The irrigation of crops represents 70% of the world’s water use. For crops grown in high-altitude tropical climates, due to the decrease in rainfall with increasing altitude, along with the effects of global warming, it is necessary to propose alternatives for sustainable fruit production with reduced water consumption. This study was carried out in Sesquilé, Colombia (South America), at an altitude of 2595 m a.s.l. for two successive years with pear trees, var. Triunfo de Viena. The objective of this work was to determine the effect of regulated deficit irrigation (RDI) on the absolute and relative growth rates of the equatorial diameter of the fruits, the fresh and dry weights, the number of fruits, the yield per tree and the water potential of the fruits. In 2014, during the rapid growth phase of the fruit, one group of plants was irrigated at 100% of the crop evapotranspiration (ETc) (control), another at 74% and a third group at 60%. In 2015, the three groups were irrigated at 100%, 48% and 27% of the ETc. The use of RDI did not significantly affect the growth of the fruits. This study showed that the ‘Triunfo de Viena’ pear tree not only has sufficient adaptive reserves, but also has good ecological plasticity under water stress conditions in high-altitude tropical climates. In cases where water is a limiting factor for pear tree production, RDI can obtain production rates similar to those of a regularly irrigated crop, as long as this technique is used and implemented in phenological states of low sensitivity to water stress without exceeding the tolerance limits of the plants to the stressor.

Frequent traffic of tractors in agricultural soils, promotes soil compaction and affects the flow and water availability. The aim of this research was to study the effect of compaction induced by tractor traffic on water availability in the soil under different traffic intensities on the same path (0, 1, 3, 6 and 10 passages), to two tractors with 3.3 and 2.6 ton of weights, over three different surface conditions. The study was conducted in an Andisol, representative soil of the study area. It was determined the behavior of the water retention curve, obtaining the gravitational water, available water and hygroscopic water, to 10 and 30 cm of depth. The hygroscopic water is the most prevalent with values of up to 80% of the total water present in the soil. The water retention curves showed increases in the values of field capacity and wilting point and behaviors "flattened" indicating a high sensitivity to the applied treatments, representative of compacted soils, which give the surfaces studied characteristics do not suitable for normal crop development.

Determinar el requerimiento de agua y el momento adecuado de distribución, es un factor fundamental para el cultivo de flores. El objetivo del presente trabajo fue determinar el efecto de la aplicación de tres láminas de riego sobre el desarrollo y producción del cultivo de la Rosa cv. Freedom, bajo invernadero. El experimento se realizó con tres láminas de riego en un cultivo de rosa (Rosa spp.) cv. Freedom. Se analizó el crecimiento de los tallos florales, la vida en florero, la producción y la eficiencia en el uso del agua. Los tratamientos se basaron en tres niveles de evapotranspiración de cultivo (ETc) (70, 80 y 100%). Durante el estudio, el cultivo se mantuvo en producción constante. Se aplicaron 384,87, 254,25 y 218,97 m³ correspondiente a 100, 80 e 70% de ETc respectivamente, significando un ahorro de agua de 14,0 y 21,8% en el 80 e 70% de ETc respectivamente. El coeficiente de cultivo (Kc) vario entre 0,58 y 1,65, con una media de 1,13. No se encontraron diferencias en la producción. Las curvas de crecimiento presentaron incremento continuo, con ajuste al modelo logístico. El 70% de ETc presentó la mayor eficiencia en el uso del agua, con 185 tallos m-3. La conservación media de los tallos florales fue de 12 a 15 días. La mayor causa de pérdida fue la deshidratación, que inició en el día 11, comportamiento normal del tallo floral.

Crecimiento del fruto de peral bajo el sistema de riego por goteo con una y dos líneas

The municipality of Facatativa, where the research was carried out, is located in the Bogota Plateau (Department of Cundinamarca), an area specialized in the production of flowers that, along with other producing regions of the department, represent around 72% of national production. Establishing the amount of water and the time of application is a key factor that contributes to obtain the quality and production required, according to the requirements in commercial crops, such as rose. The main objective of this study was to evaluate the effect of three irrigation depths on Rosa sp. Vendela variety in substrate (80% toasted rice husks and 20% compost), based on evapotranspiration and percentage of drainage, in a greenhouse in the Bogota Plateau. The experiment was conducted in two crop cycles during 2014. The production and quality of the harvest were evaluated with three irrigation depths: Control treatment (T1) with 100% of the crop’s evapotranspiration (ETc) and drainage percentage (% D), T2 and T3, equivalent to 80% and 65% of T1, respectively. Irrigation was applied as follows: 15.04, 12.39 and 10.35 m3 per bed were applied for two cycles in T1, T2 and T3, representing a reduction of 17.6 and 31.2% for T2 and T3, respectively, compared to the control treatment. The production of floral stems, the bud diameter and length did not have significant differences (P<0.05) according to the Duncan test; however, T1 had the highest number of stems. The length and diameter of the stem, the crop coefficient Kc and water use efficiency (WUE) presented significant differences between the treatments. The growth curves showed a continuous increase, which fit the logistic model.

The deficit irrigation controlled (RDI) as reducing water in phases of the crops where it is less sensitive to water stress, three different drip irrigation treatments were applied in pear tree crop of Triunfo de Viena variety. Control, irrigated throughout the year at 100% of estimated crop evapotranspiration (ETc); 67%ETc and 55%ETc treatments were irrigated at 67 and 55% of the (ETc), respectively during the period of rapid fruit growth (from December 28, 2011 until February 29, 2012) and at 100% (ETc) during the rest of the season. Reference evapotranspiration (ETo) was determined by the Penman-Monteith, with hourly weather data collected in a nearby meteorological station. During the test total precipitation was 53.8 mm and the water application in the control treatments was 683.0 mm. The results indicate that none of the treatments differed significantly (P≤0.05) from control in terms of yield and quality, resulting in water savings of 33 to 45% in 67%ETc and 55%ETc respectively compared to the control. The vegetative growth of shoots had a behavior defined by a sigmoid curve fitted to a four parameter logistic equation, and it was significantly reduced in the 67%ETc and 55%ETc, respect to control, at the end of the restriction.