Water scarcity in semiarid regions represents a critical challenge for sustainable agriculture, reducing the availability of forage and affecting livestock systems. The reuse of treated wastewater offers an environmentally friendly alternative to meet water and nutrient needs, supporting the principles of the circular economy. Sweet sorghum, with its remarkable tolerance to abiotic stress, represents a resilient crop option. Evaluating its agronomic and industrial responses to different depths of irrigation using reclaimed water is essential for improving resource-efficient agricultural practices in water-limited environments. This study evaluated the effects of different irrigation regimes with treated wastewater on the growth, productivity, and water use efficiency of sweet sorghum grown in a semiarid region of Brazil. The experiment was conducted in a randomized complete block design, with five irrigation regimes ranging from 50% to 150% of crop evapotranspiration (ETc) and four replications. Irrigation was carried out with treated wastewater using a drip irrigation system. Growth parameters, fresh biomass, water use efficiency, and soluble solids content (°Brix) were analyzed in two consecutive harvests (main and ratoon crop). Deficit irrigation regimes (50% and 75% of ETc) resulted in higher water use efficiency and higher °Brix, whereas regimes above 100% of ETc reduced water use efficiency and biomass productivity. The ratoon crop showed greater sensitivity to water management, with significant productivity responses under irrigation around 100% of ETc. The first harvest was more productive in terms of fresh biomass and plant growth. Reclaimed water is a sustainable and efficient strategy for cultivating sweet sorghum in semiarid regions. Deficit irrigation regimes can be technically viable for maximizing water use efficiency and production quality, while proper irrigation management is crucial to avoiding losses associated with excessive water application.

The reuse of wastewater from domestic sewage can contribute to forage production in regions with limited water availability. The aim was to study the agronomic performance of Gigante, Miúda, and Orelha de Elefante Mexicana cactus pear cultivars irrigated with treated sewage water; contents of macro- and micronutrients in plant tissues; export of nutrients and productivity. The study was conducted in an area near the domestic sewage treatment plant in the municipality of Guanambi, Bahia, Brazil. The experimental design was completely randomized blocks, with six replications. A drip irrigation system was used, with a flow rate of 1.6 L h⁻¹ and a watering interval of three days, applying 33% of the reference evapotranspiration. The physical/chemical characteristics of the soil, dry matter content, nutritional content of the forage cactus pear, productivity, and soil quality were evaluated. Without soil correction or application of mineral or organic fertilizers, only with the application of wastewater, the forage cactus pear plants developed within expected standards. The ‘Orelha de Elefante Mexicana’ and the ‘Gigante’ show greater green mass productivity and irrigation water productivity for green mass when compared to the ‘Miúda’. The highest dry matter productivity is expressed by the Orelha de Elefante Mexicana cultivar. The decreasing order of macronutrient export by the forage cactus pear is K, Ca, N, Mg, S, and P, and Mn, Fe, Zn, B, and Cu for micronutrients. Irrigation with treated wastewater, using 33% of the reference evapotranspiration, maintains K contents within a sufficient range; however, for the other nutrients, it is insufficient for the forage cactus pear plants.

The forage cactus Mexican Elephant Ear is widely incorporated into the animal productive chain of the northeast region of Brazil. However, there is a lack of studies on the physiological dynamics of this cactus. Therefore, this study was conducted at the Estação Experimental Prof. Ignácio Salcedo of the Instituto Nacional do Semiárido (INSA), in Campina Grande, State of Paraíba, Brazil. The aim of this study was to evaluate CO2 uptake and water-use efficiency levels in Opuntia stricta (Haw.) during different seasons and evaluation times. The treatments were distributed using a 24×2 factorial arrangement, which corresponded to the evaluation of gas exchange processes for 24 hours in the rainy (June) and dry (December) seasons. The evaluated parameters were stomatal conductance, transpiration and CO2 uptake rate, internal CO2 concentration, instantaneous water-use efficiency and intrinsic water-use efficiency. The results revealed that gas exchange in the forage cactus was more intense during the rainy season, with good stability, than the low exchange levels during the dry season. Regardless of the season, the CO2 uptake peaked between 24:00 and 02:00. In addition, this range of time is the most suitable to conduct analyses under field conditions.

O Marmeleiro (Croton sp.) e os seus arredores: manejo e oportunidades de utilização na produção florestal / The Croton sp. quince and their surroundings: management and opportunities for use in production forest