Spectroscopic quantification of soil phosphorus forms by 31p-nmr after nine years of organic or mineral fertilization

Luciano Colpo Gatiboni,Maria Angélica Silveira Lima,Danilo Dos Santos Rheinheimer,Milton Veiga,Carla Maria Pandolfo,João Kaminski,Gustavo Brunetto,Alex Fabiani Claro Flores,Eduardo Girotto,André Carlos Cruz Copetti

doi:10.1590/s0100-06832013000300010

Luciano Colpo Gatiboni, Maria Angélica Silveira Lima + Show 8 more

Open Access

https://doi.org/10.1590/s0100-06832013000300010

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Abstract

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.

Highlights

Much of the organic waste generated on rural properties is potential fertilizer
An increase in P availability after fertilization was confirmed. This indicates that the amount of P added was higher than the P exported by crops, promoting accumulation in the soil. It can be observed (Table 1) that the levels of available P in the soil were related with P added via organic and mineral fertilizers because in treatments with higher P addition, more available P was found after nine years of experiment
Higher acidification was observed in the mineral fertilizer treatment and pH increase or no acidification was observed after organic fertilization

Summary

Introduction

Much of the organic waste generated on rural properties is potential fertilizer. In the recent past, the use of agricultural residues has become more attractive because of the increasing importance of the organic agriculture model, which recommends the use of non-industrialized and low energy-cost nutrient sources (Mäder et al, 2002). Of the waste generated on farms, the most common is animal manure, widely used as fertilizer. These materials must be used with caution, because if applied excessively, soil nutrients can be accumulated, nitrogen (N) and phosphorus (P), above the soil adsorption or plant uptake capacity, posing contamination risks as nonpoint pollution sources with high nutrient transfer capacity to aquatic systems (Sharpley et al, 1995). Soil organic P is a nutrient reservoir that can become available to plants and soil microbial biomass (Gatiboni et al, 2008). E.g., in inorganic forms, organic P can be transferred from soil to water bodies and contribute to the nutrition of aquatic organisms, including cyanobacteria, which can cause eutrophication (Sharpley et al, 1995)

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