Crop cultivation on sandy soils is susceptible to water stress. Therefore, we determined the physical-hydric attributes of a Latossolo Vermelho distrófico (Oxisol) in northwestern Paraná state, Brazil. Soil samples were collected at depth ranges of 0 to 0.2 m, 0.2 to 0.4 m, and 0.4 to 0.6 m. We measured clay, silt, sand, fine and coarse sand contents, soil particle density, soil bulk density, total porosity, microporosity, and macroporosity. We also measured soil characteristics such as saturated and unsaturated soil hydraulic conductivities, pore distribution, water retention, available water capacity, and easily available water. We also estimated soil moisture, matric potential at field capacity, and time at field capacity. Validation of associations among these soil physical-hydric attributes was performed using principal component analysis. For the sandy soils analyzed, the distributions of coarse and fine sand fractions were measured for better evaluation of the soil’s physical and hydric attributes. Higher coarse sand contents increased soil hydraulic conductivities, maximum pore diameter, and macroporosity while reducing microporosity. Fine sand content reduced conductivity and increased soil water retention in subsurface layers. Simulated sugarcane yield increased with soil water storage. These results support improving crop simulation modeling of sugarcane to support sustainable intensification in regions with sandy soils.

Brazil is the largest producer of sugarcane (Saccharum spp.) in the world, and this crop’s response to climate and soil water storage is essential for optimal management and genetic/yield improvements. The objective of our study was to build a multivariate model to estimate sugarcane yield in the subtropical conditions of the northwestern Paraná region using climatic and soil water storage variables. Observed yield data was used from experiments conducted at the Experimental Station of the Sugarcane Genetic Improvement Program of the Universidade Federal do Paraná. The sugarcane varieties RB72454, RB867515, RB966928, and RB036066 were analyzed in the 1998–2006, 2008, 2018 and 2019 harvest years. Stepwise multiple linear regression analysis with repeated cross-validation was developed to estimate sugarcane yield given climate and soil water storage variables for crop growth phases. The accumulated degree days in Phases I and II and soil water storage in Phase II of development significantly impacted sugarcane yield. The multiple linear regression model, with accumulated degree days and soil water storage in Phases I and II of development, successfully predicted sugarcane yield for analyzed varieties. Sugarcane production models like the one we developed can improve crop management for greater sustainability and climate change adaption in Brazil and other areas.

Brazil’s midwest has rapidly expanded large-scale commodity crops such as soybeans and maize. We surveyed both agricultural producers and agricultural professionals in the middle-north region of Mato Grosso state, Brazil. Agricultural professionals provide technical support to agricultural producers and both are served by Assistência Técnica e Extensão Rural (ATER) with nationally and internationally recognized extension outreach. Our objectives were to define and contrast agricultural producer and professional characteristics, especially source(s) relied upon for agricultural training. There were 94 agricultural producers and 89 agricultural professionals that responded to our surveys, which were summarized and contrasted using statistical software. There was a predominance of male farmers, married with a broad age range. Agricultural professionals who advise producers had a high educational level. Producers and professionals were most reliant on private sector agricultural companies and business support organizations for agricultural training, versus public institutions such as universities and state/federal agencies. In the state of Mato Grosso, extension outreach can involve joint efforts by public and private sector entities. However, more targeted efforts are needed to ensure that public sector research is more equally used by agricultural producers and professionals in the region, especially during field days and face-to-face technical lectures during the off-season.

RESPOSTAS FISIOLÓGICAS E PRODUTIVAS DA PALMA DE ÓLEO IRRIGADA EM FASE INICIAL DE DESENVOLVIMENTO JESSICA LIMA VIANA¹; CORNÉLIO ALBERTO ZOLIN²; VANESSA QUITETE RIBEIRO DA SILVA² E ADILSON PACHECO DE SOUZA^{3   1} Programa de Pós-Graduação em Ciência do Solo, Universidade Federal do Paraná (UFPR), Rua dos Funcionários, 1540, Juvevê, CEP: 80035-050, Curitiba, Paraná, Brasil, jessica_llivia@hotmail.com. ² Pesquisador(a), Embrapa Agrossilvipastoril, Rodovia dos Pioneiros MT-222, Km 2,5, Zona Rural, Caixa Postal: 343, CEP: 78550-970, Sinop, Mato Grosso, Brasil, cornelio.zolin@embrapa.br; vanessa.quitete@embrapa.br. ³ Professor, Instituto de Ciências Agrárias e Ambientais, Universidade Federal de Mato Grosso (UFMT), Avenida Alexandre Ferronato, 1200, Cidade Jardim, CEP: 78550-728, Sinop, Mato Grosso, Brasil, pachecoufmt@gmail.com.     1 RESUMO   Objetivou-se avaliar a taxa fotossintética, taxa de transpiração, condutância estomática e a eficiência do uso da água e a produtividade (número e massa fresca dos cachos por planta) de duas cultivares de palma de óleo irrigada, com 4 anos e 4 meses de idade, em Sinop-MT. O delineamento experimental adotado foi de blocos casualizados, sendo os tratamentos às disponibilidades de água no solo de 80%, 60%, 40%, 20% e 0% em parcelas subdivididas nas cultivares BRS C2501 e BRS C2528, com três repetições. A palma de óleo foi sensível ao déficit hídrico apresentando alterações nas variáveis fisiológicas e redução no número e massa fresca dos cachos. A máxima taxa fotossintética da palma de óleo (A = 23,32 µmol m^-2 s^-1) foi obtida com 80% da disponibilidade de água no solo, independentemente da cultivar. As palmas de óleo sem irrigação submetidas a deficiência hídrica recuperam a taxa de fotossíntese, transpiração e condutância estomática no período chuvoso, indicando tolerância à deficiência hídrica e eficiência na regulação estomática. Palavras-chave: déficit de pressão de vapor, Elaeais guineenses, manejo da irrigação, trocas gasosas.     VIANA, J. L.; ZOLIN, C. A.; SILVA, V. Q. R. da; SOUZA, A. P. de PHYSIOLOGICAL AND PRODUCTIVE RESPONSES OF IRRIGATED OIL PALM IN EARLY DEVELOPMENT PHASE     2 ABSTRACT   The aim of this study is to assess gas exchange (photosynthesis rate, stomatal conductance, transpiration rate and water use efficiency) and yield characteristics (number and fresh mass of bunches) of oil palm under soil water depletion levels. This study was carried out in the experimental field of Embrapa Agrossilvi pastoril, in the north region of the state of Mato Grosso. The experimental design was randomized blocks in subdivided plots. Main plots consisted of five soil water depletion levels, respectively 80%, 60%, 40%, 20% and 0%. Subplots were represented by two cultivars (BRS C2501 and BRS C2528) with three replications. The oil palm was sensitive to water deficit presenting physiological changes and reduction in number and fresh mass of bunches. The maximum photosynthetic rate of oil palms was obtained with 80% of soil water depletion level (A = 23.32 μmol m^-2 s^-1), regardless of the cultivars. Plants under strong water deficit (without irrigation) recovered the rate of photosynthesis, transpiration and stomatal conductance in the rainy season, indicating tolerance to water deficit and efficiency in stomatal regulation. Keywords: vapor pressure deficit, Elaeais guineenses, irrigation management, gas exchange.