Saline stress and potassium/calcium ratio in fertigated eggplant

Abstract

In order to evaluate the effect of irrigation water salinity in interaction with different potassium and calcium ratios applied through fertigation in eggplant, an experiment was carried out at the Department of Environmental and Technological Sciences of the Federal Rural University of the Semi-Arid Region, in Mossoró, RN, Brazil. The experimental design was randomized blocks, in a 5 x 4 factorial scheme, with four replicates. The treatments were obtained by the combination between five ionic ratios of potassium and calcium (F1 = 4.2/1; F2 = 3.5/1; F3 = 2.8/1; F4 = 2.2/1; F5 = 1.8/1) and four levels of irrigation water salinity (S1 – 0.5; S2 – 2.0; S3 – 3.5; and S4 – 5.0 dS m-1). The following variables were evaluated: number of fruits per plant, fruit length, fruit diameter, fruit fresh weight and yield. Yield, fruit length, fruit fresh weight and number of fruits decreased with the increase of salinity in all the treatments. Salinity significantly affected fruit diameter, which increased only under fertigation with potassium-rich solutions.

Salinity tolerance of tomato fertigated with different K+/Ca2+ proportions in protected environment

“…These results show that the use of saline water can cause reduction in fruit size, confirming the information presented by other authors (Santos et al, 2016;El-Mogy et al, 2018), as observed in other solanaceous crops, such as eggplant (Santos et al, 2018) and bell pepper (Oliveira et al, 2018;Dias et al, 2019;Santos et al, 2019;Silva et al, 2020).…”

“…These results demonstrate that the fertigation treatments F1, F4 and F5, which applied higher concentrations of either K (F1) or Ca (F4 and F5), were not efficient to mitigate the effect of salinity on NFR, thus being consistent with the result observed by Tuna et al (2007) and Santos et al (2018), when working with hydroponic tomato and eggplant plants, respectively, subjected to salinity and calcium levels in nutrient solution. These authors also found that the increase in calcium concentration did not reduce the effect of salt stress on the number of fruits.…”

“…Some studies have been conducted to evaluate the effect of calcium and potassium nutrition on plants subjected to salt stress, for instance those conducted with bell pepper (Rúbio et al, 2009;Silva et al, 2020) and eggplant (Santos et al, 2018), which showed that the enrichment of the growing medium with potassium and/or calcium may alter the response of plants to salinity. Thus, supplementation of the nutrient solution with potassium and calcium can promote higher tolerance of plants to salinity, as it will promote mutual competition between two ions (Na + and K + /Ca 2+ ) for a transport site (Zhang et al, 2016).…”

Yield of maize crop irrigated with saline waters

“…Salinity is an abiotic stress which limits plant growth and yield worldwide. The excess of salts in many regions of arid and semiarid areas constitutes a serious obstacle for the production system, due to both the changes in soil physical and chemical attributes and the action of specific ions such as Na + and Cl - (Santos et al, 2018).…”

Yield of eggplant using low quality water and pulse drip irrigation

“…According to Medeiros et al (2017), under semiarid conditions, it is possible to produce eggplant using wastewater, minimizing the application of mineral fertilizers. Santos et al (2018), studying salt stress in eggplant, observed that the variables yield, length, fresh mass and number of fruits per plant decreased with the increase in irrigation water salinity.…”