Reuse in the agro-industrial: Irrigation with treated slaughterhouse effluent in grass

Abstract

Abstract The animal slaughter and meat processing industries generate large sources of effluents, rich in organic matter that can be used in plants irrigation as strategy in order to reuse water in agricultural properties. The objective of this work was to evaluate the production and the composition of coastcross grass for hay production by sprinkler irrigation with urea effluent treated by the anaerobic exercise. The experimental was developed in randomized blocks, with five treatments and four replicates (5 × 4), with time subplots. The five treatments used were: (i) T1 - irrigation with surface water plus 50.0 kg ha−1 cut−1 nitrogen fertilization (NF) provided as urea; (ii) T2, T3, T4 and T5 - irrigation with treated slaughterhouse effluent (TSE) plus 0, 16.5, 33.0 and 50 kg ha−1 cut−1 NF. The variables analyzed were the production of fresh and dry mass, soil chemical characteristics and prospective and bromatological analysis, during the winter and the summer. After the treatment, the effluent showed elevated concentration of total nitrogen (176.00 ± 52.32 mg L−1) and a low to moderate saline potential (EC = 1.46 ± 0.34dSm−1). In the winter the nutritional status and the coastcross grass production were kept by irrigation with the effluent, compared with the surface water treatment saving 100% of the nitrogen fertilization. The percentage of phosphorus, sodium and base saturation of the soil were altered by the wastewater. During the summer, the irrigation sludge with effluent were reduced due to rainfall inhalation, with less nutrients support. The higher precipitation occurrency at this season reduced the total amount of salt in the soil. The total production (winter and summer) of dry mass and fresh dough were superiors with the 100% NF treatments, regardless of the water source.