Produção de mudas de pequizeiro em resposta a aplicação de sulfato de cálcio e cloreto de sódio via água de irrigação

Abstract

The pequi tree (Caryocar brasiliense Camb.) is a fruit tree native to the Cerrado biome, of socioeconomic and environmental relevance. There is a growing demand for seedlings of the species for environmental recovery projects or the establishment of commercial orchards. However, the quality of irrigation water for seedling production is a fundamental aspect, as the presence of some salts in certain quantities can compromise plant development. In this sense, the present study aimed to evaluate the effect of irrigation water with different concentrations of calcium sulfate (CaSO4.2H2O) and sodium chloride (NaCl) on the development of pequi tree seedlings. Two experiments were conducted in a greenhouse, set up in a randomized block design with four replications in each. In the first, the treatments were concentrations of calcium sulfate (0; 144; 288; 433 mg L-1) and, in the second, sodium chloride (0; 110; 386; 800; 1,213 mg L-1). In both, additional treatment was adopted with groundwater (C2S1) from an artesian well, used for irrigation in the nursery for the production of fruit and native seedlings at UFMG/ICA. Assessments of soil fertility attributes, plant biometrics and nutrients in plant tissue were carried out. The increasing addition of calcium sulfate increased the growth of the aerial part of the plant, but reduced the dry mass of the root, hypocotyl and the Dickson seedling quality index. Furthermore, it also increased the content and content of phosphorus, calcium and sulfur in the leaf tissue and hypocotyl. Increasing doses of sodium chloride promoted a reduction in the dry matter of vegetative organs, stem height and diameter, low Dickson quality index and symptoms of chlorosis and necrosis, mainly from the concentration of 386 mg L-1 of NaCl. NaCl concentrations also compromised the chemical attributes of the soil, making the substrate saline and saline-sodic. The additional treatment, in both experiments, caused plant growth similar to treatments with zero dose of salts, despite providing a lower ratio of root and shoot dry mass. The research results indicate that C. brasiliense seedlings are sensitive to salts in irrigation water, mainly sodium chloride.