ABSTRACT The use of organic fertilizers from pig slurry and poultry litter can increase soil organic carbon and crop productivity. This study aimed to evaluate soil organic carbon fractions and corn yield after applying organic and mineral fertilizers. The experiment was conducted in the western region of Santa Catarina State, southern Brazil on a Nitossolo Vermelho Eutroférrico típico (Rhodic Kandiudox). The production system was an integrated crop-livestock using corn and soybean in the summer and black oat and rye with grazing by sheep in the winter. The experimental design was randomized blocks, with treatments in factorial 5 × 3 + 1, with four replications, five sources of fertilizers, three rates and the control with no fertilization. The treatments were three organic fertilizers: poultry litter, pig slurry and compost from pig slurry and two minerals fertilizer (M1 and M2). Mineral fertilizers were formulated from pig slurry (M1) and poultry litter (M2), with the application of three rates, which represent 75, 100 and 150 % of the recommendation for the crop, based on the element that is most demanding by the plant (K for soybeans and N for corn). Soil samples were collected at the layers of 0.00-0.05, 0.05-0.10 and 0.10-0.20 m in which fractions of total soil organic carbon (TOC), namely particulate (POC) and mineral-associated organic carbon (MAC) were determined. Corn yield was evaluated in the 2018/2019 and 2019/2020 seasons. The results were analyzed through analysis of variance to compare sources and polynomial regression analysis for fertilizer rates. The MAC fraction has a higher proportion of TOC and its contents were higher with increasing rates of organic and mineral fertilizers, mainly in the surface layer. Poultry litter and compost fertilizers increased TOC’s particulate fraction (POC), showing the highest levels at the highest fertilization recommendation rate. Organic and mineral fertilizers positively increase corn yield, and animal-derived fertilizers show that they can be an alternative for high crop yields.

ABSTRACT The objective of this study was to evaluate how the fertilizer composition, type and application method contribute to the initial growth of Pinus taeda applied at planting. Seedlings from an open-pollinated seed orchard of Pinus taeda were planted on a Humic Dystrudepts soil containing 15 treatments of fertilizer application at planting. Basal diameter (immediately above ground – about 5 cm) and total height were measured on all live plants after six, 12 and 42 months. The basal diameter at six and 12 months ranged from 0.49 to 0.63 cm and 1.64 to 2.15 cm, respectively. The height at six and 12 months ranged from 0.49 to 0.64 m and 0.77 to 1.01 m, respectively, indicating that fertilizing improved this characteristics in ~30%. Fertilizer composition, type and application method contributed to the first year of growth of Pinus taeda. Nevertheless, fertilization response disappeared after 42 months.