Anderson Ramos de Oliveira

Developing and selecting genotypes that are responsive or tolerant to variations in water availability is essential for sugarcane production. The aim of this study was to evaluate the performance of 32 sugarcane genotypes under different water conditions. The responses of physiological variables as a function of different irrigation levels were evaluated. The experiment used a Randomized Complete Block Design (RCBD) in a split-plot arrangement. Four irrigation levels (20 %, 40 %, 60 %, and 100 % of crop evapotranspiration) were allocated to main plots, and the subplots were represented by 32 genotypes belonging to different genera and species. The evaluated physiological variables of the plants were photosynthesis rate (A), stomatal conductance (gs), quantum yield of CO2 assimilation (PhiCO2), and transpiration rate (E). Leaf vapor pressure deficit (VpdL) was estimated based on leaf temperature. The results revealed that genotypes 10, 26, and 29 consistently maintained high physiological performance across all irrigation levels, whereas genotype 7 showed notable resilience under water deficit. These genotypes are identified as promising candidates for cultivation under water‑limited conditions and may support the selection of efficient, drought‑tolerant material for semi‑arid regions.

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 objective of this review was to describe the research implemented and with potential use in the Brazilian semiarid region for adaptation to climate change. The study covered topics such as climate risk mitigation, phytosanitary responses, crop resilience to heat and water stress, forage species that are native and cultivated in livestock systems, crop-livestock-forestry integration, microbial inputs, soil quality and carbon sequestration, and water technologies. For this, searches were conducted in databases and repositories of government agencies and international organizations. As a strategy, a set of terms, including the cited topics, were associated with the term “Brazilian semiarid”. This review also highlights critical research gaps in these domains. From this analysis, it is notable that ongoing adaptation technologies have often been applied in isolation in rural landscapes, indicating that the main challenge of research lies in developing synergies between these technologies.

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.

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.

Diante do elevado potencial produtivo da cana-de-açúcar na região do Vale do Submédio do São Francisco, a identificação das doses de adubo que maximizem a qualidade dos caracteres de interesse da agroindústria canavieira torna-se um fator preponderante para sustentabilidade do cultivo. Objetivou-se com este trabalho, definir as doses de nitrogênio e potássio, via fertirrigação por gotejamento subsuperficial, que proporcione a máxima qualidade agroindustrial da variedade de cana-de-açúcar RB 92579, na região do Submédio do São Francisco. O experimento foi conduzido em condições de campo, sendo os tratamentos provenientes do esquema fatorial 5 x 5 x 3, dispostos no delineamento em blocos ao acaso, com três repetições, sendo cinco doses de nitrogênio (0; 40; 80; 160 e 320 kg ha^-1 de N), cinco doses de potássio (0; 60; 120; 240 e 480 kg ha^-1de K₂O) e três ciclos de cultivo (cana planta e 1ª e 2ª soca). Constatou-se que as doses de 60 kg ha^-1 de N e 320 kg ha^-1 de K₂O, aplicadas via fertirrigação por gotejamento subsuperficial, proporcionam a máxima qualidade agroindustrial da cana-de-açúcar, variedade RB 92579. Contudo, a qualidade agroindustrial da cana atende às normas técnicas básicas, com as características nutricionais do próprio solo em estudo, nos três ciclos avaliados.

In order to obtain an efficient cultivation of grain sorghum in production systems that use saline water, an adequate management becomes necessary for maximizing its production. The present study aimed to evaluate the effect of the application of leaching fractions in the saline water irrigation management on the production of sorghum varieties and on the distribution of water and salts in the soil profile, under semiarid conditions. The study was carried out in the municipality of Petrolina, semiarid region of Brazil. The experimental design was randomized blocks, with four replicates, in split-split plots; four leaching fractions (LF): 0, 5, 10, and 15% with saline water from artesian well in the plots, three varieties of grain sorghum: 1011-IPA, 2502-IPA and Ponta Negra in the subplots, and two crop cycles (1st and 2nd cut) in the sub-subplots. The evaluated variables were distribution of water and salts in the soil profile, biometric variables, fresh biomass, dry biomass, and grain yield. Application of leaching fractions of up 15% in saline water irrigation promotes better distribution of salts in the soil profile, with increments of up to 60% in the grain yield of the sorghum varieties evaluated. The production of the varieties 1011-IPA and Ponta Negra is a feasible alternative in systems irrigated with saline water with average electrical conductivity of 4.19 dS m-1, in Ultisol, under semiarid conditions.

The objective of this study was to evaluate the influence of leaching fraction on the biometric and production characteristics and technological quality of the juice of sugarcane varieties grown in saline soil in the Brazilian semiarid region. The experimental design was in randomized blocks, with three repetitions, in a 2 × 3 × 3 factorial scheme, corresponding to two sugarcane cultivation cycles: plant cane and ratoon cane; three sugarcane varieties: RB72454, SP943206 and VAT90212; and, three leaching fractions of irrigation water: 0; 9.1; and 16.6%. Number of living leaves, number of internodes, leaf area, stem diameter, plant height, number of tillers, yield, total soluble solids content (°Brix), percentage of industrial fiber, juice purity, juice Pol%, cane Pol% and total recoverable sugar were evaluated. At the end of the two crop cycles, water use efficiency was determined. The varieties SP943206 and VAT90212 showed higher yield under leaching fraction of irrigation water of 9.1% in both cycles, and higher water use efficiency values were observed for the variety VAT90212. Application of leaching fractions to reduce soil salinity does not promote changes in the technological quality of the sugarcane varieties RB72454, SP943206 and VAT90212.

MANEJO E PRODUÇÃO DE PALHADA DA CANA-DE-AÇÚCAR EM UM SISTEMA IRRIGADO POR GOTEJAMENTO SUBSUPERFICIAL PARA GERAÇÃO DE BIOETANOL ANDERSON RAMOS DE OLIVEIRA1, WELSON LIMA SIMÕES1 1 Embrapa Semiárido, Rodovia BR-428, Km 152, s/n, Zona Rural, CEP 56302-970, Petrolina, PE, Brasil, e-mail: anderson.oliveira@embrapa.br, welson.simoes@embrapa.br RESUMO: Práticas agrícolas que contemplam a sustentabilidade do sistema de produção da cana-de-açúcar têm sido cada vez mais demandadas pela sociedade. A palhada disponibilizada na colheita da cana-de-açúcar, sem queima, pode ser utilizada para a cogeração de energia na forma de bioetanol. Assim, objetivou-se com este trabalho avaliar a produtividade de palhada de cana-de-açúcar e estimar o rendimento de bioetanol de segunda geração - E2G, em um sistema irrigado por gotejamento subsuperficial, sob diferentes percentuais de manutenção de palhada sobre a superfície do solo. O estudo foi desenvolvido na Usina Agrovale S.A., em Juazeiro, BA. Adotou-se o delineamento em blocos casualizados com cinco tratamentos, correspondentes aos percentuais de manutenção de palhada sobre o solo: 0, 25, 50, 75 e 100%, com quatro repetições, durante quatro ciclos de cultivo. Avaliou-se a produtividade de palhada remanescente após as colheitas e estimou-se o rendimento de bioetanol. A produtividade de palhada da cana-de-açúcar na colheita foi influenciada pela porcentagem de palhada remanescente mantida sobre o solo. A cultivar VAT90212 apresenta maior produtividade de palhada no ciclo de cana-planta. O rendimento de E2G proveniente da palhada aumenta o potencial de produtividade total de bioetanol de cana-de-açúcar por hectare. Palavras-chave: E2G, sustentabilidade, bioenergia, Semiárido. MANAGEMENT AND PRODUCTION OF SUGARCANE STRAW UNDER SUBSURFACE DRIP IRRIGATION FOR BIOETHANOL GENERATION Sustainable agricultural practices in the sugarcane production system have been increasingly demanded by society. The amount of sugarcane straw available in the harvest, without burning, can be used as energy for second-generation bioethanol production. The objectives of this work were to evaluate the productivity of sugarcane straw and to estimate the yield of second-generation bioethanol, under subsurface drip irrigation, using straw at different percentages of soil surface coverage. The study was conducted at Agrovale S.A. in Juazeiro, BA, Brazil. A randomized block design with five treatments, corresponding to the levels of straw soil surface coverage was used: 0, 25, 50, 75, and 100%, with four replications, during four crop cycles. The yield of remaining straw on the soil after the harvest was evaluated and the yield of bioethanol was estimated. The yield of sugarcane straw at harvest was influenced by the percentage of remaining straw soil surface coverage. The cultivar VAT90212 shows higher straw productivity in the sugarcane plant cycle. The yield of the second generation bioethanol from the straw increases the total productivity potential of bioethanol from sugarcane per hectare. Keywords: E2G, sustainability, bioenergy, Semi-arid.