Interação da salinidade com doses de Ca2+ e K+ para adaptações no cultivo de alface hidropônica em sistema DFT no semiárido brasileiro

Abstract

The use of brackish water in agriculture has been an increasingly common practice in the semi-arid region. More efficient management is used to minimize the effects of salts on plants. The use of genetically improved plants, use of desalination plants, among other practices, are ways to adapt certain crops in this region. Another important practice is plant nutrition that optimizes crops with the ionic balance between nutrients, linked to this is hydroponics, in which it uses plant nutrition to cultivate in less time and more efficiently. The objective of this work was to study the interaction of salinity with different doses of calcium and doses of potassium in the nutrient solution in order to mitigate the effects of salts in hydroponic lettuce cultivation. The work was carried out in a nursery with dimensions of 12mx30m in the Experimental Sector of the State University of Paraíba (UEPB) and in the Laboratory of Plant Production Technologies (LAPROV), located in the municipality of Catolé do Rocha (PB). The experimental design used was DIC, with a 4x2x2 factorial, with four doses of electrical conductivities (1.5; 2.5; 3.5 and 4.5dS/m) two of potassium in the form of potassium nitrate (40g; 50g/100L ) and two doses of calcium in the form of calcium nitrate (60g; 75g/100L) with six replications. Simulated saline waters were used to represent the water from wells in the region. The variables studied were plant height (ALT), total fresh mass (MFT), leaf fresh mass (MFF), root fresh mass (MFR), leaf dry mass (MSF), root dry mass (MSR), number of total leaves (NFT), number of commercial leaves (NFC), leaf area (AF), head diameter (DC), head circumference (CC), root length (CR), root volume (VR), relative water content (CRA), moisture (%UM) and membrane damage (DM). It was possible to verify that the reduction of 20% of calcium nitrate and 20% of potassium nitrate provided the largest plants; and that interaction of Na+/Ca2+ + K+ needs to be further studied, to understand in more detail the chemical balance of these nutrients in the plant.