca8-P, rather than to the unavailable forms of Ca10-P and O-P. The different IP fractions ranked in the following order with respect to the increment by addition of CSP after 120 days of incubation: Fe-P> Al-P>Ca8-P>Ca2-P. After addition of pig manure, the content of Ca2-P in the soil increased rapidly at first and then decreased slowly, and the amount of different IP fractions accumulated after 120 days of incubation ranked in the following order: Ca2-P > Fe-P > Ca8-P > Al-P. Evidently, the variation in content of Ca2-P and the order of increase in different IP fractions in incubation induced by application of pig manure were quite different from that of CSP. The increase in IP fractions in the incubation of broad bean green manure (BBGM)for 120 days was in the rank of Fe-P > Ca2-P > Ca8-P > Al-P; but because organic phosphorus (OP) of BBGM degraded relatively slowly, the increment in IP fractions was lower than that of pig manure. Wheat straw was difficult to mineralize and induced a strong biological fixation of soil P, resulting in a decrease of the content of Ca2-P, even Ca8-P, Fe-P and Al-P.

Transformation and Availability of Various Forms of Zinc in Soils

The transformation and availability of various forms of Zn applied into a cinnamon soil and a carbonate meadow soil as well as the effects of fertilizer-P on them were studied by using the field experiment method and chemically sequential extraction procedure. Zn added into the soils was found to be rapidly transformed into the various forms. In the cinnamon soil, the amount of Zn transformed into the carbonate bound form was the highest, and the carbonate bound form was proven by the analyses of intensity factor and capacity factor to be the primary available Zn pool.But in the carbonate meadow soil, the Zn transformed was relatively homogeneously distributed in the various forms though the amount of Zn transformed into the Mn-oxide bound form was relatively high, and the organically bound, Mn-oxide bound and amorphous Fe-oxide.bound forms were found to be the main available Zn pool. Fertilizer-P took part in the regulation and control of available Zn in the soils to a certain degree. In the carbonate meadow soil, application of P fertilizer probably aggravated Zn deficiency at low Zn rate, while it was favorable to the storage of available Zn in the case of high Zn rate.