Se realizo un ensayo para determinar: a) Los requerimientos hidricos de perales asiaticos de tres anos de edad b) La respuesta del peral asiatico en cuanto a crecimiento vegetativo bajo dos metodos de riego, goteo y microaspersion y diferentes niveles de reposicion de agua. c) Los coeficientes de cultivo Kc recomendables para este frutal. La variedad utilizada fue Chojuro, con una densidad de 666 arboles por hectarea equivalente a una distancia de plantacion de 3x5 metros. Los parametros de crecimiento evaluados fueron: largo de ramillas, diametro de tronco, perimetro de tronco. Ademas se hizo la evaluacion de parametros de produccion: Kilos de fruta cosechados, presion de pulpa, solidos solubles, color de epicarpio. Las conclusiones mas importantes son: El perimetro de tronco es un buen indicador del efecto del agua en el desarrollo del arbol. La mayor produccion en ambos metodos de riego, se registro para el subtratamiento de 75 de reposicion de agua disminuyendo con niveles mayores o menores de aplicacion. Sin embargo entre ambos metodos de riego tuvo mejor respuesta el goteo. La maxima produccion se tiene alrededor de los 5.500 a 5.900 metros cubicos por hectarea de agua aplicada. Los coeficientes de cultivo (Kc) recomendados para perales asiaticos es de 0.5 para enero y 0.89 para febrero. La cantidad de agua aplicada tiene un mayor efecto en la produccion final de perales asiaticos que el metodo de riego utilizado.

This study attempt to simulate the effect of forest structure on the distribution of rainfall water in the soil. Nutrient supplies to the forest soil are estimated in 5 hypothetical stages of development in the Mediterranean forest, based upon the measurements of water flows and their corresponding chemical compositions made in Poblet holm-oak forest.

A study was carried out, to determine the effects of different water levels on the physiological, vegetative and productive parameters of four year-old pear trees (Beurre Bosc) under drip irrigation. For each treatment the water application rate was determined by the pan evaporation (25, 50, 75 and 100 per cent of replacement). Randomized design with four treatments and four replicates were used as statistical method. Further, means were analyzed by Tukey test. Yield and fruits number -productive parameters- had response by increasing application of water in pear trees. Soluble solids and pressure, were not affected by the levels of water application. The highest values for fruit quality were found in the 50 and 25 per cent replacement treatment. There was no response to different levels of water in volume and mean weight. The highest transpiration rate was found between December 1991 and March 1992 for a 100 per cent of water replacement treatment. However there was no difference in transpiration for all other treatments. It must emphasize that for all treatments, the higher transpiration rate occurs around the 15 hours of the day. Diffusive resistance did not show differences between treatment. Similar values were found between the 100 and 25 per cent of water replacement treatment, and between 75 and 50 per cent of replacement. Leaves temperature results do not agree with those of the literature, The leaves temperatures were slightly higher in 100 per cent of water replacement, and it seems that there are no differences due to the levels of water. There is a positive relation between vegetative parameters and water levels for pear trees, because the highest values in branch length, diameter and stem perimeter were attained in 100 per cent of water replacement treatment. The water volume applied ranged between 1753 and 6846 cubic meter per ha during the irrigation period November 1991 and April 1992.

Se realizo un ensayo de campo cuyos objetivos eran determinar el efecto de la aplicacion de distintos niveles de agua bajo riego por microjet y goteo, tanto en los parametros fisiologicos como de produccion en una plantacion de arandanos highbush cv. Bluetta de segundo ano. Los tratamientos consistieron en la aplicacion de agua bajo riego por microjet y goteo. Los subtratamientos fueron distintos niveles de aplicacion de agua correspondientes a 80, 60, 40, y 20 % de reposicion de evapotranspiracion de bandeja. Los resultados obtenidos permiten concluir que: -La produccion de fruta es significativamente superior en riego por goteo que por microjet. -A un mayor volumen de agua aplicada se obtiene una mayor produccion de fruta. -El peso promedio de las frutos esta directamente relacionado con la cantidad de agua aplicada y no con el metodo de riego utilizado. -Los solidos solubles del fruto disminuyen al aumentar los niveles de agua aplicada en microjet y goteo. -En la medida que aumenta el nivel de agua aplicada se incrementa la tasa de transpiracion, y disminuye al resistencia difusiva y la temperatura foliar con ambos metodos de riego.-Las relaciones de evopotranspiracion aumentan al incrementar el agua aplicado.

This study shows the most important chemical characteristics of throughfall and stemflow in three species of Mediterranean holm-oak forest (Quercus ilex, Arbutus unedo y Phillyrea media), as well as their relationship with rainfall water chemistry and dry deposition. At the same time, it compares 3 models to evaluate the importance and amount of wet and dry deposition, as well as of leaching, in nutrients present in throughfall and stemflow.