Lady Daiane Costa de Sousa Martins

The seasonality of forage production is one of the main challenges in semi-arid regions, where environmental conditions limit agricultural productivity. One promising option is the use of elephant grass ‘BRS Capiaçu’, together with deficit irrigation. This study evaluated the impact of different irrigation depths with brackish water (50%, 75%, 100% and 125% of the reference evapotranspiration – ET ₀ ) on the productive, physiological, photochemical and biochemical aspects of ‘BRS Capiaçu’ over two cycles. Irrigation with 50% of the ET ₀ resulted in lower rates of net photosynthesis (P _n ), with a reduction in photosystem II quantum yield (ΔF/Fm’), qP, NPQ and the electron transport rate (ETR), in addition to greater activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), indicating oxidative stress. The depths of 50% and 100% of the ET ₀ resulted in greater dry matter production, for Cycles 1 and 2, respectively, demonstrating the resilience of the crop to water stress, attributed to such mechanisms of acclimatisation as a reduction in transpiration (T _r ) and an increase in water use efficiency. These physiological changes were more obvious during Cycle 2, in which the crop was subjected to lower rainfall (47.8 mm), while salt stress was also more pronounced during this period, in response, the plants showed less water loss through transpiration and larger WUE _inst . It was concluded that ‘BRS Capiaçu’ has a high capacity for acclimatisation to semi-arid conditions, and stands out as a viable alternative for mitigating the seasonality of forage production and promoting sustainable livestock farming in the region.

The growing demand for sustainable livestock systems requires efficient methods for monitoring forage biomass. This study evaluated spectral (RGB and multispectral), textural (GLCM), and area attributes derived from unmanned aerial vehicle (UAV) imagery to predict buffelgrass (Cenchrus ciliaris L.) biomass, also testing the effect of soil pixel removal. A comprehensive machine learning pipeline (12 algorithms and 6 feature selection methods) was applied to 14 data combinations. Our results demonstrated that soil removal consistently improved the performance of the applied models. Multispectral (MSI) sensors were the most robust individually, whereas textural (GLCM) attributes did not contribute significantly. Although the MSI and RGB data combination proved complementary, the model with the highest accuracy was obtained with CatBoost using only RGB information after Boruta feature selection, achieving a CCC of 0.83, RMSE of 0.214 kg, and R² of 0.81 in the test set. The most important variable was vegetation cover area (19.94%), surpassing spectral indices. We conclude that integrating RGB UAVs with robust processing can generate accessible and effective tools for forage monitoring. This approach can support pasture management by optimizing stocking rates, enhancing natural resource efficiency, and supporting data-driven decisions in precision silvopastoral systems.

Agriculture in semi-arid regions faces challenges, such as water scarcity and low soil fertility, making the forage cactus a highly important crop due to its crassulacean acid metabolism (CAM) pathway. The productivity of the forage cactus, however, depends on proper water and nutrient management, especially nitrogen. Despite its importance, there is little research into the effects of nitrogen fertilisation on productive, photochemical, physiological and biochemical parameters, or on intercropping systems. Increasing doses of nitrogen are assumed to enhance CAM pathway, improving productivity, gas exchange, photochemical efficiency and antioxidant accumulation, in addition to mitigating the effects of oxidative stress under adverse conditions. The experiment was conducted in Serra Talhada, Pernambuco, Brazil, in a randomised block design with four replications. Changes in the biometric, productive, photochemical, physiological and biochemical parameters were evaluated in forage cactus intercropped with sorghum (Sorghum bicolor) or pigeon pea (Cajanus cajan) subjected to different doses of nitrogen (0, 75, 150, 300 and 450 kg ha⁻¹). The results showed that nitrogen fertilisation promoted a higher photosynthetic rate and greater stomatal conductance, increased transpiration, and higher levels of pigment and soluble proteins, in addition to reducing lipid peroxidation. Our findings revealed that the cactus—pigeon pea intercropping system has better photosynthetic, enzymatic and productive performance at a dose of 150 kg N ha⁻¹, whereas the cactus—sorghum intercropping system required 450 kg N ha⁻¹ to achieve similar results. Overall, proper nitrogen management in intercropping systems can optimise the physiological performance and productivity of the forage cactus in semi-arid environments.

Floriculture is one of the most promising segments of global agribusiness, characterized by high profitability and continuous expansion, especially in countries such as the Netherlands, China, and the United States. In Brazil, the sector has stood out for its steady growth, even in the face of economic and climatic adversities, generating billions of reais and thousands of direct and indirect jobs. Among the species of greatest commercial relevance, amaryllis (Hippeastrum hybridum Hort.) presents significant economic and ornamental potential due to its wide diversity of cultivars, high market demand, and good adaptability to tropical and subtropical conditions. However, environmental factors, particularly water availability, significantly affect the productivity and quality of this species’ flowers and bulbs. Water stress induces physiological and biochemical changes, such as stomatal closure, reduced photosynthetic rate, and accumulation of reactive oxygen species, compromising cellular metabolism and the visual appearance of the plants. To minimize these effects, amaryllis exhibits adaptive responses associated with increased activity of antioxidant enzymes and structural modifications in leaf tissues. This review presents an updated overview of the flower agribusiness, emphasizing the economic importance and edaphoclimatic requirements of amaryllis, and discusses the main physiological mechanisms involved in the response to water deficit. Understanding these responses is essential for the development of more efficient and sustainable water management practices, contributing to the production of higher-quality flowers and to strengthening the competitive performance of Brazilian floriculture.

The semi-arid environment is characterized by adverse edaphoclimatic conditions, such as low and irregular rainfall, high evapotranspiration, and low-fertility soils, imposing severe limitations on agricultural and livestock production. In this context, adaptive strategies for water management and the use of forage species adapted to these conditions become essential to ensure productivity and sustainability. This review aims to analyze and discuss the relationship between water indices, evapotranspiration, and water management strategies—including irrigation with brackish water (biosaline agriculture)—in the sustainable production of the BRS Capiaçu cultivar under semi-arid conditions. The study addresses the characterization of the semi-arid region and its limitations, the main morphological and productive characteristics of BRS Capiaçu, and the relevance of water management in mitigating water stress. Drip irrigation is highlighted as an efficient technique for the rational use of water, and biosaline agriculture as a promising alternative in the face of scarce good-quality water resources. In addition, the concepts of evapotranspiration and water use efficiency (WUE) are discussed as essential parameters for irrigation planning and management. It is concluded that the combination of adapted genetic materials, water management practices, and the use of brackish water constitutes a sustainable strategy to increase forage production and ensure the economic and environmental viability of livestock farming in the Brazilian semi-arid region, emphasizing the importance of BRS Capiaçu as a high-yield and drought-resilient alternative.

The forage cactus (Opuntia spp.) stands out as a strategic crop for semiarid regions due to its high water-use efficiency and resistance to water stress and intense solar radiation. In addition to its fundamental role in animal feeding, this species shows great potential for the utilization of bioactive compounds with industrial applications. Among these compounds, the mucilage extracted from the cladodes has attracted increasing scientific and technological interest. It is a natural, biodegradable, and biocompatible polysaccharide, whose physicochemical properties provide it with high water retention capacity, viscosity, and the ability to form films and gels. These characteristics make cactus mucilage a promising alternative for the production of biodegradable packaging and edible coatings, especially in the post-harvest preservation of fruits and vegetables, contributing to loss reduction and extended shelf life. Beyond reducing dependence on synthetic polymers, its use adds value to the cactus crop and promotes the development of the regional bioeconomy, with a positive impact on environmental sustainability and food security. However, the advancement of its large-scale application depends on further studies aimed at standardizing extraction methods, chemically characterizing the compound under different edaphoclimatic conditions, and evaluating its performance in cultivation systems. Thus, the full utilization of forage cactus, especially its mucilage, represents a concrete opportunity for technological innovation and the valorization of natural resources adapted to semiarid environments.

Cacti of the genera Opuntia and Nopalea exhibit morphophysiological and biochemical characteristics that favor their adaptation to semiarid environments, such as crassulacean acid metabolism (CAM) and cladode succulence. These strategies reduce water loss and allow the maintenance of photosynthesis under stress conditions. In this study, we evaluated the seasonal variation in the physiological and photochemical responses of forage cactus clones grown in semiarid environments, considering the rainy, dry, and transition seasons. The net photosynthetic rate (P_n) and chlorophyll fluorescence parameters varied significantly as a function of water availability and microclimatic conditions. We found higher CO₂ assimilation rates during the rainy season, while the dry season resulted in a strong impairment of photosynthetic activity, with reductions of 65% in stomatal conductance, 37% in transpiration, 20% in maximum quantum efficiency of photosystem II, and 19% in the electron transport rate. Furthermore, during these periods, we observed an increase in initial fluorescence and non-photochemical dissipation, demonstrating the activation of photoprotective mechanisms against excess light energy. During the transition seasons, the cacti exhibited rapid adjustments in gas exchange and energy dissipation, indicating the adaptive plasticity of CAM pathway. The MIU (Nopalea cochenillifera (L.) Salm-Dyck), OEM (Opuntia stricta (Haw.) Haw.), and IPA (Nopalea cochenillifera (L.) Salm-Dyck) clones demonstrated greater resilience, maintaining greater stability in P_n, instantaneous water use efficiency, and photochemical parameters during the drought. In contrast, the OEA (Opuntia undulata Griffiths) clone showed high sensitivity to water and heat stress, with marked reductions in physiological and photochemical performance. In summary, the photosynthetic efficiency and chlorophyll fluorescence of CAM plants result from the interaction between water availability, air temperature, radiation, and genotypic traits. This study provides a new scientific basis for exploring the effects of environmental conditions on the carbon and biochemical metabolism of cacti grown in a semiarid environment.

The advance of the soil desertification process and water salinisation hinders reforestation actions in the Brazilian semiarid region due to the negative effects on the initial establishment of seedlings. Knowledge of potential species for overcoming the problems of soil and water salinity is of broad interest. This study evaluated the growth of seedlings of the species Handroanthus impetiginosus and Handroanthus spongiosus subjected to the combined stresses of salinity and water deficit. The species were subjected to three water depths (WDs): WD1—50%, WD2—75% and WD3—100% of reference evapotranspiration, and four salinity levels (SL): SL1—0.27 dS m⁻¹, SL2—2.52 dS m⁻¹, SL3—6.35 dS m⁻¹ and SL4—7.38 dS m⁻¹. Biometric data, including plant height, number of leaves, collar diameter and biomass, was obtained. The results showed that H. impetiginosus was more tolerant of the conditions analysed. The species showed greater sensitivity to salt stress, which reduced growth and dry biomass accumulation by up to 98%. Increased water deficit reduced height, collar diameter, number of leaves, root biomass and total biomass. We propose that the optimal water depth for both species is 100% of the reference evapotranspiration.

O semiárido brasileiro tem passado por extensos processos de degradação ambiental, principalmente devido a impactos causados pela atividade agropecuária, desmatamentos e queimadas, apresentando como seu bioma predominante, a Caatinga, o qual possui cerca de 50% da sua paisagem original modificada. O uso de sistemas agroflorestais (SAFs) tem sido abordando na literatura destacando-se como uma forma de exploração sustentável, adotados em diversas regiões ao redor do globo, contudo no semiárido brasileiro, apesar do crescimento de áreas destinadas aos SAFs ter ocorrido no Brasil nos últimos anos, adoção desses sistemas na região semiárida ainda é pouco difundida. Considerando-se os benefícios da adoção dos SAFs onde se destacam a assimilação de carbono e nitrogênio, conservação do solo, redistribuição hidráulica, ciclagem de nutrientes e biodiversidade, e a importância da preservação de áreas do semiárido brasileiro e garantia de segurança alimentar dos produtores, e assim a abordagem econômica e ecológica dos sistemas agroflorestais, objetivou-se com essa revisão enriquecer as discussões sobre esses sistemas, seus benefícios e sua viabilidade, como forma de produção agrícola sustentável e fonte de renda a ser adotada no semiárido brasileiro.

With the growing demand for efficient solutions to face the challenges posed by population growth and climate change, the use of unmanned aerial vehicles (UAVs) emerges as a promising solution for monitoring biophysical and physiological parameters in forage crops due to their ability to collect high-frequency and high-resolution data. This review addresses the main applications of UAVs in monitoring forage crop characteristics, in addition to evaluating advanced data processing techniques, including machine learning, to optimize the efficiency and sustainability of agricultural production systems. In this paper, the Scopus and Web of Science databases were used to identify the applications of UAVs in forage assessment. Based on inclusion and exclusion criteria, the search resulted in 590 articles, of which 463 were filtered for duplicates and 238 were selected after screening. An analysis of the data revealed an annual growth rate of 35.50% in the production of articles, evidencing the growing interest in the theme. In addition to 1086 authors, 93 journals and 4740 citations were reviewed. Finally, our results contribute to the scientific community by consolidating information on the use of UAVs in precision farming, offering a solid basis for future research and practical applications.