Sobrevivência e desenvolvimento de plantas de cajueiro anão em regime de sequeiro com o uso de hidrogel

Abstract

The cashew tree is a plant of great economic importance for the Northeast region of Brazil, the largest national producer of cashew nuts. However, this is a region that suffers from rainfall irregularities, causing high levels of plant mortality, especially in the first year after planting. In the context, the use of soil conditioners is na alternative to reduce losses in the implantation of the orchards and the consequent need for replanting, avoiding the unevenness of the plants. The objective of this research was to verify the effect of the use of hydrogel polymer on the survival and development of dwarf cashew plants, in the first year of orchards, under rainfed regime. The experiment was carried out at the Experimental Field of Pacajus, of Embrapa Tropical Agroindustry, in na orchard implanted with the clone 'BRS 226' in March 2017. The data were collected from March 2017 to May 2018. The treatments were distributed in a rndomized block design in a factorial scheme (5x2). The treatments were doses of hydrogel applied: 0.0L; 0.5L; 1.0L; 1.5L; 2.0L, applied to the bottom of the pit to a depth of 0.5m, or applied to the bottom of the pit made with an articulated hand digger of the "Wolf's mouth" type, at a depth of 0.3m. Plant deaths by treatment ware monitored, taking the days until their occurrence as bare, conducting survival analysis using free software R and constructing survival curves obtained by the Kaplan Meier estimator, and subsequently submitting to the Log-Rank test, for the verification of statistical difference. The height, stem diameter and canopy wingspan data were submitted ANOVA by the AgroEstat software. Development curves were also obtained for the seedling height and stem diameter characteristics. The results allowed greater survival, not showing deaths in the first year after planting and the treatments that received applications in the bottom of the pit survived more days and presented higher percentages of survival. The application of hydrogel had no negative effects on the plant development, none of the evaluated parameters. The results allowed to conclude that the use of hydrogel had a good performance in increasing the survival of dwarf cashew tree plants, not having negative effects on its development.