Avaliação do desenvolvimento inicial de cultivar de maracujazeiro amarelo (Passiflora edulis) com diferentes doses de estruvita extraída do efluente bruto da piscicultura

Abstract

According to UN data (2019), the world population will continue to grow, and by 2050 it will reach 9.7 billion people, and the production of enough food for everyone remains one of the central concerns. Thus, it is necessary to develop mechanisms that enable production capable of meeting population needs, associated with environmental preservation. In this context, struvite extracted from the effluent from fish farming is an alternative to supply phosphorus to plants, without depleting the mineral reserves used in the manufacture of fertilizers. In addition, it is necessary to encourage the production of crops that make it possible for people to remain in the countryside, generating jobs and income throughout most of the year, such as passion fruit. Therefore, the present study aimed to evaluate the initial development of passion fruit seedlings submitted to different doses of struvite extracted from psiculture. This research is exploratory and experimental, being the first agronomic test carried out with material extracted from psiculture. The precipitation of struvite was carried out at the laboratory of Chemistry Applied to Toxicology, Environmental Sanitation and Water Resources of UFOPA, in Santarém. The agronomic experiment took place in the greenhouse II, at the University Campus of Juruti (CJUR/UFOPA), in DIC, with 5 treatments and 6 repetitions each. The passion fruit cultivar used was the hybrid BRS Gigante Amarelo, and the treatments followed the fertilization recommendation of the state of Pará for the crop: T1 - 100% struvite dose; T2 - 50% of struvite dose; T3 - 100% of the NPK dose (with the same struvite phosphorus proportions); T4 - 50% of the NPK dose; and T5 - witness (without application of fertilizer). Plants were evaluated weekly for 45 days, regarding height, number of leaves and stem diameter. At 44 days, gas exchanges (A, Gs and E) were measured. And, at 45 days, using destructive methodology, the fresh and dry mass of the shoot and root, the root volume and the number of lateral shoots were measured. Data were submitted to analysis of variance, and comparison of means was performed using the Tukey test, in the SISVAR software. In general, the results obtained show that struvite derived from psiculture is a viable alternative for the supply of phosphorus for the passion fruit crop, since it presented satisfactory results related to the development of the plants. However, treatments T1 and T2, with 100% and 50% struvite, showed a greater number of shoots, leaf chlorosis and a greater amount of phosphorus available in the soil. By associating these variables, it is possible that there was an excess of phosphorus in the plants, causing such symptoms. In view of this, additional tests with smaller proportions of struvite extracted from fish farming are necessary to evaluate the type of phosphorus available to the plants, as well as the appropriate dosage for the passion fruit crop.