MORFOFISIOLOGIA DE MAMOEIRO SOB FREQUÊNCIA DE IRRIGAÇÃO COM ÁGUA SALINA, EM SUBSTRATOS COM HIDROGEL

Abstract

The success of an orchard, in addition to other prerequisites, depends on biological material of good quality, seeds or seedlings and a water with quality for irrigation that may contain saline contents that promote inhibition of seedling growth and loss of the orchard quality. In the search for alternatives to mitigate the effect of salts on the production of seedlings, the aim of this study was to evaluate the effects of the association between saline water and hydroabsorbent polymer in irrigation frequencies and volumes container on the morphophysiological attributes of seedlings of Hawaii papaya cultivar Sunrise Solo. This study was carried out in March and May of 2017, in a protected environment of the Departamento de solos e Engenharia Rural, of the Centro de Ciências Agrárias da Universidade Federal da Paraíba, Areia-PB, using as substratum the material of a Red Yellow Oxy soil. The treatments were obtained on the basis of the matrix Composite Central Box of five doses of the polymer Hydroplan-EB/HyA (0,0; 0,2; 0,6; 1,0 e; 1,2 g dm-3) and five electrical conductivities of irrigation water (0,3; 1,1; 2,7; 4,3 e; 5,0 dS m-1) factorially combined with two irrigation frequencies (daily and alternate), plus two additional treatments (0,75 e 1,30 dm3) to observe the effect of the container volume, obtaining the following factorial scheme: [(22+ 2 . 2 + 1) x 2] + 2. The effects of the sources of variation were studied in the stem diameter at the soil level and height of the seedlings, number of leaves and leaf area, root dry matter, stem leaves and total dry matter of the seedlings, dry biomass ratio Root and shoot; specific leaf area, leaf area ratio and leaf matter ratio; Quality index of Dickson, foliar indexes of chlorophyll a, b, total and relation between the indexes of chlorophyll b/a. Based on the results, daily irrigation stimulated the seedling growth. The increase of the volume of the container provided an increase in the biometric growth variables and in the quality improvement of the papaya seedlings. The increase in the salt content of the irrigation water inhibited the growth and quality of the seedlings, independently of the frequency of irrigation. The hydroabsorbent polymer attenuated the effects of salinity under the chlorophyll indexes, and contributed to the obtaining of the seedlings with size and superior quality.