INDISPONÍVEL

An analysis has been made of the possibilities for supplying potable water to Mejillones, Paposo and Taltal by collecting fog water. The deficiencies in the current water supplies to these localities are documented. The geographical conditions which make possible the collection of water using large fog collectors are listed and a brief theoretical approach has been given in regard to the three terrain features. This analysis was done using maps and in situ studies of the terrain. It is specifically recommended that a system of fog collection be implemented in the fishing village of Paposo because of the favorable geographical conditions and the precarious state of the present water supply.

Drought is an environment factor which affects frequently the maize crop in Mexico, where the most affected areas are near the arid zones. In these regions an option which allows improvement in plant breeding is the use of efficiency indexes. The objective of the study was to find variables related to the water use efficiency (WUE) and corn grain production based on the distribution in time of dry matter (D.M.). Three maize genotypes of contrasting growth cycle (HV-313, H-303 and Colecta 77) were planted in the 1987 summer-fall period in San Pedro, Huanusco, Zac. under four completely randomized blocks. Dry matter accumulation of each component (leaf, stem, cob, ear) and WUE were estimated biweekly throughout the growing cycle. Results indicated that the stem-leaf ratio had the highest influence (r2 = 0.70) over the WUE. The WUE for the genotypes were: 1.87, 2.23 and 1.4 g/kg for HV-313, H-303 and Colecta 77, respectively. WUE was a function of the genetic potential and vegetative cycle. | La sequia es un factor ambiental que afecta frecuentemente el cultivo de maiz en Mexico, sin embargo, las tierras mas afectadas por la frecuencia e intensidad de la sequia son las situadas en las proximidades de las zonas aridas. En estas regiones una opcion que ha permitido mayores avances es el uso de indices de eficiencia. El objetivo del estudio fue encontrar variables relacionadas con la eficiencia en el uso del agua (EUA) y la produccion de grano de maiz mediante estudios de patron de produccion de materia seca (MS). Se sembraron tres genotipos de maiz (HV-313, H-303 y Colecta 77) en el periodo verano-otono de 1987 en San Pedro, Huanusco, Zac., bajo un diseno experimental de bloques al azar con cuatro repeticiones. Quincenalmente se estimo la EUA con base en un balance de humedad, y la acumulacion de MS en cada componente de la planta (hoja, tallo, vaina, espiga y mazorca) a traves del ciclo vegetativo. Los resultados revelaron que la relacion tallo/hoja fue la variable con mayor influencia sobre la EUA. Los genotipos HV-313, H-303 y Colecta 77 tuvieron una EUA de 1.87, 2.23 y 1.4 g/kg respectivamente. La EUA fue una funcion del potencial genetico y del ciclo vegetativo.