P17: Effect of application of composts on Arbuscular mycorrhizal fungi in beans grow

Arbuscular mycorrhizal fungi (AM) are widely distributed on the earth. As all mutualistic beneficial cooperation, both partners (fungi and plant) have advantages of the symbiosis: carbon from the photosynthesis is used by the fungi and the mycorrhizal plant access phosphorus beyond the depletion zone through the extra radical fungal hyphae; consequently this association improves the plants growth.

In this work we prepared five composts with different quantities of sludge from two wastewater treatment plants: a beverage factory and a paper factory, both non toxic; they were mixture with residues of chili and corn stubble. Mixtures were composted by four months and analyzed the physicochemical parameters C/N relation, organic matter, pH and conductivity. Finally they were added to soil to cultivate beans. Plants in soil with composts growth very well, and their beans production were higher than in control (soil with no addition of compost).  Additionally each month there were taken samples of soil around roots to separate and quantify spores of AM. At the end of the study the number of AM was much higher then spores found in control. The final number of spores by 100 g of soil was: 179 with compost 1; 85 with compost 2; 214 with compost 3; 180 with compost 4; 192 with compost 5; and 47 spores/100 g soil in control, land with no addition of compost. Composts have a beneficial effect over growth of plants, production of fruit and additionally in the association with microorganisms as Arbuscular mycorrhizal fungi.