Vegetative development and content of calcium, potassium, and sodium in watermelon under salinity stress on organic substrates

Eugênio Gonçalves Da Silva Júnior,Josemir Moura Maia,Jucelino De Sousa Lima,Maria De Fátima Caetano Da Silva,Anselmo Ferreira Da Silva

doi:10.1590/s0100-204x2017001200003

Eugênio Gonçalves Da Silva Júnior, Josemir Moura Maia + Show 3 more

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https://doi.org/10.1590/s0100-204x2017001200003

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Abstract

Abstract: The objective of this work was to evaluate the vegetative development and determine the concentration of sodium, potassium, and calcium in watermelon (Citrullus lanatus) grown on two organic substrates and under increasing saline concentrations. The substrates were soil + earthworm humus (S1) and soil + bovine manure (S2), and the saline treatments consisted of irrigation water with different electrical conductivities: 1.36 (control), 3.56, 5.76, and 7.96 dS m-1. The experimental design used was a randomized complete block in a 2×4 (substrate × conductivity) factorial arrangement with five replicates. Main branch length, root length, stem diameter, leaf number, leaf area, and fresh matter mass of shoots and roots, as well as the sodium, potassium, and calcium contents in the plants, were determined. All phenological parameters showed interaction with the substrates, and S1 improved plant performance. Substrates interacted significantly with: leaf area; leaf number; stem diameter; main branch length; root length; fresh matter mass of shoots and roots; and the contents of sodium, potassium, and calcium, in both shoots and roots of watermelon irrigated with saline water for up to 27 days after emergence. There are also interactions between substrates and salinity for stem diameter, main branch length, fresh matter mass of roots, and calcium contents in both shoots and roots, and potassium and sodium contents in the roots.

Highlights

Fruits and vegetable producers seek to increase production using alternatives that reduce costs
The objective of this work was to evaluate the vegetative development and to determine the concentration of Na+, K+, and Ca2+ in watermelon grown on two organic substrates and under increasing saline concentrations
For the formulation of substrates used in this experiment, bovine manure, earthworm humus, and soil classified as a fluvial Entisol with a sandy loam texture were used, which were subjected to chemical analysis (Table 1)

Summary

Introduction

Fruits and vegetable producers seek to increase production using alternatives that reduce costs. One of them is the use of substrates composed of organic fertilizers during the initial stage of plant development (Góes et al, 2011; Trani et al, 2013). Organic fertilization presents other advantages, such as improvements to quality, soil aeration, and water drainage (Trani et al, 2013). In semiarid regions, poor quality water and degraded soils due to low rainfall and high insolation are often found. These conditions lead to excess salt in irrigation water, which can drastically affect the phenological development and yield of some crops, such as Cucurbitaceae (Farias et al, 2009; Lima Júnior, 2010; Medeiros et al, 2012; Silva Neto et al, 2012)

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