Produção de mudas de mamoeiro irrigadas com água salina

Abstract

Diante da relevância socioeconômica e alimentar do mamoeiro para a região nordeste, onde naturalmente ocorrem águas com teores elevados de sais, notadamente no Semiárido, objetivou-se avaliar a emergência de plantas e o crescimento de duas cultivares de mamoeiro irrigadas com águas salinas. O experimento foi realizado em casa de vegetação do Centro de Ciências e Tecnologia Agroalimentar, da Universidade Federal de Campina Grande (CCTA-UFCG), Campus Pombal, PB, no período de maio a julho de 2011, usando-se um delineamento experimental de blocos casualizados, com os tratamentos distribuídos em esquema fatorial 4 x 2, constituídos de quatro níveis de salinidade da água (1,2; 2,4; 3,6 e 4,8 dS m-1) além de duas cultivares de mamoeiro (Sunrise Solo e Tainung-1) com três repetições, totalizando vinte e quatro parcelas experimentais. Avaliaram-se a emergência, o crescimento e o acúmulo de matéria seca das mudas. O aumento da salinidade da água de irrigação, mesmo se aplicando uma fração de lixiviação de 20%, elevou o teor de sais no substrato o qual foi superior à salinidade limiar da cultura ocasionando reduções na emergência, no crescimento e no acúmulo de matéria seca, sendo a cultivar Tainung-1 a mais sensível.

Papaya seedlings irrigation with saline water in soil with bovine biofertilizer

“…On the other hand, considering the same treatments, irrigation with saline water content higher than 1.43 and 2.48 dS m -1 inhibited stem growth until 0.93 and 5.51 mm, reflecting 78.2% and 10.6% losses in plant growth irrigated with 4.0 dS m -1 water ( Figure 2B). The observed decreased values are corroborated by Sá et al (2013), who observed that water salinity ranging from 1.2 to 4.8 dS m -1 damaged the diameter of papaya seedlings. This is given by the fact that salt stress leads to reduced net photosynthesis rate and stomatal conductance, consequently diminishing CO2 assimilation rate, compromising plant growth (Fernández-García et al, 2014).…”

“…These results corroborate results found by Silva et al (2008), who observed a reduction both in the number of leaves and in leaf area in guava (Psidium guajava L.) plants subjected to salinity treatments. According to Taiz and Zeiger (2013), in general, when plants are subjected to salt stress, including papaya (Sá et al, 2013), reduced leaf area is displayed as a defense mechanism to losses of gas exchange due to CO2 absorption processes and water transpiration. This mechanism contributes to the gradual adjustment of osmotic salts in plants.…”

“…Under semiarid conditions, due to salinity problems that compromise seedling quality, studies in the formation phase, i.e., initial plant growth, are needed to identify tolerant materials (Sá et al, 2013).…”

“…Growth inhibition and crop productive capacity does not occur when cultivated in soils with a saturation extract electrical conductivity ranging between 3 and 6 dS m -1 (Ayers and Westcot, 1999). However, the effect of salinity on plants may vary among species and even among genotypes of the same species (Ayers and Westcot, 1999;Sá et al, 2013).…”

“…The most compromising effects of salinity on seedling production, specifically papaya, are reflected in inhibiting seed germination viability, generalized reduction of growth, loss of productive capacity and agriculture sustainability (Sá et al, 2013). In addition to these effects, reductions in absorption of some essential nutrients with negative changes in the nutritional aspects of plants are seen (Parés and Basso, 2013).…”