Fertigation with domestic wastewater: Uses and implications

Abstract

The use of wastewater in agriculture is an alternative means of reducing wastewater release into water sources. This process, known as fertigation is an opportunity to make use of organic matter and other nutrients in wastewater for agricultural productivity. The presence of organic matter in these effluents serves as biofertilizer. Since 19th century in Britain, fertigation had been widely accepted due to the scarcity of water, the large amount of sewage produced and the concern about the final destination of wastewater. However, salinization, contamination of soil and agricultural products with the microbial pathogens and presence of heavy metals may limit the use of wastewaters in agricultural system. Thus, the plantation of agronomic varieties that do not have direct use as human food are optional cultivars, which may not have implications of fertigation with domestic wastewater. Fertigation with wastewater will be a nutritive support for the cultivation of Brachiaria brizantha cv Marandu in cerrado soil that is considered as low fertility soil. Soil microorganisms are fertility indicators. For example, nitrogen fixing bacteria (NFB) and arbuscular mycorrhizal fungi (AMF) has great potential to assist in the development of plant varieties under irrigation with domestic wastewater. These microorganisms are good parameters to be used in the analysis of changes that occur when sewage is applied into the soil. Furthermore, microbes contribute to the structuring of the soil, degradation of organic matter and nutrient availability to the biotic component of soil. Despite the limitations of fertigation with domestic sewage, it is a great alternative to use wastewater for nutritional enrichment to the soil that will be used for planting of agricultural crops of commercial interest.

Key words: Brachiaria brizantha, agriculture, salinization, diazotrophic bacteria, mycorrhizal fungi.