Soil Reaction And Plant Availability Of An Activated Phosphorus Rock Powder

As well known, elemental phosphorus is key and indispensable to agricultural production. Additionally, phosphorite is un-reproducible mineral resource and most of the arable lands across the world are seriously shortage of available phosphorus. All these results that elemental phosphorus is one of the most important limiting factor to China even the world's agricultural production and the supply and demand of phosphorous fertilizer is and will be a prominent contradiction. As we know well, the phosphorous in the low-grade phosphorite is difficult to utilize because they strongly combine with minerals, so how to make full use of them, to accelerate their release from the low-grade phosphorite and improve their effect almost same to the chemical fertilizer have the outstanding significance for the full using of China's phosphorite source and the sustainable development of agriculture. Based on this point, a study was proposed and conducted aiming at probing the techniques how to efficiently and fully utilize the phosphorous in low-grade phosphorite. First, the low-grade phosphate rock was remodeled to be the acidic phosphorite powder and the activated phosphorite powder, and then three kinds of phosphate rock powder were applied to soil and the effects were investigated and studied systematically. The main results and conclusions are followings:1) Preparation of activated phosphorite powderActivated phosphorite powder and acidic phosphorite powder were prepared by a methods of H₂SO₄ acidification and organic-inorganic agents activation, and several testing instruments including the scan electron-microscope (SEM), the X-ray diffraction (XRD) and the laser granularity, were used to measure sorts of the phosphorite powder. It was verified that more than 90% of the acidic phosphorite powder have a less than 4.227 μm of particle size, and more than 90% of activated phosphorite powder have a less than 220nm of particle size. Additionally, the crystallization of activated phosphorite powder declined, and the surface area of its increased.2) Soil reaction of activated phosphorite powderAll three tested phosphorite powder (natural phosphorite powder, acidified phosphorite powder, and activated phosphorite powder) positively affected the physical and chemical properties of red soil at different degree, with increasing the pH value, soluble phosphorus content and exchangeable Ca Mg content, weaking the fixation of available phosphorus, and decreasing the exchangeable Al content. The increased extent or decreased extent of the above items in red soil followed the order: activated phosphorite powder > acidic phosphorite powder > natural phosphorite powder. Additionally, the contents of all kinds of inorganic phosphorus in red soil increased significantly in the treatment with phosphorite powder compared with the control, especially, the contents of all kinds of inorganic phosphorus in the treatment of activated phosphorite powder were the maximal, and that in the treatment...