Produtividade de sementes de malva (urena lobata L.) em função de adubação química em terra firme em Manaus – AM

Abstract

Malva (Urena lobata L.) is one of the priority production chains for Amazonas as it is an income-generating crop in the region. Its fiber is mainly used to produce sacks and its cultivation is based on clean technologies, with extensive use of family labor. In this context, considering that seed quality is the basis of its production chain, the aim of the research was to evaluate the effect of chemical fertilization and its parceling on the production of mallow seeds. Firstly, a bibliometric analysis was carried out on the cultivation and production of mallow seeds. The experiment was conducted at the Experimental Farm of the Federal University of Amazonas. The experimental design was randomized blocks (DBC) with six fertilizer management treatments and four replications: T1 = no fertilization; T2 = limestone; T3 = 30 kg.ha-1 of N, 100 kg.ha-1 of P2O5, and 100 kg.ha-1 of K2O; T4 = 40 kg.ha-1 of N, 80 kg.ha-1 of P2O5, and 80 kg.ha-1 of K2O; T5 = 30 kg.ha-1 of N, 100 kg. ha-1 of P2O5, and 100 kg. ha-1 of K2O, with top dressing applied at the 5th month and T6 = 40 kg.ha-1 of N, 80 kg.ha-1 of P2O5, and 80 kg.ha-1 of K2O, with top dressing applied at the 5th month. The bibliometric analysis indicated that the state of Amazonas, as well as being the main producer of mallow fiber in the country, is a leading producer of studies aimed at understanding the agronomic aspects of the crop. The flowering period began 145 days after transplanting (DAT). The crop was harvested at 275 DAT. With regard to the effect of chemical fertilization and its distribution on seed yield, treatment T5 = 30 kg.ha-1 of N, 100 kg.ha-1 of P2O5, and 100 kg.ha-1 of K2O with top dressing at the 5th month, produced an average of 90 g pit-1 and had a seed yield of 1637.1 kg.ha-1. We suggest that further studies be carried out relating chemical fertilization to mallow seed yield, including applications of boron (B) and calcium (Ca) to the plants. With regard to seed quality, the treatments applied in this study had no significant effect on the physical and physiological quality of the seeds. In this study, it was possible to observe that during the germination test of mallow seeds, after pre-germination treatment, a single evaluation is sufficient, on the 5th day after germination, as seedling development can already be seen during this period.