EFFECTS OF PHOSPHO-COMPOST AND MUD FROM PHOSPHATE SLUDGES COMBINED OR NOT WITH AN ENDOMYCORRHIZAL INOCULUM ON THE IMPROVEMENT OF THE AGRONOMIC PARAMETERS OF MAIZE (Zea mays L.) PLANTS

To ensure sustainable management of limiting soil P and minimize the extensive use of mineral fertilizers, friendly environmental agricultural practices are required. In this study, the effects of phospho-compost and phosphate sludges either alone or combined with an endomycorrhizal inoculum were tested on the growth parameters of maize plants. Greenhouse pot experiments were carried out to compare the response of maize plants in a soil supplied with five types of amendments. Culture substrate amended with phospho-compost at rate of 5% and mycorrhizal barley roots (10 g) or amended soil at rate 5% of phospho-compost incorporation showed an important increase in both the length of the aerial part and a number of leaves which attained 210 and 195 cm, 14 and 13 leaves / plants respectively. Whereas, the lowest values were noted in agricultural soil and Mamora soil with 90 cm and 11 leaves / plants. The same trend were observed in fresh and dry weights of the aerial and root parts of the maize plants registering respective values of 328.1; 102; 225; and 100.2 g in amended soil with 5% phospho-compost and 10 g of endomycorrhizal inoculum compared to 85.9, 80.9, 46.5 and 35 g in the agricultural soil and Mamora soil respectively. A higher spore number (42 spores / 100 g of soil) and spore content of 66.9% marked the rhizosphere soil of maize plants incorporated with phospho-compost (5%) and endomycorrhizal inoculum (10 g). At the end of pot experiments, maximum mycorrhizal frequency (100%), mycorrhizal intensity (68%) and the vesicular content (20.5%) were recorded in the culture substrate enriched by 5% phospho-compost added to 10 g of endomycorrhizal inoculum. This study showed that the addition of low dose phospho-compost (5%) combined with an endomycorrhizal inoculum to the growing medium has a positive effect on the growth and development of maize plants and on the colonization of the roots by endomycorrhizae.