[EN] This research analyses the subjective crop yield-water relationship and proposes a method to determine water supply in irrigated olives. The probability density for water response functions (PDF) is elicited from a series of interviews carried out on a wide group of farmers. The elicitation technique is based upon the triangular distribution (highest possible, most frequent and lowest possible) and estimates of yield related to water supply (low, ‘normal’ and full irrigation). The model presented illustrates the possibility of implementing simple decision models to support farmers to manage water considering the objectives of maximizing profit and minimizing risk | [ES] La investigación analiza la función subjetiva de producción de agua (respuesta producción-riego). Se han obtenido funciones de densidad de probabilidad de respuesta al riego basadas en la función triangular (rendimiento ‘más probable’, ‘pesimista’ y ‘optimista’) correspondientes a diferentes dosis de riego (‘completo’, ‘medio’ y ‘bajo’). A partir de esta información se plantea un modelo de decisión de tipo normativo para determinar la dosis óptima de riego en olivar intensivo que incluye rentabilidad esperada y riesgo entendido como la probabilidad de no alcanzar un umbral prefijado de ingresos | SWORD | Berbel, J.; Gutiérrez-Martín, C. (2015). Farmer’s subjective elicited water response function for intensive olives and compromise programming method for irrigation supply decision. Economía Agraria y Recursos Naturales - Agricultural and Resource Economics. 15(2):51-68. https://doi.org/10.7201/earn.2015.02.03 | 2 | This research has been financed by Secretaría General de Ciencia, Tecnología e Innovación (MINECO). We thank our colleagues L. Mateos and F. Orgaz who provided insight and expertise that greatly assisted the research, and we also thank to the anonymous reviewers whose comments improved the earlier version of the manuscript. | 68 | 51 | 15

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. | El municipio de Facatativa, lugar donde se realizo la investigacion, se encuentra ubicado en la Sabana de Bogota (Departamento de Cundinamarca), zona especializada en la producción de flores, y que en conjunto con otras regiones productoras del departamento, representan alrededor del 72% de la producción nacional. Establecer la cantidad de agua y el momento de aplicación es un factor clave que contribuye a obtener la calidad y produccion requeridas, conforme con las exigencias en cultivos comerciales como la rosa. El objetivo del presente trabajo fue evaluar el efecto de tres laminas de riego en Rosa sp. Variedad Vendela en sustrato (80% cascarilla de arroz tostada y 20% compost), con base en la evapotranspiracion y porcentaje de drenaje, en invernadero en la Sabana de Bogota. El experimento se realizo en dos ciclos durante el ano 2014. Fue evaluada la produccion y calidad de la cosecha, con tres laminas de riego, un tratamiento control (T1) con una lamina del 100% de la evapotranspiracion de cultivo (ETc) y el porcentaje de drenaje (% D), un T2 y T3 equivalentes al 80 y 65% de T1, respectivamente. Se aplicaron 15.04, 12.39 y 10.35 m3 por cama, durante los dos ciclos, en T1, T2 y T3, representando una reducción del 17.6 y 31.2% para T2 y T3, respectivamente, con respecto al tratamiento control. La produccion de tallos florares, el diametro y la longitud del boton no presento diferencias significativas (P<0.05) de acuerdo con la prueba de Duncan; sin embargo, el T1 tuvo la mayor cantidad de tallos. La longitud y diametro del tallo, el coeficiente de cultivo Kc y la eficiencia en el uso del agua (WUE) presentaron diferencias significativas entre tratamientos. Las curvas de crecimiento presentaron un incremento continuo, con ajuste al modelo logistico.

O efeito de diferentes niveis de nitrogenio na cultura do milho, em plantios isolados e consorciado com a cultura do caupi, foi estudado durante tres anos consecutivos no municipio de Petrolina, PE, em um Podzolico Vermelho-Amarelo Planossolico (Terra Bruna Estruturada), com baixa fertilidade. O delineamento usado foi o de blocos ao acaso com quatro repeticoes no primeiro e no terceiro anos e tres no segundo; os tratamentos constaram de cinco niveis de nitrogenio (0, 40, 80, 120 e 160 kg/ha de N). Os resultados obtidos apresentaram variacoes de ano para ano, dada a instabilidade em quantidade e distribuicao das precipitacoes pluviais. O milho nao respondeu aos diferentes niveis de nitrogenio, que chegaram a ter um efeito negativo no plantio isolado, a proporcaoque aumentaram. As produtividades de milho foram muito baixas no consorcio, correspondendo a apenas um terco do plantio isolado. O caupi apresentou baixas produtividades no consorcio, com proporcoes que variam de 30% a 53% de plantio isolado. Os valores calculados para o idice "Uso Eficiende de Terra" (UET) nao foram maiores que um.