Consortium of Lettuce and Beet in Succession to Green Manure Irrigated by Treated Dairy Effluent

Green manure as phytoremediation can help with the technical feasibility of growing vegetables irrigated with dairy effluent treated by an anaerobic system (ANE). The objective of this study was to evaluate the production of lettuce cultivated in conjunction with table beet following the irrigation of green manure with treated effluent from a dairy processing plant and its impact on the chemical characteristics of the soil. The experimental design utilized a randomized blocks, factorial scheme, employing two water sources (tap water [TW], dairy effluent treated by an ANE) and four green manures, with four replicates. At the 45-day transplantation (DAT) mark, lettuce plants were analyzed, and at the 73-day DAT, the table beet. Lettuce demonstrated enhanced productivity in succession to pigeon pea, irrespective of water source, with productivity values of 2.28 kg m^-2 for TAP and 2.76 kg m^-2 for ANE. The nutrient supply by the effluent had a positive influence on the production of table beet roots when in succession to jack bean, Crotalaria juncea, and pigeon pea, with values of 3.76, 3.50, and 3.50 kg m^-2, respectively. Furthermore, the cultivation of lettuce and table beet in succession to green manures led to a reduction in sodium levels, resulting in a decrease in the exchangeable sodium percentage of irrigated soil treated with dairy effluent from 4.33% to 1.97%.