Effect of the incorporation of saltgrass (Distichlis spicata (L.) greene) burn residues on phosphorus fixation in an aridisol

The preferred practice for removing the natural growth of saltgrass on the soil, at the start of soil preparation for seed sowing, is the onsite combustion, a fact that introduces a change factor in the chemical properties of the soil at the moment of interaction with the irrigation water. Phosphorus (P) in the soil is one of the limiting macronutrients for the growth and development of plants; it is the element with the greatest availability problems, due to the physico-chemical fixation to which it is subjected as a consequence of the specific adsorption on allophanic minerals. Consequently, we evaluated the effect generated by the incorporation of saltgrass burn plant residue on the pH, electrical conductivity and P fixation capacity in an Aridisol. The burned plant residues were mixed with soil at rates of 0, 5, 15, 25 and 50% (w/w) and these amended soils were mixed with a P solution (100μg·ml^-1) in a ratio of 1:10 (soil:P solution). The addition of saltgrass combustion residues to arid soils leads to a rise of the pH from 7.47 to 8.41, an increase of EC from 14.91 to 103.62mS·cm^-1 and an increment of the phosphorus fixation from 16.6 to 99.9%. It is essential to eliminate this practice of burning in situ given the changes it produces in the soil's physicochemical properties.