Juliane Rafaele Alves Barros

Cowpea ( Vigna unguiculata (L.) Walp.) is a crop of major importance in semiarid regions, where powdery mildew can significantly reduce productivity. This study evaluated powdery mildew severity in four cowpea cultivars grown under monocropping and intercropping with two biomass sorghum ( Sorghum bicolor (L.) Moench) across two planting seasons (June and December 2021) under semiarid conditions. The experiment was conducted in a randomized complete block design arranged in a 12 × 2 factorial scheme with three replications, and disease severity was assessed at the R9 stage by means of the percentage of leaf area affected. Planting season significantly affected disease severity, and a significant season × treatment interaction was detected, indicating that the effects of cultivar and cropping system depended on planting season. Disease severity was higher in the June planting, whereas December planting reduced severity by 69.60%. Intercropping reduced disease severity for most cultivars during the June planting. Monocropping systems showed higher grain yield due to greater plant density, averaging 2.11 and 2.29 t ha ^{− 1} in June and December planting, respectively, while intercropping averaged 1.15 and 1.22 t ha ^{− 1} . However, intercropped cowpea maintained stable productivity per plant despite a 50% reduction in plant density. These results demonstrate that adjusting planting date and adopting intercropping with adapted cultivars can simultaneously reduce powdery mildew severity and maintain productive stability in semiarid cowpea systems.

The impact of climate on sorghum cultivation, generated mainly by scenarios of increased temperature, can affect plant development and cause losses in crop yield. Thus, the objective of this work was to select sorghum cultivars tolerant to high temperatures, through the evaluation of biometric, enzymatic, and productive parameters. The experiment was carried out in growth chambers, with seven sorghum cultivars (AGRI-002E, BRS 506, BRS 716, SF 15, IAC Santa Elisa, BRS Ponta Negra, and Volumax) and four temperature regimes (20.0-26, 0-33.0°C; 24.8-30.8-37.8°C; 26.3-32.3-39.3°C and 27.8-33.8-40.8°C), in a completely randomized design, with four replications. The biometric and productive parameters and activity of the enzymes superoxide dismutase, catalase, and ascorbate peroxidase were evaluated. The cultivars AGRI-002E, BRS 506, BRS Ponta Negra, and Volumax showed better defense of the antioxidant system with increasing air temperature, with less accumulation of reactive oxygen species and greater biomass production. These cultivars can be classified as tolerant to an increase of up to 6.3 °C in air temperature, with emphasis on cultivar BRS 506, which showed higher production of stem dry mass.

The Cerrado is Brazil’s second largest biome, covering continuous areas in several states. Covering approximately 23% of Brazil’s territory, the Cerrado biome connects with all the main biomes in South America, thus forming a major biological corridor. This biome is one of those that has suffered the most from the incidence of wildfires, leading to a progressive depletion of the region’s natural resources. The aim of this study was to evaluate the use of an Unmanned Aerial Vehicle (UAV) embedded with an RGB sensor to obtain high-resolution digital products that can be used to identify areas of the Brazilian Cerrado affected by wildfires. The study was carried out in a savannah biome area selecting a vegetation corridor with native vegetation free from anthropogenic influence. The following UAV surveys were carried out before and after a burning event. Once the orthomosaics of the area were available, the GLI, VARI, ExG and NGRDI vegetation indices were used to analyze the vegetation. The data indicate that the B band and the GLI and ExG indices are more suitable for environmental impact analysis in Cerrado areas affected by fires, providing a solid basis for environmental monitoring and management in scenarios of fire disturbance.

O objetivo deste estudo foi avaliar a qualidade de produtos digitais obtidos em levantamentos topográficos com aeronave remotamente pilotada para fins de georreferenciamento de imóveis rurais. O estudo foi realizado no Instituto Federal de Educação, Ciência e Tecnologia do Maranhão, Campus São Raimundo das Mangabeiras. Foram selecionadas três áreas com diferentes declividades no terreno: 0 a 5%, 5 a 10% e 10 a 20%. Em cada área foram realizados levantamentos geodésicos com GNSS e aerofotogramétrico com aeronave remotamente pilotada (em três alturas de voo: 70, 80 e 90 m) para coletar as coordenadas de pontos topográficos foto identificáveis, totalizando nove combinações de declividade e altura de voo. O processamento digital das imagens foi realizado tendo como base a técnica Structure from motion, tendo como produto final o ortomosaico e o modelos digital de elevação de cada área/altura de voo. As imagens confeccionadas foram avaliadas conforme os critérios estabelecidos pela Norma Técnica ABNT NBR 13.133/2021 e pelo Manual Técnico para o Georreferenciamento de Imóveis Rurais – 2ª Edição. Foi possível obter produtos digitais com alta precisão posicional planialtimétrica quando comparada a trabalhos similares encontrados na literatura. Pode-se concluir que a altura de voo deve ser configurada de acordo com a declividade do terreno a ser mapeado. Em áreas com maior declividade recomenda-se que os voos sejam realizados em alturas menores para garantir uma maior precisão planialtimétrica dos ortomosaicos e dos modelos digitais de elevação.

Selecting genotypes tolerant to high temperatures is an important measure for agricultural maintenance and production in climate change scenarios. Thus, this study aimed to select cowpea genotypes tolerant to increased air temperature. A total of 20 cowpea genotypes were used, cultivated under temperature regimes of 20–26–33 °C and 24.8–30.8–37.8 °C in a completely randomized experimental design under a 2 × 20 factorial scheme (temperature regimes × genotypes). The BRS Inhuma, Bico-de-Ouro-17-45, BRS Guariba, and BRS Imponente genotypes did not show significant differences in the analyzed physiological responses to the increase in air temperature. The BRS Inhuma, Bico-de-Oouro-17-19, Bico-de-Ouro-17-44, Bico-de-Ouro-17-45, BRS Guariba, and BRS Imponente genotypes showed increased temperature tolerance as thermal stress did not affect production. The Pingo-de-Ouro-17-48, MNC00-595F-27, MNC06-895E-1, and MNC09-981B-2 genotypes reduced water efficiency by −26.85, −25.19, −40.04, and −60.37%, respectively, due to the increase in temperature. The results obtained in this work represent a pre-selection of genotypes that are tolerant to high temperatures, with the BRS Inhuma, Bico-de-Ouro-17-45, BRS Guariba, and BRS Imponente genotypes indicated as tolerant to increased temperatures based on the interaction of physiological and productive responses. There is an urgent need to select cowpea genotypes tolerant to increased temperature to maintain production in climate change scenarios and ensure agricultural systems’ sustainability and food security.

Global projections indicate that the demand for fresh water, energy, and food will increase significantly in the coming decades under the pressure of population growth, economic development, climate change, and other factors. Faced with this, technologies that promote sustainable development through the use of clean energy will be imperative. That way, this study aimed at evaluating the productive performance of biomass sorghum and cowpea cultivars in different cropping systems and planting seasons. The experiment was conducted at the Caatinga Experimental Field at Embrapa Semiarid, Petrolina—PE. Four cowpea (BRS Itaim, BRS Gurguéia, BRS Guariba, and BRS Carijó) and two biomass sorghum cultivars (BRS 716 and AGRI-002E) were used in intercropping and monoculture systems. The cultivars were sown during two different seasons: June (season 1—winter) and December (season 2—summer) of 2021. The biometric and productive parameters and land equivalent ratios (LERs) of sorghum and cowpea were evaluated. The data were subjected to multivariate analysis. The productive performance of biomass sorghum cultivars Agri-002E and BRS 716 was higher when planted in December, with an increase of 37% due to the planting season. Cowpea productivity was not influenced by sowing seasons or the cultivation system. Based on the calculation of efficient land use, the intercropping between biomass sorghum cultivar BRS 716 and cowpea cultivars BRS Gurguéia, BRS Guariba, and BRS Carijó was advantageous when compared to monocultures planted in the hottest season. This study showed the importance of cultivar selection, the planting time, and land use efficiency in intercropping systems.

Plant yield is directly affected by the increase in air temperature and the water availability in the soil. Therefore, the objective with this study was to evaluate the physiological and productive performance of sorghum cultivars as a function of soil water availability and temperature at the cultivation time. The research was carried out at Embrapa Semi-Arid, municipality of Petrolina, Pernambuco state, Northeast region, Brazil, with planting in June 2021 and January 2022. The experiment was conducted in a randomized block design with a 2 × 6 × 4 factorial arrangement, with two growing seasons (season 1: planting in June; season 2: planting in January), six sorghum cultivars (AGRI002E, BRS 716, BRS 506, SF 15, IAC Santa Elisa and BRS Ponta Negra) and four water availability levels (25, 50, 75, and 100%), with four replications. The following variables were evaluated: total dry mass, water use efficiency, photosynthesis, stomatal conductance, transpiration and leaf temperature. The SF 15 and BRS Ponta Negra cultivars produced the highest amount of total dry mass when planted in June, with maximum temperatures ranging from 26 to 34 ºC and 100% water availability. The AGRI002E cultivar showed higher dry mass production, photosynthesis, stomatal conductance and leaf transpiration rates among the other cultivars in season 2, with 100% of soil water retention capacity, demonstrating adaptation to the increase in temperature. O rendimento das plantas é afetado diretamente pelo aumento da temperatura do ar e pela disponibilidade de água no solo. Diante disso, objetivou-se avaliar o desempenho fisiológico e produtivo de cultivares de sorgo em função da disponibilidade de água no solo e da temperatura da época de cultivo. A pesquisa foi realizada na Embrapa Semiárido, localizada no município de Petrolina, Pernambuco, região Nordeste, Brasil, com plantio em junho de 2021 e janeiro de 2022. O experimento foi conduzido com delineamento experimental em blocos casualizados, em arranjo fatorial 2 × 6 × 4, sendo duas épocas de cultivo (Época 1: plantio em junho; Época 2: plantio em janeiro), seis cultivares de sorgo (AGRI002E, BRS 716, BRS 506, SF 15, IAC Santa Elisa e BRS Ponta Negra) e quatro níveis de disponibilidade hídrica (25, 50, 75 e 100 %), com quatro repetições. Foram avaliadas: a massa seca total, a eficiência no uso da água, a fotossíntese, a condutância estomática, a transpiração e a temperatura foliar. As cultivares SF 15 e BRS Ponta Negra produziram maior quantidade de massa seca quando plantadas em junho, com temperaturas máximas variando de 26 a 34 ºC e 100 % de disponibilidade hídrica. A cultivar AGRI002E apresentou maior produção de massa seca, taxa de fotossíntese, condutância estomática e transpiração foliar na época com as temperaturas mais altas, com 100% da capacidade de retenção de água do solo, demonstrando adaptação ao aumento da temperatura.

A utilização de água com altos teores de sais pode causar desequilíbrio nutricional e redução na produtividade das culturas. Nesse contexto, o objetivo do trabalho foi avaliar a extração de nutrientes de três variedades de sorgo forrageiro cultivadas sob diferentes lâminas de irrigação com efluente salino da piscicultura. O experimento foi conduzido em condições de campo, sendo os tratamentos provenientes de um esquema fatorial 3x4, com três variedades de sorgo forrageiro (Volumax, F305 e Sudão) e quatro frações de lixiviação (0; 5; 10 e 15%), dispostos em parcelas subdivididas com quatro blocos. As parcelas foram compostas pelas frações de lixiviação e as subparcelas pelas variedades. Aos 93 dias após o plantio, foram coletadas 10 plantas para a determinação da produção de matéria seca e dos teores de N, P, K, Ca, Mg, Na, Fe, Cu, Zn e Mn. Foram avaliados os totais extraídos e a distribuição dos nutrientes na planta. A variedade F305 extraiu quantidades intermediárias de nutrientes em relação às demais, sendo a variedade Sudão a que apresentou uma maior extração. O uso de fração de lixiviação influencia a quantidade de nutrientes extraídos, alterando sua distribuição nas diferentes partes da planta de sorgo forrageiro. Palavras-chave: Sorghum bicolor Moench; acúmulo de minerais; reuso de água; salinidade. Nutrient extraction by forage sorghum varieties irrigated with saline fish farming effluent The use of water with high levels of salts may cause nutritional imbalance and reduction in crop productivity. In this context, the objective of the work was to evaluate the nutrient extraction of three varieties of forage sorghum cultivated under different irrigation slopes with saline effluent from pisciculture. The experiment was conducted under field conditions, and the treatments came from a 3x4 factorial scheme, with three varieties of forage sorghum (Volumax, F305 and Sudan) and four leaching fractions (0; 5; 10 and 15%), arranged in subdivided plots with four blocks. The plots were composed by the leaching fractions and the subplots by the varieties. At 93 days after planting, 10 plants were collected to determine dry matter production and N, P, K, Ca, Mg, Na, Fe, Cu, Zn, and Mn contents. The total extracted and the distribution of nutrients in the plant were evaluated. The F305 variety extracted intermediate amounts of nutrients in relation to the others, being the Sudão variety the one that presented the greatest extraction. The use of leaching fraction influences the amount of nutrients extracted, altering their distribution in the different parts of the forage sorghum plant. Keywords: Sorghum bicolor Moench; minerals accumulation; water reuse; salinity.

Rising temperature affects agricultural production, causing food insecurity. Thus, the objective of this study was to evaluate how increased temperature influences pollen viability, photosynthetic and enzymatic responses, and their consequences on the final yield of cowpea cultivars. The cultivars BRS Acauã, BRS Guariba, BRS Gurguéia, and BRS Pajeú were used, kept in growth chambers under two temperature regimes: 24.8–30.8–37.8 °C and 20–26–33 °C. The cultivars BRS Acauã, BRS Guariba, and BRS Pajeú showed prolonged flowering and greater flower abortion, at 23.58%, 34.71%, and 25.55%, respectively, under an increase of 4.8 °C in temperature. This increase also reduced the viability of BRS Acauã and BRS Pajeú pollen by 34 and 7%, respectively. Heating increased stomatal opening and transpiration but reduced chlorophyll content. The enzymatic response varied according to cultivars and temperature. Changes in photosynthetic and enzymatic activities contribute to reducing pollen viability and productivity. BRS Acauã was the most affected, with an 82% reduction in the number of seeds and a 70% reduction in production. BRS Gurguéia maintained its production, even with an increase of 4.8 °C, and can be selected as a cultivar with the potential to tolerate high temperatures as it maintained pollen viability, with less flower abortion, with the synchrony of physiological and biochemical responses and, consequently, greater production.

Condições ambientais adversas, como o aumento da temperatura do ar, tem impacto sobre o crescimento inicial das plantas, interferindo no potencial de rendimento dos cultivos. Assim, objetivou-se avaliar o efeito do aumento da temperatura no estabelecimento inicial de plantas de mandioca. O experimento foi realizado em câmaras de crescimento, com delineamento inteiramente casualizado em esquema fatorial 3x2 (cultivares x regimes de temperatura), com cinco repetições, durante 165 dias. Foram utilizadas mudas de mandioca das cultivares BRS 417, BRS 420 e BRS CS01 e os regimes de temperatura: T1 (20-26-33 °C) e T2 (24.8-30.8-37.8 °C). Os parâmetros fisiológicos foram afetados negativamente pelo aumento da temperatura. Essas alterações fisiológicas resultaram no aumento da temperatura foliar. A cultivar BRS 420 apresentou maior diâmetro do caule, quando comparada às demais, com uma média de 4,63 mm. O regime de temperatura de 24.8-30.8-37.8 °C contribuiu para maior altura das plantas das cultivares BRS 420 e BRS CS01, com média de 104.28 e 89.54 cm respectivamente. O aumento da temperatura também contribuiu para maior produção de biomassa da parte aérea, com um aumento de massa fresca de 41% e 52% e massa seca de 20% e 37% para BRS 420 e BRS CS01, respectivamente. A massa fresca do sistema radicular foi maior com o aumento da temperatura para as três cultivares analisadas, com destaque para BRS 420, que também apresentou maior produção de massa seca das raízes, independentemente do regime de temperatura. O aumento da temperatura do ar, com regime diário de 24.8-30.8-37.8 °C favoreceu o crescimento e desenvolvimento das plantas jovens de mandioca, contribuindo para o seu estabelecimento, mesmo com alterações nas respostas fisiológicas.