Abstract

Fertigation of agricultural crops that are not directly used in human food, with domestic wastewater is a viable alternative for the sustainable use of water resources. The development of agricultural practices that provide high productivity with the sustainability of agroecosystems has been a great challenge. Thus, our aims were to use of domestic wastewater in the planting of Brachiaria brizantha cv Marandu, as an alternative for animal feed production in Cerrado soils, and to study the physical-chemical and microbiological impacts of the fertigation. These impacts were evaluated, respectively, by physical-chemical indicators content and diversity of nitrogen fixing bacteria (NFB) and arbuscular mycorrhizal fungi (AMF) in the DGGE profile. The NPK contents of the wastewater were used to determine the five fertigation managements (M1 to M5). M1 and M2 managements had no wastewater and M3 to M5 contained 20, 40 and 60% of NPK from the wastewater. The managements in a completely randomized design with 20 plots and 4 replicates were distributed. Soil samplings prior to fertigation and at the end of the experiment were performed. Leaf biomass productivity was determined in three different grass cuts. After fertigation, changes in physical-chemical indicators and in the viable microbial cells counts were observed. The NPK of wastewater increased the abundance of NFBs and AMFs. Leaf biomass productivity per hectare was directly proportional to NPK concentration. In addition, wastewater did not alter the nutritional composition of Marandu grass. Therefore, the fertigation with domestic wastewater showed to be a viable and promising alternative for reuse of this water in Cerrado soil for animal feed production.

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