Relationship between phosphorus fractions of some selected Sudanese soil orders to phosphate availability

Authors : Abdel Wahab Ahmed Mohamed AHMED, Mohammed Abdalla ELSHEİKH, Yousif El Gorashi EL MAHİ

Pages : 224-229

Doi:10.18393/ejss.421609

View : 13 | Download : 6

Publication Date : 2018-07-01

Article Type : Research Paper

Abstract :A laboratory experiment was conducted to determine the extent and the importance of phosphorus insert ignore into journalissuearticles values(P); fractions of some agriculturally important Sudanese soils on P availability. The soils were gathered from different locations in Sudan, to represent three different orders: Aridisols insert ignore into journalissuearticles values(Um Dum soil, North Kordofan state);, Alfisols insert ignore into journalissuearticles values(Hagu soil, Senar state);, and Vertisols insert ignore into journalissuearticles values(Hosh soil, Gezira state);. The soil P was fractionated using an authenticated procedure. The results showed that the soils had low total, organic and available P contents. Most of the inorganic soil P was present in the Fe-Al fraction in Um Dum soil insert ignore into journalissuearticles values(> 50%);, and about 40% of this fraction in Hagu soil, but, only 20% in alkaline Hosh soil. The Ca-P fraction constituted > 60% in Hosh soil, about 40% in Hagu soil and 20 % in Um Dum soil.  The available P in the top soils studied was positively related to the percent sum of Al+Fe -P of the total P, and was negatively related to the percent Ca-P fraction content of the total P. It has been proposed that the P sorption starts by exchange with singly coordinate Fe or Al- OH clay insert ignore into journalissuearticles values(OH − edge group ); and quickly reorganizes into more stable and less soluble ring forms especially at pH more than 7.0, Alkaline pH more than 8.0 in soil like Hosh, will in presence of Ca, favour with time, the formation of inactive less soluble form like octacalcium phosphates and apatites at expense of the initial Al and Fe-P forms which are less stable at alkaline pH.
Keywords : Phosphorus forms, total phosphorus, organic phosphorus, inorganic phosphorus, available soil phosphorus, Sudanese soils