BORBOREMA, L. D. A.; http://lattes.cnpq.br/4703195471737000; BORBOREMA, Lucyelly Dâmela Araújo.
Abstract:
To ensure agricultural production with safety, especially in the semi-arid region of Northeastern
Brazil, where there is a shortage of low-salinity water and issues of soil and water salinization
are frequent, the development of technologies enabling the use of brackish water in irrigation
becomes necessary. The use of chitosan is considered an alternative to minimize the deleterious
effects of salinity on plants. The objective of present study was to assess the benefits of
application of chitosan on the growth, physiology, and production components of cowpea
irrigated with brackish water. Treatments were arranged in a completely randomized design, in
a 2 × 5 factorial scheme, with two levels of electrical conductivity of irrigation water – ECw
(0.6 and 4.0 dS m-1) and five concentrations of chitosan (0; 0.25; 0.50; 0.75, and 1.00 g L-1),
with four replicates and three plants per plot. The effects of treatments were evaluated on
physiology (relative water content, electrolyte leakage, photosynthetic pigments and
chlorophyll a fluorescence), growth (length of stem, leaf area, stem diameter, and number of
leaflets) and production components (number of pods per plant, average pod length, number of
grains per pod, grain yield, and grain index). Irrigation with water of electrical conductivity of
4.0 dS m-1 negatively affected the relative water content, electrolyte leakage, growth, synthesis
of photosynthetic pigments, chlorophyll a fluorescence, grain production, and phytomass
accumulation of cowpea cultivar BRS Tapaihum. Nevertheless, the foliar application of
chitosan between concentrations of 0.46 and 0.71 g L-1 mitigated the deleterious effects of
salinity, reducing the electrolyte leakage and increasing the relative water content, number of
leaves, leaf area, synthesis of photosynthetic pigments, photochemical efficiency, grain
production per plant, grain index, and root-shoot ratio. Considering the percentage of
production loss obtained at ECw of 4.0 dS m-1 compared to plants irrigated with water of 0.6
dS m-1, cowpea was classified as sensitive (decrease > 60%) to the salinity of the irrigation
water, with reduction of 72.95%.
