ABSTRACT Sugarcane irrigation is one of the main technologies to increase productivity and profitability in the sugar-energy sector. However, to improve the management of water resources in Brazil, growers need to obtain a water rights permitfrom regulatory agencies. The calculation of water rights is determined from data based on estimates of rainfall and reference evapotranspiration (ETo) provided by the Agência Nacional de Águas e Saneamento Básico (ANA). The primary hypothesis of this study was that the method proposed by ANA to calculate water rights did not provide operational security since it lacked an adequate probabilistic character. As a corollary, we included a secondary hypothesis stating that determining flows through the simplified FAO method proposed in the CROPWAT 8.0 manual displayed vulnerability due to the criteria to choose the representative years. This research aimed to compare such methodologies with a more detailed case study (standard method), taking into account the temporal variability of these estimates, the irrigation criteria, and the probability of occurrence of ETo and rainfall to determine water rights for sugarcane irrigation. During the period between Apr and Sept (dry period), the calculation method proposed by ANA met the needs of the project. However, when rainfall was concentrated (Oct to Mar), the calculation method tended to underestimate the monthly values of available flows. The simplified method proposed by FAO and the alternative method proposed here approached ideal conditions. sugarenergy sugar energy sector However Brazil agencies (ETo ANA. . (ANA) character corollary 80 8 0 8. years standard method, , method) dry period, period) project Oct Mar, Mar Mar) conditions (ANA

ABSTRACT Agricultural productivity is closely related to soil physical attributes, specifically those that affect the soil-water relationship, as the soil serves as the main water reservoir for plants. This research aimed to determine the field capacity for different soils, using equations based on the water retention curve. The database used included 150 soil profiles from studies published by other authors encompassing information related to textural classification, soil bulk density, particle density and soil water retention. The inflection point for each soil profile and the corresponding matrix potential were generated. Multiple correlations were established between volumetric moisture at field capacity and clay, silt and sand contents. The calculated inflection point can be an estimator of field capacity, what may facilitate and speed up the calculation of water availability. attributes soilwater relationship plants soils curve 15 classification generated clay contents availability 1

RESUMO A produtividade agrícola está intimamente relacionada aos atributos físicos do solo, em especial àqueles que afetam a relação solo-água, uma vez que o solo se constitui no principal reservatório hídrico para as plantas. Objetivou-se determinar a capacidade de campo para diferentes solos, a partir de equações baseadas na curva de retenção de umidade. Foi utilizado um banco de dados com 150 perfis obtidos de trabalhos publicados por outros autores, com informações sobre classificação textural, densidade aparente do solo, densidade de partícula e retenção de água no solo. Foi gerado, para cada perfil, o ponto de inflexão, assim como o potencial matricial correspondente ao seu valor. Foram estabelecidas correlações múltiplas entre a umidade volumétrica na capacidade de campo e os teores de argila, silte e areia. O ponto de inflexão calculado pode ser um estimador da capacidade de campo, o que pode facilitar e agilizar o cálculo de disponibilidade de água. soloágua, soloágua água, solo-água plantas Objetivouse Objetivou solos 15 autores textural gerado perfil valor argila areia 1

ABSTRACT: The use of plastic mulching and high frequency hydroponic drip irrigation (intensive production methods) watering cycle may increase tabasco pepper crop production per unit area. To test this hypothesis, two randomized block experiments were conducted in a greenhouse, using a 2 × 4 factorial scheme with two contrasting soil types (sandy loam and loamy soil), two mulching conditions of soil cover (SC), and no soil cover (NC) at four frequencies: 1, 3, 12, and 24 irrigations every three days. The growth and yield pepper components were evaluated and the water use efficiency (WUE) was calculated. Mulching did increase fruit dry mass percentage (FDMP), WUE, and potassium use efficiency (KUE) in sandy loam soil. The greater frequency fertigation did not increase fruit fresh mass (FFM), number of fruits (NF), fruit average mass (FAM), fruit dry mass (FDM), FDMP, or WUE in sandy loam and loamy soils. Tabasco pepper has a permanent shrub growth habit that is somewhat different from horticultural crops, besides it is usually responsive to high frequency irrigation under vegetative intensive growth.

ABSTRACT: Awareness of evapotranspiration (ET) and crop coefficient (Kc) is necessary for irrigation management in coffee crops. ET and Kc spatial variabilities are disregarded in traditional methods. Methods based on radiometric measurements have potential to obtain these spatialized variables. The Kc curve and spatial variability of actual evapotranspiration (ETa) were determined using images from Landsat 8 satellite. We used images of young and adult coffee plantations from OLI (Operational Land Imager) and TIRS (Thermal Infrared Sensor) sensors over a two-year period. Evapotranspiration was estimated using the Surface Energy Balance Algorithm for Land (SEBAL). Moreover, the reference evapotranspiration (ETo) was estimated through the Penman-Monteith method. We obtained the values for the evapotranspiration fraction (ETf), analogous to Kc, according to ET and ETo values. The study was conducted in Buritis, Minas Gerais State, Brazil, in areas cropped with Coffea arabica irrigated by central pivots. A comparative analysis was made using different statistical indices. Average ETa was 2.17 mm d−1 for young coffee plantations, , and the Kc mean value was 0.6. For adult coffee plantations, average ETa was 3.95 mm d−1, , and the K mean value was 0.85. The ET and K data obtained based on the SEBAL algorithm displayed similar values to studies that used traditional methods. This model has huge potential to estimate ET of different stages of coffee plantation for the region studied.

RESUMO A Espanha possui um terço de toda área irrigada da Europa. A área irrigada no país responde por 15% da área cultivada e quase 60% da produção agrícola nacional. O conhecimento da variabilidade espacial e temporal da evapotranspiração de referência (ETo) e da teoria probabilística dos eventos extremos é um ponto essencial para elaboração de projetos sustentáveis de irrigação. O objetivo do trabalho foi analisar a distribuição de frequência que melhor descreve a ETo visando o dimensionamento de sistemas de irrigação da região de Andaluzia, Espanha. Foram utilizados dados de ETo de 56 estações meteorológicas com extensão das séries entre os anos de 2001 a 2015. Estes valores de ETo foram acumulados em três períodos consecutivos de dias. Para todos os períodos acumulados ajustaram-se nove distribuições de probabilidade. A distribuição de probabilidade que melhor descreveu a ETo visando o dimensionamento de sistemas de irrigação da região foi a Gumbel II. A ETo diária máxima a ser considerada em projetos de irrigação na mesma região é de 10 mm, em média. Já as ETo acumuladas em períodos de 5, 10 e 30 dias que devem ser consideradas são, em média, de 42 mm, 78 mm e 224 mm, respectivamente.

ABSTRACT Spain contains a third the entire irrigated area of Europe, accounting for 15% of the cultivated area of the country and almost 60% of the national agricultural production. Knowledge of the spatial and temporal variability of reference evapotranspiration (ETo) and the probabilistic theory of extreme events is crucial for the elaboration of sustainable irrigation projects. The objective of this work was to define the frequency distribution that best describes ETo for the design of irrigation systems in the region of Andalusia. We used ETo data for the period 2001 to 2015 from 56 meteorological stations. The values were accumulated over three consecutive days. For all accumulated periods, nine probability distributions were adjusted. The probability distribution that best described ETo for the design of irrigation systems in the region was the Gumbel II distribution. The maximum daily ETo to be considered in irrigation projects in this region is, on average, 10 mm. The accumulated ETo for periods of 5, 10, and 30 days that should be considered are, on average, 42 mm, 78, mm and 224 mm, respectively.

ABSTRACT. The leaf area index (LAI) is relevant in studies of phenomena at different scales, such as for the leaf to canopy scale and the calculation of the extinction coefficient of photosynthetically active radiation (kPAR), providing input for the parameterization of physiological basis models. The objective of this work was to verify the variation of the LAI and the coffee kPAR subjected to different drip irrigation levels (130, 100, 70, and 40%) and to compare the data obtained from radiation bar linear sensors (SunScan) in the plants that received full irrigation with the values found by other LAI estimation methodologies. The study was conducted in Piracicaba, São Paulo State, Brazil, using the species Coffea arabica cv. Red Catuaí IAC 144; a drip irrigation system was adopted, with the irrigation controlled by tensiometry. The mean LAI values were higher in the L130 (irrigation level of 130%) and L100 (irrigation level of 100%) treatments than those with deficit irrigation depths. The mean kPAR values were lower for the L130 and L100 treatments than the values found in the deficit irrigation depth treatments. When comparing SunScan to other methodologies, the mean error (ME) and absolute mean error (AME) were high.