Spectroscopic quantification of soil phosphorus forms by 31p-nmr after nine years of organic or mineral fertilization
Estercos, Fertilizantes orgânicos, Fósforo orgânico, fitato, glicerofosfato
Long-standing applications of mineral fertilizers or types of organic wastes such as manure can cause phosphorus (P) accumulation and changes in the accumulated P forms in the soil. The objective of this research was to evaluate the forms of P accumulated in soils treated with mineral fertilizer or different types of manure in a long-term experiment. Soil was sampled from the 0-5 cm layer of plots fertilized with five different nutrient sources for nine years: 1) control without fertilizer; 2) mineral fertilizer at recommended rates for local conditions; 3) 5 t ha-1 year-1 of moist poultry litter; 4) 60 m³ ha-1 year-1 of liquid cattle manure and 5) 40 m³ ha-1 year-1 of liquid swine manure. The 31P-NMR spectra of soil extracts detected the following P compounds: orthophosphate, pyrophosphate, inositol phosphate, glycerophosphate, and DNA. The use of organic or mineral fertilizer over nine years did not change the soil P forms but influenced their concentration. Fertilization with mineral or organic fertilizers stimulated P accumulation in inorganic forms. Highest inositol phosphate levels were observed after fertilization with any kind of manure and highest organic P concentration in glycerophosphate form in after mineral or no fertilization.
Luciano Colpo Gatiboni, Gustavo Brunetto, João Kaminski, Danilo dos Santos Rheinheimer, Eduardo Girotto, Carla Maria Pandolfo, Milton Veiga, Alex Fabiani Claro Flores, Maria Angélica Silveira Lima, André Carlos Cruz Copetti