The in-situ quantification of turbulent flux and evapotranspiration (ET) is necessary to monitor crop performance in stressful environments. Although cacti can withstand stressful conditions, plant responses and plant–environment interactions remain unclear. Hence, the objective of our study was to investigate the interannual and seasonal behaviour of components of the surface energy balance, environmental conditions, morphophysiological parameters, biomass yield and water relations in a crop of Nopalea cochenillifera in the semi-arid region of Brazil. The data were collected from a micrometeorological tower between 2015 and 2017. The results demonstrate that net radiation was significantly higher during the wet season. Latent heat flux was not significant between the wet season and dry season. During the dry-wet transition season in particular, sensible heat flux was higher than during the other seasons. We observed a large decline in soil heat flux during the wet season. There was no difference in ET during the wet or dry seasons; however, there was a 40% reduction during the dry-wet transition. The wet seasons and wet-dry transition showed the lowest Evaporative Stress Index. The plants showed high cladode water content and biomass during the evaluation period. In conclusion, these findings indicate high rates of growth, high biomass and a high cladode water content and explain the response of the cactus regarding energy partitioning and ET.

Irrigation plays a fundamental role in advancing agricultural frontiers and increasing crop productivity, especially in semi-arid environments, because they exhibit high spatiotemporal rainfall variation. This practice is suggested even for adapted crops, such as forage cactus (Opuntia sp.), sorghum (Sorghum bicolor), and single or intercropping systems. In this study, aimed to evaluate the profitability of using irrigation in a single and intercropping forage cactus-sorghum system in a semi-arid region. The experimental design was in randomized blocks in a 5 × 3 factorial arrangement: five drip irrigation depths (0, 25, 50, 75, and 100% of the reference evapotranspiration - ET0) and three cropping systems (single forage cactus, single sorghum, and intercropping forage cactus-sorghum), with four replicates. The 0% ET0 treatment corresponded to rainfed conditions at a depth of 355 mm. A cycle of forage cactus and two sorghum cultivars (plant and regrowth) was conducted between November 2014 and November 2015. It was verified that the highest costs for implantation of the crop systems in irrigated conditions are due to the acquisition of irrigation and input systems, representing 85.3% of the effective operational cost. The single sorghum and forage cactus-sorghum systems provided the highest fresh matter productivity (62,013.05 and 60,075.36 kg ha-1, respectively). Based on economic indicators, the adoption of irrigation depths (25, 50, 75, and 100% ET0) promoted profits for the systems (single and intercropping) from the second year of implementation.

A instabilidade climática, juntamente com as ações antrópicas mau coordenadas de uso indevido da terra, propiciam acentuada pressão nos sistemas de produção em regiões secas, tendo como consequência a baixa produtividade nas atividades agropecuárias nessas áreas. Assim, a utilização de técnicas agronômicas que melhore as respostas produtivas dessas áreas, afim de contribuir com a resiliência das pequenas fazendas do semiárido brasileiro é de grande relevância. Nesse sentido, objetivou-se com essa revisão, contextualizar a região semiárida do Brasil e apresentar práticas agrícolas que contribuem para a exploração racional das propriedades rurais de forma a maximizar os ganhos produtivos e melhorar a resiliência nesse meio de forma sustentável. Desta forma, conclui-se que várias pesquisas evidenciam as melhorias nos sistemas de produção a partir do manejo integrado de práticas agronômicas, tornando possível o enfrentamento aos impactos climáticos e ambientais, e assim, alterando a capacidade de resiliência das áreas deficitárias.Palavras-chave: consórcio, irrigação, cactos, Nopalea, forragem, Opuntia. An approach on resilient agricultural practices for sustainable maximization of production systems in the Brazilian semi-arid region A B S T R A C TClimatic instability, together with poorly coordinated anthropic actions of improper land use, provides strong pressure on production systems in dry regions, resulting in low productivity in agricultural activities in these areas. Thus, the use of agronomic techniques that improve the productive responses of these areas, in order to contribute to the resilience of small farms in the Brazilian semi-arid region is of great relevance. In this sense, the aim of this review was to contextualize the semi-arid region of Brazil and present agricultural practices that contribute to the rational exploitation of rural properties in order to maximize productivity gains and improve resilience in this environment in a sustainable manner. Thus, it is concluded that several studies show improvements in production systems from the integrated management of agronomic practices, making it possible to face climatic and environmental impacts, and thus, changing the resilience capacity of deficit areas.Keywords: intercropping, irrigation, cacti, Nopalea, forage, Opuntia.* E-mail para correspondência:thieres.silva@ufrpe.br (Silva, T. G. F.).

O sucesso do agronegócio no setor pecuário, depende da oferta de forragem para os animais, especialmente em zonas semiáridas, onde as características climáticas e a baixa disponibilidade de alimento podem dificultar a atividade. Diante disso, o uso de práticas agrícolas que melhorem a resiliência agrícola dos cultivos e possibilitem a oferta de forragem durante todo o ano para os animais torna-se imprescindível. Dentre tais práticas, destacam-se: o uso de espécies adaptadas as condições climáticas, escolha da configuração de cultivo, a densidade de plantio e orientação de cultivo. Nesse contexto, duas culturas que merecem destaque em ambientes quentes e secos são palma forrageira e sorgo forrageiro, ambas apresentam elevada eficiência no uso dos recursos, com produtividade satisfatória, além da existência de trabalhos que evidenciam os benefícios na associação dessas culturas na dieta alimentar dos animais. Dessa forma, na presente revisão, objetivou-se analisar as melhorias produtivas e estruturais das culturas da palma e sorgo sob adoção de práticas de resiliência agrícola. Os achados desta revisão, podem servir como subsídios para o planejamento da produção de forragem, ao tempo em que sugerem que a adoção de práticas adequadas (i.e. irrigação, consorciação, orientação de cultivo e densidade) e suas combinações no sistema de produção permitem um melhor aproveitamento dos recursos naturais e, com isso, maiores acúmulos de biomassa, constituindo-se em fatores determinantes para o êxito na produção.Palavras-chave: configuração de cultivo, densidade e orientação de plantio, Opuntia stricta, Nopalea cochenillifera, Sorghum bicolor. Agricultural resilience in intercropped forage cactus-sorghum cultivation in a semi-arid environment: A review A B S T R A C TThe success of agribusiness in the livestock sector depends on the supply of fodder for animals, especially in semi-arid areas, where climatic characteristics and low food availability can hamper activity. Therefore, the use of agricultural practices that improve the agricultural resilience of crops and make it possible to offer fodder throughout the year for animals becomes essential. Among such practices, the following stand out: the use of species adapted to climatic conditions, choice of cultivation configuration, planting density and cultivation orientation. In this context, two crops that deserve to be highlighted in hot and dry environments are forage cactus and forage sorghum, both have high efficiency in the use of resources, with satisfactory productivity, in addition to the existence of studies that show the benefits in the association of these cultures in the diet animal feed. Thus, in this review, the objective was to analyze the productive and structural improvements of palm and sorghum crops under the adoption of agricultural resilience practices. The findings of this review may serve as inputs for the planning of forage production, while suggesting that the adoption of appropriate practices (i.e. irrigation, intercropping, cultivation and density guidance) and their combinations in the production system allow for a better use of natural resources and, with this, greater accumulations of biomass, constituting determining factors for success in production.Keywords: cultivation setting, density and orientation planting, Opuntia stricta, Nopalea cochenillifera, Sorghum bicolor.

A Revista Ciência Agronômica é voltada para estudos relacionados com as Ciências Rurais e Recursos Naturais