Application of treated domestic sewage effluent on the quality indicators of an Oxisol cultivated with castor bean

Abstract

In semi-arid regions of developing countries worldwide it is necessary to develop low cost technology methods to acquire new water supplies. The objective was to evaluate the changes in the attributes of soil quality irrigated with treated sewage effluent. The treatments consisted of applying treated sewage effluent (TSE) and underground well water (UWW) in the following proportions: E 0% (chemical fertilization and UWW), E 25% (25% TSE and 75% UWW), E 50% (50% of TSE and UWW), E 75% (75% TSE and 25% UWW) and E 100% (100% TSE). The sodium content did not differ significantly among the treatments, but the sodium input diminished as the percentage of residuary water in the irrigation grew. There was a greater increment of microbial biomass carbon in the E 25% treatment. On the other hand, although treatments E 50% to E 100% have a greater nutrient input, they were no different from control treatments performed with well water. Treated domestic sewage effluent at a proportion of 25% is a feasible alternative for castor bean irrigation, however it is necessary to monitor the possible changes in the soil attributes over successive crops. Microbial attributes can be used as a quick, good indicator of changes in soil quality.

Productivity and nutrition of castor bean fertilized with sewage sludge stabilized by different processes

“…Several studies have been conducted on sewage sludge in agriculture to evaluate its role in alleviating the negative impacts caused by its accumulation and, because of the potential of this residue, as an alternative source of fertilization, to fully or partially supply the nutritional needs of plant species of economic and social interest (Freitas et al, 2015;Fávaris et al, 2016). Studies involving fertilization with sewage sludge have been conducted in Brazil and the results were favourable for several crops in the response obtained to the application of this waste (Nascimento et al, 2015;Santos et al, 2019;Gonçalves et al, 2019).…”