Produção de milho e cártamo em sucessão após aplicação ao solo de biochar e extrato pirolenhoso de eucalipto

Abstract

The growing demand for sustainable and low-cost agricultural practices has encouraged research into alternatives to improve crop yield and quality, especially in semi-arid regions. The objective of this research was to investigate the production of Carthamus tinctorius L. (safflower) and Zea mays L. (maize) in soils treated with different doses of two types of biochar from eucalyptus. The experimental design was in randomized blocks, which tested the effects of two factors: biochar dose (0, 3, 6 and 9 t ha-1) and type of biochar (pure, or soaked with 30% wood vinegar - WVbiochar), and also the interaction between them. The importance of optimizing biochar dosages was evidenced in the first season by its significant effect on the number of capitula per plant (NCAP), grain yield (PROD) and oil yield (ROL), which, in relation to the control, were higher at the dose of 3 t ha-1, followed by 6 t ha-1. In the second season, the effect of dose was significant for the number of seeds per chapter (NSEM) and NCAP, with higher values for 6 t ha-1. There was no effect of the use of WVbiochar in the first season, however, in the second, it provided higher NSEM and the interaction with the dose was significant for weight of one thousand seeds (MILSEM) and ROL, for which the dose of 9 t ha-1 provided higher values, with biochar in MILSEM and with EPbiochar in ROL. In the corn crop, the biochar dose provided a quadratic effect on the insertion height of the first ear, grain weight in ten ears, and yield per hectare, whose maximum values were obtained with doses of 3.5, 7.2 and 6.6 t ha-1, respectively. These last two variables showed higher values when WVbiochar was applied. Thus, it was found that, in adequate doses, biochar and WVbiochar can benefit the growth and yield of these crops and the oil content of safflower. Agricultural practices involving the proper use of these conditioners can represent a viable, low-cost, and sustainable alternative for smallholder farmers, especially in agricultural systems of semi-arid regions.