ABSTRACT Water supply quality, nutrient availability in irrigation solutions, and discharge water or effluents must be monitored for protected cultivation to achieve sustainable management of food production. This study aimed to evaluate whether effluent solution from mini-tomato-protected crops can be recycled in an irrigation system based on plant nutritional demands. The experiment was carried out on a farm with mini-tomato protected-cropping. Water supply, as well as nutrient and effluent solutions, were analyzed in the experiment. Water supply was within the Brazilian limits established by CONAMA, except for nitrite, phosphorus, and sulfide. The effluent solution showed significant concentrations of macro- and micronutrients, highlighting phosphorus (220 to 395 mg L-1). The replacement of nutrient solution in the central fertigation tank, excess of elements applied in the nutrient solution, and accumulation of effluent solution in the disposal tank kept the effluent solution enriched when compared to the nutrient solution initially applied. Water quality monitoring showed that effluent solution can be reused in the irrigation system based on its physicochemical parameters and mini-tomato tomato nutritional demands. The analyses also allowed us to detect control points to achieve food production sustainability.

ABSTRACT Tomato cultivation in a protected environment is an important tool for increasing yield, quality, and regularity of production. However, nutrient imbalance in this production system can lead to short-and long-term losses. This study aimed to characterize plant growth and nutrient accumulation and export of two tomato hybrids of the Salad (‘Stella TY’) and Italian (‘HS 1188’) groups in a protected environment and determine the accumulated thermal sum. The treatments consisted of evaluation times. Dry mass and nutrient accumulation could be determined by a sigmoidal non-linear model for both hybrids grown in the protected environment. The cumulative nutrient order was K > Ca > N > S > Mg > P > Mn > Zn > Fe > Cu > B for ‘Stella TY’ and K > N > Ca > S > P > Mg > Mn > Fe > Zn > Cu > B for ‘HS1188’, with yields of 105.7 and 103.4 t ha−1, respectively. The accumulated thermal sum was 1851.7 degree days at 126 days after transplanting (DAT).