Soil chemical properties, growth and production of sunflower under fertilization with biochar and NPK.

The use of biomass can contribute to improve the soil properties. The objective of this study was to evaluate the effect of fertilization with poultry litter biochar in combination with mineral fertilizer on soil chemical attributes, growth and yield components of sunflower. For this purpose, a greenhouse experiment was carried out in pots with a capacity of 20 dm3 under randomized design, with treatments arranged in a factorial 5 × 4 design with four replicates. The treatments consisted of five doses of mineral fertilizer (0, 25, 50, 75 and 100% fertilization recommendation) with NPK (100, 300, and 150 mg kg-1) and four doses of biochar of poultry litter, 0; 5% (400 g/pot); 10% (800 g/pot) and 15% (1,100 g/pot) calculated based on the volume of the soil. The results showed that fertilization with poultry litter biochar of 400 g/pot, increased soil salinity of the experimental units. Besides, there was a reduction in the number of leaves (NL), plant height (PH), stem diameter (SD) and number of achenes for each head (NAH). Fertilization with 50% of NPK recommendation (50:150:75 mg kg-1) produced the highest growth and yield components of sunflower, compared with other NPK treatments. The combination from 50:150:75 mg kg-1 (50%) of NPK fertilization and 1,100 g/pot of poultry litter biochar promoted larger head diameter (HD) of sunflower