Abstract. The profitability of hydropower in Costa Rica is affected by soil erosion and sedimentation in dam reservoirs, which are in turn influenced by land use, infiltration and aquifer interactions with surface water. In order to foster the provision and payment for Hydrological Environmental Services (HES), a quantitative assessment of the impact of specific land uses on the functioning of drainage-basins is required. The present paper aims to study the water balance partitioning in a volcanic coffee agroforestry microbasin (1 km 2 , steep slopes) in Costa Rica, as a first step towards evaluating sediment or contaminant loads. The main hydrological processes were monitored during one year, using flume, eddy-covariance flux tower, soil water profiles and piezometers. A new Hydro-SVAT lumped model is proposed, that balances SVAT (Soil Vegetation Atmosphere Transfer) and basin-reservoir routines. The purpose of such a coupling was to achieve a trade-off between the expected performance of ecophysiological and hydrological models, which are often employed separately and at different spatial scales, either the plot or the basin. The calibration of the model to perform streamflow yielded a Nash-Sutcliffe (NS) coefficient equal to 0.89 for the year 2009, while the Correspondence to: F. Gómez-Delgado (fgomezd@ice.go.cr) validation of the water balance partitioning was consistent with the independent measurements of actual evapotranspiration (R 2 = 0.79, energy balance closed independently), soil water content (R 2 = 0.35) and water table level (R 2 = 0.84). Eight months of data from 2010 were used to validate modelled streamflow, resulting in a NS = 0.75. An uncertainty analysis showed that the streamflow modelling was precise for nearly every time step, while a sensitivity analysis revealed which parameters mostly affected model precision, depending on the season. It was observed that 64% of the incident rainfall R flowed out of the basin as streamflow and 25% as evapotranspiration, while the remaining 11% is probably explained by deep percolation, measurement errors and/or inter-annual changes in soil and aquifer water stocks. The model indicated an interception loss equal to 4% of R, a surface runoff of 4% and an infiltration component of 92%. The modelled streamflow was constituted by 87% of baseflow originating from the aquifer, 7% of subsurface nonsaturated runoff and 6% of surface runoff. Given the low surface runoff observed under the current physical conditions (andisol) and management practices (no tillage, planted trees, bare soil kept by weeding), this agroforestry system on a volcanic soil demonstrated potential to provide valuable HES, such as a reduced superficial displacement-capacity for fertilizers, pesticides and sediments, as well as a streamflow regulation function provided by the highly efficient mechanisms Published by Copernicus Publications on behalf of the European Geosciences Union. 370 F. Gómez-Delgado et al.: Modelling hydrological behaviour of coffee agroforestry basin in Costa Rica of ...

Changes in species composition and abundance driven by land use change may alter canopy and litter characteristics of forests, and thereby modify rainfall redistribution and hydrological processes. To elucidate the interacting effects between tree species traits, forest structure and annual rainfall patterns on hydrological processes, three types of forest assemblages were selected in a semiarid forest of pine–oak in central northwest Mexico. Forest assemblages included monospecific and mixed patches of Quercus potosina and Pinus cembroides. Total precipitation, throughfall, stemflow and runoff were measured from June 2006 to July 2009. Additionally, tree and litter characteristics were measured. Forest traits played an important role differentiating volumes of each fraction among the three forest patches. Throughfall was 15% greater in Q. potosina than in the other forest patches (P < 0.01) and only occurred with rainfall events larger than 1.4 mm for all patch types, whereas Q. potosina stemflow was >20% larger compared with the other two forest patch types (P < 0.01) and occurred following rain events of at least 4.6 mm. Runoff exhibited divergences among forest patches (P > 0.05) that were related to both the litter decomposition stage and the capacity of litter bed to store water. Thus, Q. potosina litter layer exhibited the largest water holding capacity (62%) and P. cembroides (46%) the least. Hence, surface runoff for Q. potosina was seven times lower than that in P. cembroides patches. This study revealed tree trait effects on water fluxes that might have consequences on the dynamics and productivity of semiarid forests. Copyright © 2013 John Wiley & Sons, Ltd.

This study was aimed at obtaining the maximum yield per unit of water applied instead of maximizing the yield per unit of area. We therefore recommend PRD or DI as feasible irrigation options for sustainable production of cactus pear. © 2018 Society of Chemical Industry.

La variedad de arroz INIFLAR RT fue introducida a México como línea en 2005 en una generación F6, a través de los viveros internacionales de observación del fondo latinoamericano de arroz de riego (VIOFLAR-2005). Este genotipo procede de la cruza triple entre los progenitores CT10825-1-2-1-3/FEDEARROZ50//FLO2066-4P1-1P-M de los cuales se obtuvo la progenie codificada por el FLAR como FLO4621 (F1), en Palmira, Colombia. Se sembró la semilla F1 (cosecha masal) para generar la F2 en la cual se realizó una cosecha utilizando el método de pedigrí (selección de plantas individuales). Se realizaron cuatro selecciones genealógicas más, hasta obtener la F5, a ésta última selección de forma masal, se le denominó FLO4621- 2P-1-3P-3P-M. Una vez introducida a México, se evaluó la F5 en dos ciclos: 2006 y 2009 con pruebas preliminares de rendimiento en el trópico seco, posteriormente se realizaron dos ensayos más en 2011 y 2012 en el trópico seco y húmedo. En 2013 se realizó la evaluación en un Ensayo Compacto de Rendimiento (ECR), se determinó la interacción genotipo x ambiente, y un estudio de parámetros de estabilidad bajo diferentes ambientes del trópico húmedo y trópico seco. Durante 2014 se realizó la validación a nivel nacional bajo riego y temporal en el trópico húmedo y seco; además se confirmó de la calidad molinera en el laboratorio de arroz del Campo Experimental Zacatepec, Morelos y se produjo semilla básica. Se realizaron seis años de evaluación, antes de comenzar el registro de la nueva variedad, la cual obtuvo un rendimiento promedio de 7.1 t ha-1 en 2013 y 2014, una tonelada por encima del testigo nacional El Silverio, variedad más tardía. El número de registro provisional ante el SNICS es el 3103-ARZ-017-230315/C.

No abstract

No abstract

Se evaluó la producción, calidad y componentes de rendimiento de seis variedades de avena forrajera en Zacatecas. Los experimentos se establecieron en julio de 2011 y 2012 en el municipio de Monte Escobedo. El diseño experimental fue bloques completos al azar con tres repeticiones, la densidad de siembra fue 120 kg ha-1 y dosis de fertilización de 60-40-00 de N, P2O5, K. La cosecha fue en estado fisiológico lechoso-masoso. En 2011 y 2012, La variedad Saía sobresalió (P<0.05) entre cultivares en rendimiento de forraje seco con 3.7 y 5.6 ha-1, altura de planta con 119 y 120 cm, y en componentes de rendimiento acumuló la mayor (P<0.05) proporción de hoja y tallo. La variedad Karma sobresalió en proporción de espiga con 42 y 49 % (P<0.05) en 2011 y 2012, respectivamente. En proteína cruda losresultados fueron similares (P>0.05) entre variedades con un rango de 10.6 a 13.8 %. En los dos años de estudio Karma presentó las mejores características nutricionales: baja acumulación de fibra detergente neutro (51 %) y acida (33.4 y 35.3 %), valores altos en total de nutrientes digestibles (54 y 58 %), digestibilidad de la materia seca (60 y 62 %), valor relativo del forraje (110 y 113) y energía neta para lactación (1.4 y 1.34 Mcal/kg; P<0.05). Las variables asociadas de manera positiva con forraje seco fueron altura de planta (r=0.701), días a cosecha (r=0.685) y proporción de tallo (r=0.629), y negativamente con proporción de espiga (r=-0.629). En calidad nutricional Karma tuvo mejor valor forrajero. Saia es una buena alternativa para incrementar el rendimiento de forraje por hectárea.

The second largest pool of terrestrial carbon is soil CaCO 3. In addition to being an important sink of atmospheric CO 2 , soil carbonate is potentially an important source of atmospheric CO 2. The cemented form of soil carbonate-the petrocalcic horizon-develops in geomorphically stable soil in arid, semiarid, and some subhumid climates. In many of these dryland areas, such as the Chihuahuan Desert of North America, erosion has stripped away overlying soil and exhumed the petrocalcic horizon, thereby exposing it to a weathering zone above the calcification zone where it normally forms. This research tested the hypothesis that soil type 1 (eroded Aridisols with exhumed petrocalcic horizons) will emit more CO 2 than soil type 2 (noneroded Aridisols with petrocalcic horizons) or soil type 3 (Entisols formed in sandy, noncalcareous sediments). We tested this hypothesis by comparing the amount of CO 2 and the d 13 C of CO 2 released from the three soil types. Using a randomized complete block design, CO 2 emissions were measured using NaOH and soda lime traps from June 2002 to October 2003. Neither the NaOH traps nor soda lime traps detected any statistical difference in cumulative CO 2 emissions from the three soil types at the a 5 0.05 level. Moreover, the isotopic analysis of CO 2 did not match the isotopic values of pedogenic carbonate, nor were there any statistical differences (a 5 0.05) in d 13 C of CO 2 among the three soil types. We conclude, therefore, that exhumed petrocalcic horizons are not actively emitting CO 2 at a rate significantly greater than adjacent soils, and thus carbon stored in petrocalcic horizons can be considered a recalcitrant reservoir within the decadal timeframe pertinent to carbon sequestration policies.