Study on structural characteristics of pillared clay modified phosphate fertilizers and its increase efficiency mechanism

Abstract

Three types of new high-efficiency phosphate fertilizers were made when pillared clays at certain proportions were added into ground phosphate rock. Chemical analyses showed that their soluble phosphorus content decreased more than that of superphosphate. Pot experiment showed that, under equal weights, the new fertilizers increased their efficiency by a large margin over that of superphosphate. Researches on their structures by means of XRD, IR and EPR spectrum revealed that their crystal structures changed considerably, improving their activity and preventing the fixation of available phosphorus in the soil, and consequently, greatly improved the bioavailability and became the main cause of the increase of biomass.

Phosphorus Availability and Release Pattern from Activated Dolomite Phosphate Rock in Central Florida

“…; the peak at 879 cm −1 was the elastic vibrating ν 2 absorption pattern of CO 3 2− ; the peaks at 1095 and 1046 cm −1 were the antisymmetrical elastic vibrating ν 3 absorption patterns of PO 4 . 35 Compared with those of DPR, the strongest absorption peak of AP1 and AP3 showed a red shift. The peak at 469 cm −1 in the spectrum of AP3 was weakened, with several weak peaks nearby, and the characteristic peaks of CO 3 2− at 1456 and 1432 cm −1 were weakened in the spectra of AP2 and AP3.…”

“…In the FTIR spectrum of DPR (Figure ), the peaks at 1456 and 1432 cm –1 were the antisymmetrical elastic vibrating ν 3 absorption patterns of CO 3 2– ; the peak at 879 cm –1 was the elastic vibrating ν 2 absorption pattern of CO 3 2– ; the peaks at 1095 and 1046 cm –1 were the antisymmetrical elastic vibrating ν 3 absorption patterns of PO 4 3– ; the peak at 966 cm –1 was the symmetrical elastic vibrating ν 1 absorption pattern of PO 4 3– ; the peaks at 603 and 569 cm –1 were the bending vibrating ν 4 absorption patterns of PO 4 3– ; and the peak at 469 cm –1 was the elastic vibrating ν 2 absorption pattern of PO 4 3– . Compared with those of DPR, the strongest absorption peak of AP1 and AP3 showed a red shift.…”

Pilarização de argilas e perspectivas de aplicação e de pesquisa agronômica e ambiental

“…CHIRCHI & GHORBEL (2002) No âmbito da produção agrícola, que refl ete diretamente nas questões ambientais, ações que visem à exploração racional dos recursos naturais são necessárias, situação que também oportuniza a abertura de linhas de pesquisa para o estudo das argilas pilarizadas. Trabalhos como os desenvolvidos por WU & LIAO (2005) e GERSTL et al (1998 são exemplos disso. O primeiro mostra que é possível aumentar a efi ciência no uso de fertilizantes fosfatados ao misturar, nas devidas proporções, argilas pilarizadas junto às rochas fosfatadas moídas, aumentando a biodisponibilidade em longo prazo e minimizando a fi xação de fósforo no solo.…”

Solubility and Efficiency of Rock Phosphate Fertilizers Partially Acidulated with Zeolite and Pillared Clay as Additives

“…In the processing of partially acidulated phosphates, a small amount of sulfuric or phosphoric acid reacts with RP in order to breakdown part of the hydroxyapatite (insoluble P) into monocalcium phosphate (soluble P), and thereby obtain a fast dissolution product [9]. Moreover, the incorporation of minerals with high phosphate adsorption capacity and/or high cation exchange capacity (CEC), such as pillared clays (PILC) and zeolites, into partially acidulated phosphates shows promise to improve agronomic efficiency [10,11]. The premise is that the initial P release will saturate the acidic sites of the PILC before adsorption, which act as a vehicle for slow and gradual dissolution into soil solution.…”