Wood-Vinegar-Added Biochar as a Soil Conditioner Enhances Safflower Performance in the Brazilian Semi-Arid Northeast

Food security is threatened in the semiarid region of Brazil, which is susceptible to climate change and has low-fertility soils degraded by inadequate agricultural practices. This study aimed to evaluate safflower’s adaptation to the region and the benefits to the soil and crop of applying biochar and wood vinegar (WV). Biochar, pure or WV-added (Wv-biochar), was applied to the soil at doses of 3.0, 6.0, and 9.0 t ha−1. Determinations performed in three harvests of safflower were plant height, number of capitula per plant, number of seeds per capitulum, mass of 1000 seeds, seed yield, and oil content. The maximum safflower yields (1818.52 kg ha−1) and oil content (45.50%), and the average values of mass of 1000 seeds (35.55 g) were consistent with results reported in literature. Evidence of better performance of the variables under the effect of Wv-biochar than of pure biochar was observed, and, in general, the curves obtained showed quadratic behavior, with maximum values at intermediate doses. The seed yield and oil content achieved indicate that safflower is a promising crop for the region, particularly when more adapted genotypes and improved management practices are employed. The most pronounced effects on safflower production and oil content were observed at doses of 5 to 6 t ha−1 of Biochar and Wv-biochar, which are economical and sustainable alternatives due to their use of organic waste and the benefits they provide for soil and food security.