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%...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.展开更多
A field test with the traditional rotation of paddy rice/upland crop (wheat) was carried out on a paddysoil derived from red earth to elucidate the effect of organic manure on the phosphorus adsorption-desorptionby so...A field test with the traditional rotation of paddy rice/upland crop (wheat) was carried out on a paddysoil derived from red earth to elucidate the effect of organic manure on the phosphorus adsorption-desorptionby soil and its P availability Soil samples were taken from different treatments at rice harvesting stage andanalysed. The isothermal adsorption of P by the samples fitted very well with Langmuir equation, and hence,the parameters in the equation, i.e., maximum adsoaption (qm), constant related to bonding energy (k) andtheir product (k x qm) could be used as a comprehensive index to characterize the potential P adsorptivityof the soil.Organo-inorganic fertilization and organic manuring conld decrease qm and k, while mineral P appli-cation had little effect on them. The isothermal desorption of P was significantly correlated with initiallyadded and isothermally adsorbed P. Part of P added was fixed, which represented the P fixation capacityof soil, and organic manuring could obviously lower the P fixation. The content of soil available P had asignificant negative correlation with qm, k and fixed P. It is concluded that organic manure could increase theP availability of paddy soil derived from red earth by decreasing qm, k, maximum buffering capacity (MBC=k x qm) and fixation capacity.展开更多
INTRODUCTION The insoluble phosphates which can not be directly absorbed by plants are the mai forms of inorganic phosphate in soil. These kinds of phosphates can be solubilized by several species of bacteria which ar...INTRODUCTION The insoluble phosphates which can not be directly absorbed by plants are the mai forms of inorganic phosphate in soil. These kinds of phosphates can be solubilized by several species of bacteria which are widely spread in soil especially in rhizosphere where70% of the bacteria are capable of solubilizing inorganic phosphate. Many researchers re-展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘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.
文摘A field test with the traditional rotation of paddy rice/upland crop (wheat) was carried out on a paddysoil derived from red earth to elucidate the effect of organic manure on the phosphorus adsorption-desorptionby soil and its P availability Soil samples were taken from different treatments at rice harvesting stage andanalysed. The isothermal adsorption of P by the samples fitted very well with Langmuir equation, and hence,the parameters in the equation, i.e., maximum adsoaption (qm), constant related to bonding energy (k) andtheir product (k x qm) could be used as a comprehensive index to characterize the potential P adsorptivityof the soil.Organo-inorganic fertilization and organic manuring conld decrease qm and k, while mineral P appli-cation had little effect on them. The isothermal desorption of P was significantly correlated with initiallyadded and isothermally adsorbed P. Part of P added was fixed, which represented the P fixation capacityof soil, and organic manuring could obviously lower the P fixation. The content of soil available P had asignificant negative correlation with qm, k and fixed P. It is concluded that organic manure could increase theP availability of paddy soil derived from red earth by decreasing qm, k, maximum buffering capacity (MBC=k x qm) and fixation capacity.
基金Projcct supponcd by the National Natural science Foundation of China.
文摘INTRODUCTION The insoluble phosphates which can not be directly absorbed by plants are the mai forms of inorganic phosphate in soil. These kinds of phosphates can be solubilized by several species of bacteria which are widely spread in soil especially in rhizosphere where70% of the bacteria are capable of solubilizing inorganic phosphate. Many researchers re-
