Balance of salts and growth of papaya cultivars irrigated with saline water

Abstract

The papaya crop has great socio-economic expression in the Brazil and is mainly grown in the northeastern region, which is facing serious problems of water shortage, particularly in its qualitative aspect, due to high concentration of salts in water. For best performance of a crop it is necessary to adopt managements strategies, such as the use of tolerant cultivars, thus, aimed to assess the balance of salts in the substrate, growth and partition of biomass of varieties of papaya irrigated with saline water. The experiment was conducted in a randomized complete block design with treatments arranged in a 2 x 4 factorial arrangement , consisting of two cultivars of papaya (Sunrise Solo and Tainung - 01) and four levels of water salinity (1.2, 2.4, 3.6 and 4.8 dS m ^-1) with three replications. The balance of salts in the substrate, growth rate and the dry matter partitioning were evaluated to determine crops' tolerance to salinity in the initial growth phase. The water salinity increased linearly electrical conductivity, sodium absorption ratio and exchangeable sodium percentage of the substrate, and reduced growth and the biomass of varieties of papaya, in which reductions in biomass accumulation followed the order leaves > roots > stem. Salinity reduced the percentage of dry weight of stem and leaves and increased the dry weight of roots.