Fertilidade do latossolo amarelo textura média sob cultivo intensivo de plantas alimentares no nordeste paraense

Abstract

Some properties of a loamy oxisol of the northeastern of the Pará state under continuous crops of rice-corn-cowpea were determimed after two years of manure or chemical fertilizer applications. A split-plot experimental design was used with organic compost and an NPK formula as treatments and depth of soil sampling (0 - 10 cm and 10 - 20 cm) as sub treatments, with four replicates. Chemical properties determined were pH, exchangeable bases (Ca+Mg, K and Na), exchangeable acidity (H+Al), P and C; physical properties were granulometry, particle density, bulk density and porosity of the soil. Results showed that organic compost and NPK application improved the chemical properties of the soil, but they did not affect the physical variables measured. There was an interaction between treatments and depth of soi! sampling. There was a significative correlation (p <0,05) between yields of corn or cowpea with available P (R = 0,60 to 0,76), pH (R = 0.47 to 0, 58) and exchangeable K (R =0,55 to 0,77). Physical properties of the soil were not correlated with harvest of either corn or cowpea.