Water scarcity is a major challenge in northeastern Brazil, where efficient water management strategies are essential for sustainable agriculture. This study aimed to evaluate the performance of melon hybrids in terms of biomass production and nutritional status under varying irrigation levels and mycorrhizal fungi (AMF) inoculation. The experiment was conducted in a greenhouse at the State University of Bahia (Juazeiro, BA, Brazil) using a randomized block design with a 4 × 2 × 4 sub-subdivided plot scheme. The treatments included four irrigation levels (50%, 75%, 100%, and 125% of crop evapotranspiration—ETc), two melon hybrids (Juazeiro and Mandacaru), and four AMF inoculation treatments (non-inoculated with AMF, Entrophospora etunicata, Acaulospora longula, and their combination), with 10 replications. The results indicated that the inoculation with A. longula significantly improved biomass production and plant nutrition, particularly for the Juazeiro hybrid. The most significant improvements were observed in biomass production and nutritional status when this mycobiont was used, highlighting the potential of AMF inoculation as a strategy to enhance water use efficiency and plant tolerance under water-limited conditions. Root colonization in melon plants ranged from 6% to 60%, with an overall average of 36.2%, in Experiment I, and from 6% to 72%, with an average of 40%, in Experiment II. Melon biomass production responded differently to irrigation levels, with Experiment I showing polynomial decreases in biomass as water levels decreased, while Experiment II exhibited linear increases in biomass with higher irrigation, likely influenced by supplementary fertilization. When evaluated, the levels of macronutrients present in the aerial part of the plants did not show significant differences for the treatments concerning the levels of P, K, and Mg, except for Ca. These findings suggest that A. longula is a suitable mycobiont for optimizing melon plant performance in regions with limited water resources, like northeastern Brazil. The study also emphasizes the importance of selecting appropriate Mycorrhizal fungi to maximize symbiotic benefits in melon cultivation under deficit irrigation systems.

In Northeast Brazil, climatic factors and technology synergistically enhance melon productivity and fruit quality. However, the region requires further research on the efficient use of water resources, particularly in determining the crop coefficient (Kc), which comprises the evaporation coefficient (Ke) and the transpiration coefficient (Kcb). Air temperature affects crop growth and development, altering the spectral response and the Kcb. However, the direct influence of air temperature on Kcb and spectral response remains underemphasized. This study employed unmanned aerial vehicle (UAV) with RGB and Red-Green-NIR sensors imagery to extract biophysical parameters for improved water management in melon cultivation in semiarid northern Bahia. Field experiments were conducted during two distinct periods: warm (October–December 2019) and cool (June–August 2020). The ‘Gladial’ and ‘Cantaloupe’ cultivars exhibited higher Kcb values during the warm season (2.753–3.450 and 3.087–3.856, respectively) and lower during the cool season (0.815–0.993 and 1.118–1.317). NDVI-based estimates of Kcb showed strong correlations with field data (r > 0.80), confirming its predictive potential. The results demonstrate that UAV-derived NDVI enables reliable estimation of melon Kcb across seasons, supporting its application for evapotranspiration modeling and precision irrigation in the Brazilian semiarid context.

The objective of this work was to evaluate the behavior of Crisphead lettuce as a function of production seasons under different forms of protected environment. Two experiments were carried out in the field at different times: September to December 2017 and June to August 2018, in a randomizaed blocks desing, in a 4 x 7 factorial scheme, the first one being production environments under shade nets: red screen, chromatinet® screen, black screen and full sun, and the second, lettuce cultivars: Winslow, Irene, Balsamo, Rafaela, Iron Wood, Great Lakes and Delícia. The harvest was carried out at forty-two days after transplanting, where the following variables were analyzed: stem length (cm), total production and commercial productivity (t ha-1). The data were submitted to analysis of variance, and a joint analysis was performed to analyze the treatments effect, then the means were compared by the Scott-Knott test, at 5% probability. The microclimate was altered in the shaded beds, which affected the cultivars development. The cultivation in protected environment provides higher productivity of Crisphead lettuce from September to December, at that time the cultivars Balsamo and Delicia were highlighted under chromatinet®. In the period of mild temperatures, a better performance was observed for cv. Balsamo in full sun.