The residual value of phosphorus addition is described by two reactions: a quick initial reaction followed by a slower reaction over time. In this study, the residual effect of two P sources was evaluated: monopotassium phosphate (MKP) and triple superphosphate (TSP) added to soils from Ecuador and Chile with contrasting soil P retention capacity. Olsen-P extractability was measured and compared in soil samples 1, 2, 4, 8, 15, 45, 90, 180 and 360 days after the addition. The Olsen-P extracted at 24 hours after the P addition varied among soils, and extracted between 10 and 66% of the P added depending upon the soil, with lower extraction values in soils with high P retention capacity. When the source was TSP, only approximately 70% of P was extracted compared to that extracted when MKP was added. After the phosphate addition there was a clear initial effect followed by a progressive loss of Olsen-P extractability. Furthermore, over time, a state of quasi-equilibrium or a stationary state become evident in which the loss of P extractability was minimal. When the initial effect was removed, as a point that characterizes different types of soils, the loss of P extractability was similar among soils, and reflects the amount of phosphate added despite the type of fertilizer used.

En Ecuador, el sistema de educación superior ha experimentado una gran expansión tanto en número de estudiantes que aspiran obtener un título universitario como de instituciones públicas de educación superior (IPES). La mayoría de las cuales son financiadas por el estado, que históricamente ha asignado de forma imparcial los presupuestos beneficiando a IPES consideradas tradicionalmente elitistas, por su proceso de selección de estudiantes. El objetivo de la investigación fue establecer el impacto del efecto Mateo en IPES del Ecuador, durante el período 2014-2018. La metodología tuvo un diseño no experimental, descripto de desarrollo longitudinal. Un total de 26 IPES fueron analizadas en términos del presupuesto anual, eficiencia de ejecución, número de estudiantes, porcentaje destinado a la investigación y el número de publicaciones indizadas. Los datos fueron obtenidos de portales electrónicos y de la base de datos Scopus. Los resultados evidencian: 1) la mayor asignación presupuestaria a cuatro IES, sin relación al número de estudiantes o publicaciones, 2) los obstáculos financieros que afrontan las IES no elitistas para la consecución de sus planes de crecimiento, y 3) la necesidad de un cambio en esta injusta política fiscal, que no responde a principios de equidad y educación de calidad para todos

No abstract

Grafting is a common practice in cacao cultivation, but it has not been reported whether rootstock-scion combinations respond differently in terms of water transport, growth, or nutrient uptake under varying soil water availability conditions. The effects of water deficits on water potential (Ψf), basal diameter (db), root growth, chlorophyll and leaf concentrations of nitrogen (N) were evaluated in 16 rootstock-scion combinations that resulted from four rootstocks and four scion clones. Grafted seedlings were subjected to two water regimes: 21 days without irrigation (WD) and continuous irrigation (I). Under WD conditions, Ψf tended to be lower when using the EETP800 clone with the four rootstocks, indicating that this clone may have a higher rate of transpiration. The greater Ψf (p <0.05) obtained with the EET400 and EET399 rootstocks-scion combinations indicate higher water uptake capacity by the root systems of these rootstocks, which permits the maintenance of adequate transpiration rates and higher Ψf. The higher db, chlorophyll content and leaf N content obtained in the combinations of scions with the EET400 rootstock under WD impart on this rootstock a more favorable degree of adaptability for tolerating water deficits. However, this tolerance is not associated with increased root growth, which indicates that higher efficiency of water uptake is related to metabolic and physiological processes rather than a larger root surface.