The Northern and Central Oases of the Province of Mendoza (Argentina): water resources and sustainability challenges

International audiencePendant les dernières décennies du 20ème siècle, les oasis de Mendoza, au coeur de la diagonale aride sudaméricaine, ont connu de profondes mutations de leur modèle socio-économique, fondé sur l'agriculture et les industries agro-alimentaires. La mondialisation, Mendoza l'a connue assez brutalement : la crise économique du Mercosur des années 2000 - suivant de près celle des marchés asiatiques (1997-98) - a entrainé un afflux massif d'investissements internationaux, malheureusement localisés sur l'oasis Centre, aux dépens de l'oasis historique, l'Oasis Nord. Tandis que celle-ci subit une très forte pression démographique et industrielle entraînant une pollution marquée de l'eau d'irrigation, l'oasis Centre connaît un véritable boom économique. C'est ainsi toute la structure sociale de la province qui est bouleversée, ce qui se manifeste géographiquement par une inversion des centralités-périphéries

Effects of high versus low-quality preschool education : a longitudinal study in Mauritius

We report on a randomized controlled experiment in Mauritius by the Joint Child Health Project. This longitudinal study followed a cohort of children from different socio-economic backgrounds to examine educational outcomes among children in high and low-quality preschools. The findings show that quality of preschool education had no significant effect on children's overall educational attainment. However, academic performance of children in the experimental group was higher for children with poorly educated fathers, but lower for children with poorly educated mothers. Hence, the effects of high-quality preschool education worked in opposing directions—equalizing by compensating for the effect of father's level of education, and disequalizing by reinforcing the effect of mother's level of education

Rendimiento de grano y eficiencia en el uso del agua en maíz bajo riego complementario con agua salina

En San Luis, Argentina, el cultivo de maíz es relevante con un rendimiento medio de grano de 1.600 kg ha-1 inferior al potencial con riego complementario (14.000 kg ha-1). No siempre se dispone de agua de calidad para riego pero en la región semiárida con suelos permeables se podrían estabilizar los rendimientos con riego complementario con agua salina. El objetivo del trabajo fue determinar el rendimiento en grano y la eficiencia en el uso del agua del cultivo de maíz con distintos niveles de riego con agua salina y ertilización con nitrógeno y fósforo. Durante las campañas agrícolas 2005-06 y 2006-07 se evaluó el rendimiento de maíz con tres niveles de riego, 100% y 50% del requerimiento hídrico y secano; y 9 niveles de fertilización combinando nitrógeno y fósforo. Se regó por aspersión con agua salina con una conductividad de 4,26 dS m-1. El diseño estadístico fue anidado. Las dosis de riego fueron determinadas con datos meteorológicos históricos corregidas quincenalmente a través del contenido hídrico del suelo. El rendimiento se determinó mediante la cosecha de dos metros lineales del surco central de cada parcela, calculándose la producción de grano y la eficiencia de uso del agua. Durante el primer año con precipitaciones menores a la media la producción de los tratamientos de riego fue superior al de secano, mientras que en el segundo año con precipitaciones superiores a la media se observaron mayores rendimientos en tratamientos con 50% de riego. No se encontró respuesta a la fertilización nitrogenada ni fosforada en cuanto a rendimiento y EUA durante la primera campaña, aunque se logró estabilizar los rendimientos regando con agua salina. Durante el segundo año los mayores rendimientos se lograron con niveles de fertilización y riego medios, y los tratamientos de secano también lograron un buen desempeñoIn San Luis Province, Argentina, maize is annually cultivated, with an average grain yield of 1,600 kg ha-1, by far below of the potential yield with complementary irrigation (15,000 kg ha-1). Quality water is not always available for irrigation. However, in semiarid region with permeable soils it is possible to reach stabilize maize yields by using supplementary irrigation with saline water. This work evaluated the yield and water use efficience of maize crop cultivation under different irrigation levels with saline water and fertilization with nitrogen and phosphorus. During two growing seasons (2005-2007) evaluated maize yield with three irrigation levels: 100% and 50% of water crop requirements, and unirrigated land; and nine fertilization treatments which the combination of different levels of nitrogen and phosphorus. The crop was sprinkler irrigated with saline water,conductivity was 4.26 dS m-1. The statistic design for fertilization treatment was nested. Irrigation levels were determined on the basis of the historical data, and corrected biweekly by considering the soil water content. Grain yield was measured along two central lineal meters by plot and water use efficiency (WUE) was also measured. During the first year of the study the pricipitation was below average, the crop yield were statistically (α = 0.05) higher under irrigation than on the un-irrigated treatment. In the second year the precipitation was higher average, crop yield in treatments with 50% of irrigation was significantly higher than in the other ones. This year don’t found response to nitrogen and phosphorus fertilization about crop yield and water use efficiency, but saline water irrigation allowed stabilized yields. In second year the higher yields were achieved with average irrigation and fertilization levels, the anirrigated treatment also achieved good performance.EEA San LuisFil: Saenz, Claudio Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; ArgentinaFil: Gomez Hermida, Vanina Fernanda. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación y Desarrollo Tecnológico para la Agricultura Familiar Región Pampeana; ArgentinaFil: Frigerio, Karina Laura. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; ArgentinaFil: Morábito, José Antonio. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Terenti, Oscar Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; ArgentinaFil: Cortes, Marcela Patricia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; Argentin

Um modelo baseado em programação linear e programação de metas para análise de um sistema de produção e distribuição de suco concentrado congelado de laranja A model based on linear programming and goal programming to analyze a frozen concentrated orange juice production and distribution system

Neste trabalho apresenta-se um modelo baseado em programação linear e programação de metas para apoiar decisões no processo de mistura e na distribuição de suco concentrado congelado de laranja. Explora-se a importância das decisões do processo de mistura para a análise da logística de distribuição do suco de laranja, além das decisões de transporte e armazenagem. O modelo utiliza conceitos conhecidos da literatura de problemas de mistura e planejamento da produção com múltiplos produtos, estágios e períodos, e foi resolvido por meio da linguagem de modelagem GAMS (General Algebraic Modeling System). Um estudo de caso foi realizado numa empresa de suco de laranja localizada no interior do estado de São Paulo, e os resultados preliminares obtidos são promissores.This work proposes a model based on linear programming and goal programming to support decisions in the blending process and distribution of frozen concentrated orange juice. This study explores the importance of blending decisions for the logistic analysis of the orange juice distribution, besides transportation and storage decisions. The model utilizes well-known concepts from the literature of blending problems and multistage, multiproduct and multiperiod production planning problems, and it was solved using the GAMS (General Algebraic Modeling System) programming language. A case study was developed in an orange juice industry located in São Paulo State, and the preliminary results are promising