Efecto de la aplicación de agroquímicos y la inoculación de una bacteria solubilizadora de fosfato sbre el nivel de colonización de hongos micorricicos arbusculares y el desarrollo de plantas de maní y trigo en un sistema de rotación.

FERNÁNDEZ VALDÉS P, DALMASSO RY, ANZUAY MS, LUDUEÑA LM, TAURIAN T, ANGELINI J.

Los Cocos

Congreso; XVIII SAMIGE; 2022

Arbuscular mycorrhizal fungi (AMF) constitute the most common type of symbiosis in nature. AMF colonize the roots of plants without causing harm, and through this intimate contact, the AMF receives carbon fixed by the plant, in exchange for water and mineral nutrients, leading to a positive impact on plant growth. Agricultural ecosystems are dominated by this symbiosis, and agricultural practices can have varying effects on these fungi. The addition of pesticides can alter the fungal biomass and their ability to provide nutrients to their host plant. Considering the importance of phosphorus (P) on plant nutrition and its limited availability in soils, phosphate solubilizing bacteria (BSP) constitute one of the most important bacterial groups in agricultural soils. It has been proven that some BSP can stimulate the establishment and growth of AMF. The objective of this work was to study the impact of the application of agrochemicals used on peanut (Arachis hypogaea L.) and wheat (Triticum aestivum) cultivation and the inoculation of the BSP Enterobacter sp. J49, on the ability of native AMF to colonize roots and on the development of these plants, in a crop rotation system in a microcosm scale. For this purpose, 8 treatments with 5 repetitions each where established: control pots without agrochemicals and non-inoculated seeds; pots without agrochemicals and inoculated seeds; pots with agrochemicals (commercial dose, half dose and double dose) and non-inoculates seeds; and pots with agrochemicals (commercial dose, half dose and double dose) and inoculated seeds. The level of AMF root colonization was determined as the number of root segments colonized divided by the total number of root segments, expressed as percentage, at 40 and 100 days post-sowing. As growth parameters for both plants shoot length, fresh weight, dry weight and P content where measured. Result obtained indicate that on both plants at both times measured the percentage of root colonization by AMF was significantly higher in plants inoculated with the BSP and not treated with agrochemicals, with respect to all non-inoculated treatments. This parameter showed similar results in non-inoculated plants treated with agrochemicals and control plants. When all inoculated treatments where compared, plants treated with double dose of agrochemicals showed the lowest percentage of AMF root colonization. In terms of growth parameters of peanut and wheat at both times, results show that all inoculated plants had significantly higher values than non-inoculated plants. These results show that the addition of agrochemicals at commercial or half-dose has no negative effect on the ability of native AMF to colonize peanut and wheat plants, while the addition of double-dose of agrochemicals has a negative effect on this parameter. In regards to the inoculation of the BSP, our findings confirm the ability of Enterobacter sp. J49 to promote the growth of both plants at both time points measured.