Crop Coefficients and Transpiration of a Super Intensive Arbequina Olive Orchard using the Dual Kc Approach and the Kcb Computation with the Fraction of Ground Cover and Height

Abstract

The SIMDualKc model was used to simulate crop water requirements for a super high density olive orchard in the region of Alentejo, Portugal. This model uses the dual crop coefficient approach to estimate and partitioning the actual crop evapotranspiration (ETc act) and therefore to perform the soil water balance. The model was calibrated with 2011 tree transpiration using trunk sap flow measurements and was validated using similar data from 2012 and tested with 2013 data. Low root mean square errors (RMSE < 0.53 mm·d−1) and acceptable modelling efficiency indicators (EF > 0.25) were obtained. Further validation was performed comparing modelled ETc act with eddy covariance measurements. These indicators support the appropriateness of using SIMDualKc to guide irrigation management. The basal crop coefficient (Kcb) curves obtained with SIMDualKc for those 3 years were compared with the Kcb values computed with the Allen and Pereira approach (A&P approach) where Kcb is estimated from the fraction of ground cover and plant height considering an adjustment factor for crop stomatal control (Fr). Fr values were obtained through a trial and error procedure through comparing the Kcb estimated with this approach and with SIMDualKc. The Kcb curves obtained by both methods resulted highly correlated, which indicates that the A&P approach may be used in the irrigation management practice to estimate crop water requirements. Results of performing the soil water balance with SIMDualKc have shown that soil evaporation is a large fraction of ETc act, varying between 41% and 45% for the 3 years under study. Irrigation, applied with a drip system, represented 39 to 56% of ETc act, which shows the great importance of irrigation to achieve the water requirements of super intensive olive orchards. Nevertheless, the analysis has shown that the irrigation management adopted at the orchard produces a water deficit larger than desirable, with a ratio of ETc act to non-stressed crop evapotranspiration (ETc) varying from 70% to 94% during the mid-season, when that ratio for a eustress irrigation management could be around 90%.

Innovation Issues in Water, Agriculture and Food

“…Moreover, appropriate K cb values relative to the defined crop growth stages are proposed for computing ET c in the region and to transfer elsewhere after appropriate climate adjustment. Paço et al [7] confirm the appropriateness of using the SIMDualKc model for ET c computations and the great importance of irrigation for super intensive olive orchards in an application performed in southern Portugal. Appropriate values for K cb and K c were determined from the calibration and validation of the model.…”

“…They recommended the use of the SIMDualKc or a similar model to properly schedule irrigation. The papers referred above [5][6][7] relative to a grass crop, a horticultural crop, and a tree crop all proved the appropriateness of simply computing K cb from the fraction of ground cover and height.…”

Chemical Profiles of Polyphenols in Aqueous Infusion of Yerba Mate and Tea Mate (Ilex Paraguariensis) From Argentina, Brazil and Uruguay

“…O coeficiente de cultivo (Kc) é obtido para cada fase fenológica das plantas (Figura 2) e apresenta variação para cada espécie vegetal, sendo importante a determinação destes valores para a localidade em que o mesmo é utilizado (BASSOI et al, 2007), já que o clima é variável para cada região do mundo, o que torna o uso do Kc de uma cultura calculado para uma localidade e usado em outra região, inviável, já que as condições agrometeológicas podem variar bastante. Devido a redução da evaporação, alguns autores (BONACHELA et al, 2001;DING et al, 2013;PAÇO et al, 2019;SALADO-NAVARRO;SINCLAIR;MORANDINI, 2013;YONTS et al, 2018) realizaram diversos estudos sobre a cobertura vegetal (ALLEN; PEREIRA, 2009) em função da ETc e altura da planta, estes autores obtiveram a seguinte equação (3):…”

“…Considerando a falta de água nas regiões semiáridas, a adoção de técnicas que promovam melhorias no desempenho das culturas e aumentem a eficiência do uso da água, torna-se cada vez mais importante na produção agrícola, tal como o uso da cobertura de solo ou "mulching". O uso de coberturas mortas no solo é uma prática recomendada, em particular nas regiões semiáridas, contribuindo para a melhoria do desempenho das culturas (PAÇO et al, 2019), redução das perdas de água do solo PEREIRA, 2009;BALUGANI et al, 2018;DING et al, 2013;SALADO-NAVARRO;SINCLAIR;MORANDINI, 2013;YONTS et al, 2018) e redução da erosão superficial (SOUZA; MONTENEGRO; MONTENEGRO, 2008).…”

Water Requirements of Crops under Various Kc Coefficient Approaches by Using Water Evaluation and Planning (WEAP)

“…Estimating the values of reference evapotranspiration (ET0) is important, where crop evapotranspiration (ETc) calculated by depended on it. reference evapotranspiration (ET0) represents reference surface of grass with height 0.12m and fixed resistance 70 s/m [5,6].…”