Calcium and magnesium content of onions grown with biochar and phytomass under water restricted condition

Abstract

The objective of this work was to evaluate the calcium and magnesium content of onion using biochar and phytomass under conditions of water restriction. The experiment was carried out in a greenhouse, with treatments in a 3 x 2 x 2 factorial, with three doses of biochar (0, 20 and 40 Mg ha^-1 of thermoelectric ash, in similar properties to biochar); two doses of oat and ryegrass phytomass (0.6 Mg ha^-1 dry mass of straw); with and without water restriction (60 and 90% humidity in the pot capacity); in Nitossolo Bruno, with four replications, in a completely randomized design. The plant was evaluated by the digestion process. The results were made by comparing means of the Tukey test. There was an increase in the calcium content of the leaves, roots and onion bulbs, being the nutrient most absorbed by the plant, with a total amount of 41.57 g/kg^-1. The leaf had significant contents in water restriction and straw. The root showed a significant difference in the incorporation of mulch, with a total of 30.89 g/kg^-1. Mg was the least absorbed nutrient in the plant, with a total concentration of 22.74 g/kg^-1. In the leaf, root and bulb, it had a significant effect on restriction, at 90% CV. Ca in the leaf had significant levels in water restriction and straw. The root had significance with the mulch. Mg was the least absorbed nutrient in the plant, the leaf, root and bulb had a significant effect on water restriction.