2 results

Organic phosphorus in soils under cocoa agrosystems

Francisco Costa Zaia, Antonio Carlos da Gama-Rodrigues, Emanuela Forestieri da Gama-Rodrigues, Regina Celes Rebouça Machado

01/Oct/2008

Understanding the soil organic P (Po) cycle is important to improve the P fertilization management in low-input tropical agricultural systems. The aim of this study was to evaluate Po content and labile P fractions, and microbial biomass P in soils under different cocoa agroecosystems. Mean total Po was 193 mg kg-1 and accounted for 7.8 to 36.3 % of the total extracted P. Mean labile Po was 15 mg kg-1 and accounted for 33.1 to 81.9 % of the total labile P. In cocoa agrosystems, the […]

Organic phosphorus in soils under montane forest, pasture and eucalypt in the North of Rio de Janeiro State, Brazil

Gláucio de Mello Cunha, Antonio Carlos da Gama-Rodrigues, Gilmar Santos Costa, Ary Carlos Xavier Velloso

01/Aug/2007

Highly weathered tropical soils have low P plant availability and very high inorganic phosphorus (Pi) adsorption capacity. Therefore, maintenance of organic sources able to supply P by mineralization is essential for P availability under highly weathered conditions. Organic matter cycling and tolerance to low P soil concentration of the plant community may guarantee sustainability in natural ecosystems. The aim of this study was to evaluate organic phosphorus (Po) content and labile P fractions in the soils of three sites. The […]