IRRIGAÇÃO POR GOTEJAMENTO SUBSUPERFICIAL E FERTIRRIGAÇÃO DA CULTURA BRÓCOLIS

IRRIGAÇÃO POR GOTEJAMENTO SUBSUPERFICIAL E FERTIRRIGAÇÃO DA CULTURA BRÓCOLIS* KAROLINE MASO DOS REIS1; LUIZ FABIANO PALARETTI2; ANTÔNIO CARLOS BARRETO1 E JOSÉ RENATO ZANINI2 *Artigo extraído da tese da primeira autora 1 Instituto Federal de Educação, Ciência e Tecnologia do Triângulo Mineiro, Rua João Batista Ribeiro, 4000 Distrito Industrial II 38064-790, Uberaba, Minas Gerais, Brasil. E-mails: [email protected]; [email protected]. 2Departamento de Engenharia Rural, Faculdade de Ciências Agrárias e Veterinárias (FCAV), Universidade Estadual Paulista (UNESP), 14884-900, Jaboticabal, SP, Brasil. E-mail: [email protected]; [email protected]. 1 RESUMO A irrigação eleva a produtividade e protege os cultivos da sazonalidade das chuvas, porém, sua aplicação deve estar embasada em critérios técnicos e operacionais. O objetivo deste trabalho foi avaliar o desempenho hidráulico de tubo gotejadores e o desenvolvimento da cultura brócolis submetida à irrigação por gotejamento em superfície e subsuperfície, com e sem fertirrigação. O experimento foi montado no esquema fatorial 3x2 em blocos casualizados (DBC), com quantro repetições. Os tratamentos foram constituídos da posição do tubo gotejador nas profundidades 0,00; 0,10 e 0,20 m; e a aplicação de fertilizantes, que foi realizada via fertirrigação e adubação manual. Em relação ao tubo gotejador, avaliou-se: vazão, coeficiente de variação de vazão (CVq), coeficiente de uniformidade de Christiansen (CUC), coeficiente de uniformidade de distribuição (CUD) e grau de entupimento (GE); em relação à resposta da cultura avaliou-se: diâmetro do pedúnculo floral, diâmetro da inflorescência, diâmetro perpendicular da inflorescência, altura da inflorescência, massa fresca da inflorescência, dias do transplante até a colheita e a produtividade da água. Não foram observadas alterações significativas nas características avaliadas do tubo gotejador e na produção da cultura brócolis quanto à profundidade do tubo e a forma de aplicação dos fertilizantes. Palavras-chave: Brassica oleracea var. itálica, irrigação localizada, produtividade da água REIS, K. M.; PALARETTI , L. F.; BARRETO, A. C.; ZANINI, J. R. IRRIGATION AND FERTIGATION FOR SUBSUPERFICIAL AND SUPERFICIAL DRIP IN BROCCOLI CROP 2 ABSTRACT The use of irrigation increases yields and protects crops from the seasonality of precipitation; however, its application must be based on technical and operational criteria. This work aimed to evaluate the hydraulic performance of drip emitters and the development of the broccoli crop submitted to drip irrigation on surface and subsurface, with and without fertigation. The experiment was designed in randomized blocks (RBD), with four replications. The treatments were constituted of the positions of drip emitter at depths of 0.00; 0.10 and 0.20 m; and the application of fertilizers, that was made by fertigation and manual fertilizing. In relation to drip emitter, flow, flow variation coefficient (Cv), Christiansen uniformity coefficient (CU), distribution uniformity coefficient (DU) and degree of clogging of the emitter (Ec) were evaluated; regarding the crop response, the diameter of the flower stalk, the diameter of the inflorescence, the diameter of the inflorescence (perpendicular), height of the inflorescence, fresh mass of the inflorescence, days of transplantation until harvest and water productivity was analyzed. There were no significant changes in the characteristics evaluated of the drip emitter and in the production of broccoli crop in terms of the depth of the emitter and the way of application of the fertilizers. Keywords: Brassica oleracea var. itálica, localized irrigation, water productivity

Development and Evaluation of a Variable-Rate Irrigation Management Method in the Mississippi Delta

HighlightsWe developed and evaluated a variable-rate irrigation (VRI) management method for five crop years in the Mississippi Delta.VRI management significantly reduced irrigation water use in comparison with uniform-rate irrigation (URI). There was no significant difference in grain yield and irrigation water productivity between VRI and URI management.Soil apparent electrical conductivity (ECa) was used to delineate irrigation management zones and generate VRI prescriptions.Sensor-measured soil water content was used in irrigation scheduling.Abstract. Variable-rate irrigation (VRI) allows producers to site-specifically apply irrigation water at variable rates within a field to account for the temporal and spatial variability in soil and plant characteristics. Developing practical VRI methods and documenting the benefits of VRI application are critical to accelerate the adoption of VRI technologies. Using apparent soil electrical conductivity (ECa) and soil moisture sensors, a VRI method was developed and evaluated with corn and soybean for five crop years in the Mississippi Delta. Soil ECa of the study fields was mapped and used to delineate VRI management zones and create VRI prescriptions. Irrigation was scheduled using soil volumetric water content measured by soil moisture sensors. A center pivot VRI system was employed to deliver irrigation water according to the VRI prescription. Grain yield, irrigation water use, and irrigation water productivity in the VRI treatment were determined and compared with that in a uniform-rate irrigation (URI) treatment. Results showed that the grain yield and irrigation water productivity between the VRI and URI treatments were not statistically different with both corn and soybean crops. The VRI management significantly reduced the amount of irrigation water by 22% in corn and by 11% in soybean (p = 0.05). Adoption of VRI management could improve irrigation water use efficiency in the Mississippi Delta. Keywords: Soil electrical conductivity, Soil moisture sensor, Variable rate irrigation, Water management.

Studying Yield and Water Productivity of Maize at Enhanced Level of Temperature Using DSSAT 4.7.5

Climate variability has been and continues to be, the principal source of fluctuations in global food production in countries of the developing world and is of serious concern. Agriculture, with its allied sectors, is unquestionably are highly dependent on weather conditions, any weather aberrations cause atmospheric and other forms of stress and in turn, will increase the vulnerability of these farmers to economic losses. Process-based models use simplified functions to express the interactions between crop growth and the major environmental factors that affect crops (i.e., climate, soils, and management), and many have been used in climate impact assessments. The climatic scenario from A1B scenario 2011-2090 extracted from PRECIS run shows that overall maximum and minimum temperature increase by 5.39°C (±1.76) and 5.08°C (±1.37). A decrease of about 20 quintals was recorded when maximum temperature was enhanced by +4°C and about 10 quintals decreased at +2°C. Enhancement of minimum temperature by +3°C shows a decrease of about 16 quintals in tops weight. Combination of both minimum and maximum temperature remarkably decreased grain yield at (maximum & minimum +2°C) up to 25.41%. Max. temperature lead to staggering in the irrigation water productivity, however, a consistant increase in the irrigation water productivity was realised with an increase in minimum temperature. Dry matter productivity of 50 kg DM /ha/mm [ET] was observed with the increase of 1°C in both Max. and Min. temperatures and the lowest value of (16.7 kg DM /ha/mm[ET]) was recorded when the crop is supposed to grow at enhanced level maximum temperature by +4°C both maximum and minimum temperature. Increase in the both max and minimum temperature by +1°C lead to maximum irrigation water productivity of 22.4 (kg[yield]/ha/mm[irrig]) and the lowest irrigation water productivity of 16.7 (kg[yield]/ha/mm[irrig]) was registerd when both max. as well as min. temp. was raised by +4°C minimum temperature.

A novel regional irrigation water productivity model coupling irrigation- and drainage-driven soil hydrology and salinity dynamics and shallow groundwater movement in arid regions in China

The temporal and spatial distributions of regional irrigation water productivity (RIWP) are crucial for making decisions related to agriculture, especially in arid irrigated areas with complex cropping patterns. Thus, in this study, we developed a new RIWP model for an irrigated agricultural area with complex cropping patterns. The model couples the irrigation- and drainage-driven soil water and salinity dynamics and shallow groundwater movement in order to quantify the temporal and spatial distributions of the target hydrological and biophysical variables. We divided the study area into 1 km × 1 km hydrological response units (HRUs). In each HRU, we considered four land use types: sunflower fields, wheat fields, maize fields, and uncultivated lands (bare soil). We coupled the regional soil hydrological processes and groundwater flow by taking a weighted average of the water exchange between unsaturated soil and groundwater under different land use types. The RIWP model was calibrated and validated using 8 years of hydrological variables obtained from regional observation sites in a typical arid irrigation area in North China, the Hetao Irrigation District. The model simulated soil moisture and salinity reasonably well as well as groundwater table depths and salinity. However, overestimations of groundwater discharge were detected in both the calibration and validation due to the assumption of well-operated drainage ditch conditions; regional evapotranspiration (ET) was reasonably estimated, whereas ET in the uncultivated area was slightly underestimated in the RIWP model. A sensitivity analysis indicated that the soil evaporation coefficient and the specific yield were the key parameters for the RIWP simulation. The results showed that the RIWP decreased from maize to sunflower to wheat from 2006 to 2013. It was also found that the maximum RIWP was reached when the groundwater table depth was between 2 and 4 m, regardless of the irrigation water depth applied. This implies the importance of groundwater table control on the RIWP. Overall, our distributed RIWP model can effectively simulate the temporal and spatial distribution of the RIWP and provide critical water allocation suggestions for decision-makers.

Penerapan Irigasi Tetes Emiter Tali Dengan Bebagai Selang Waktu Irigasi Pada Tanaman Semangka

The objectives of the research were (1) To know watermelon yield and irrigation water productivity of watermelon by used drip irrigation with nylon rope emitter on various time irrigation intervals, (2) To determined the good time irrigation interval for watermelon production by using the drip irrigation with nylon rope emitter. The research was conducted at the research field with four-time irrigation intervals were 1,2,3, and 4 days of time irrigation interval. The research was arranged in Completely Randomized Block Design. The result of the research showed that the time irrigation interval was not significantly affected yield and irrigation water productivity of watermelon. The soil moisture in the root zone at 30 cm depth of 23,23—23,88% before irrigation still in range of the available soil moisture content for plants. The average of watermelon yield and irrigation water productivity of watermelon were 5,07—5,45 kg/plant and 115,15—123,79 kg/m3. The good time interval of irrigation for watermelon production by using drip irrigation with rope emitter was 4 days time interval of irrigation.