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The runoff threshold is the amount of precipitation that exceeds the infiltration capacity of the soil and from which water begins to flow over the land surface. Its spatial variation will determine the appearance of a series of processes and risks such as soil erosion, sediment transport, water pollution or flooding, all of which are of great interest in the field of land planning and management. This article provides an update of the runoff threshold in the territorial scope of the Demarcación Hidrográfica de las Cuencas Mediterráneas Andaluzas and evaluates the spatial changes occurred between 1990 and 2018 because of land use dynamics. For this purpose, the methodology described in Regulation 5.2-IC related to surface drainage, of the Instrucción de Carreteras (Ministerio de Obras Pu'blicas y Urbanismo [MOPU], 1990; Ministerio de Fomento, 2016, 2019) was used. The results obtained show very contrasting runoff threshold values, with maximums in the western sector and minimums in the eastern sector. On the other hand, the dynamics of land use changes have led to a significant increase in impermeable surfaces and sclerophyllous vegetation, which has generated a clear reduction in runoff threshold values in different areas, mainly in the eastern region. Specifically, the former forest areas, currently occupied by sclerophyllous vegetation, stand out, with a reduction of 17 mm over an area of approximately 229.1 km2. The conversion of agricultural lands into urban areas is also noteworthy, with a decrease in their retention capacity by up to 14 mm of precipitation, covering a total area of 97.1 km2. [ABSTRACT FROM AUTHOR]

Introducción. El cultivo de palto es susceptible al estrés hídrico, durante la etapa de floración y el crecimiento inicial de los frutos. Este estrés puede ocasionar la caída prematura de los frutos y acentuar la alternancia en la producción. Objetivo. Determinar el índice de estrés hídrico del cultivo (IEHC) en tres cultivares de palto (Hass, Fuerte y Zutano) bajo diferentes condiciones de riego, mediante el empleo de termografía infrarroja. Materiales y métodos. El estudio se realizó en la temporada de otoño del 2023, en la Estación Experimental Agraria Canaán, Ayacucho, Perú. Se seleccionaron 170 árboles de palto de cuatro años en fase reproductiva. Se llevaron a cabo cinco evaluaciones bajo diferentes condiciones de riego, donde se recopiló información después de 14 y 7 días sin riego (SR-14d y SR-7d) y 12, 2 y 1 hora posterior al riego (DR-12h, DR-2h y DR-1h, respectivamente). Se registró la temperatura de las hojas (Th), la conductancia estomática (gs), la humedad del suelo (θ) y IEHC. Resultados. Los tres cultivares evaluados en este estudio presentaron diferencias significativas de la Th según manejo del riego. Estas variaciones, influenciadas por la temperatura y humedad ambiental, establecieron umbrales de estrés que definieron el IEHC en un rango de 0,34 a 0,96. Al relacionar el IEHC con la gs y θ se obtuvieron un R de 0,51 y 0,61, respectivamente. El cultivar Zutano mostró el valor más alto de IEHC en períodos prolongados de restricción de riego, pero tuvo una baja capacidad para reducir estos valores tras la rehidratación, a diferencia de los otros cultivares. Conclusiones. La termografía infrarroja es una herramienta crucial para evaluar el estado hídrico y las respuestas de los cultivares de palto a diferentes condiciones de riego y ambiente, con la Th y el IEHC como indicadores que responden a las condiciones ambientales.

El cultivo de zapallo Cucurbita moschata Duchesne ha cobrado interés por el alto valor nutricional del fruto; sin embargo, en las regiones productoras de Colombia, el riego para el zapallo es una labor empírica, dado que en el país no existen estudios que asocien el efecto del riego sobre la producción del fruto. Por lo tanto, se estudió el efecto del régimen de riego sobre la producción de tres cultivares de zapallo. Se aplicaron cinco láminas de riego con base en: Kc del cultivo (0,4; 0,6; 0,8; 1,0 y 1,2) a tres cultivares de Zapallo: UnapaL-Abanico-75 (A75), Unapal-Bolo Verde (Bv) y Unapal-Dorado (Dr), con ocho repeticiones, para un total de 96 plantas. El diseño experimental fue parcelas divididas, donde la parcela principal fue el tratamiento de riego y la subparcela, los cultivares. Los caracteres frutos por planta (FPP), peso promedio del fruto (PPF), producción por planta (PPP), materia seca (MS) y espesor de pared de pulpa (EP) presentaron diferencias altamente significativas, de acuerdo con el régimen de riego, asociadas, en modo positivo, con nivel de Kc más alto (1,2).

The research was conducted at the National Institute of Agricultural Sciences located in Mayabeque province, Cuba, with the aim of determining the response of bean crops to controlled deficit irrigation applied at different stages of their biological cycle. The study was carried out during two planting seasons (January and October 2021) under semi-controlled conditions. Seeds of the Triunfo 70 cultivar were sown in concrete containers, and three irrigation suspension periods of 15 days were studied: during the vegetative growth stage (VG), flowering stage (FS), and grain filling stage (GFS), along with a control group irrigated at 100% of the ETc. After the irrigation suspensions, soil moisture, growth indicators, and yield components were evaluated. In VG during the second experiment, it reduced stem length, leaf number, and leaf area. Above-ground dry mass decreased in both experiments, as well as the mass of 100 grains and grams per plant. In FS, it reduced stem length, relative chlorophyll content (RCC), mass of 100 grains, and yield in grams per plant, while in GFS, only the RCC was affected. Based on the results, it can be concluded that the grain filling stage was the least sensitive to water deficiency, causing the least impact on yield. [ABSTRACT FROM AUTHOR]

Summary: Tropical forest function is of global significance to climate change responses, and critically determined by water availability patterns. Groundwater is tightly related to soil water through the water table depth (WT), but historically neglected in ecological studies. Shallow WT forests (WT < 5 m) are underrepresented in forest research networks and absent in eddy flux measurements, although they represent c. 50% of the Amazon and are expected to respond differently to global‐change‐related droughts. We review WT patterns and consequences for plants, emerging results, and advance a conceptual model integrating environment and trait distributions to predict climate change effects. Shallow WT forests have a distinct species composition, with more resource‐acquisitive and hydrologically vulnerable trees, shorter canopies and lower biomass than deep WT forests. During 'normal' climatic years, shallow WT forests have higher mortality and lower productivity than deep WT forests, but during moderate droughts mortality is buffered and productivity increases. However, during severe drought, shallow WT forests may be more sensitive due to shallow roots and drought‐intolerant traits. Our evidence supports the hypothesis of neglected shallow WT forests being resilient to moderate drought, challenging the prevailing view of widespread negative effects of climate change on Amazonian forests that ignores WT gradients, but predicts they could collapse under very strong droughts.See also the Commentary on this article by Chitra-Tarak & Warren 237: 703–706. [ABSTRACT FROM AUTHOR]

Objetivo: Establecer un modelo dinámico del sistema intensidad de precipitación de agua – porosidad del suelo y velocidad de infiltración a fin de medir la profundidad de infiltración de agua y de humedad en el suelo que producen el deslizamiento. Metodología: Aplicando Dinámica de Sistemas se desarrolló un diagrama causal de las variables geotécnicas de dos muestras de suelo de sitios afectados por fenómenos de remoción en masa en Pamplona (Colombia); el modelo fue implementado con el software Stella v9. Resultados: Los resultados de simulación muestran la variación de profundidad de suelo a saturar para alcanzar el límite líquido o la falla debido a esfuerzo cortante. Conclusiones: La relación entre el fenómeno de remoción en masa y precipitación no coincide con el imaginario colectivo actual sino por un conjunto de valores característico de precipitación para cada tipo de suelo. Financiamiento: La investigación fue financiada con recursos propios de los autores.

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El objetivo de este estudio fue evaluar el uso de residuos de cosecha de maíz como cobertura vegetal y su impacto en el contenido de humedad del suelo y el establecimiento, desarrollo y productividad del pasto buffel (Cenchrus ciliaris L). Se usó un diseño de bloques al azar con tres repeticiones. Los tratamientos fueron: siembra de 10 kg ha-1 de semilla de pasto buffel (Sp); cobertura vegetal en suelo con 10 t ha-1 de residuos de cosecha de maíz (Cv); combinación Sp + Cv; y testigo (sin siembra de pasto y sin cobertura vegetal). El tratamiento Sp + Cv mantuvo un mayor contenido de humedad en el suelo (P≤0.05), con 13.8 % contra 10.6 % del testigo. En consecuencia, el número de plantas de pasto m-2, cobertura de pasto buffel, altura de la planta, índice de clorofila y producción de biomasa seca, tuvieron una tendencia de mejor respuesta, con valores de 518.5 plantas m-2, 51.23 %, 31.8 cm, 162 y 167.8 g m-2, respectivamente, con una tendencia de respuesta estadísticamente similar este tratamiento al aplicarse de manera separada (Cv y Sp). La fotosíntesis (µmol s-2s-1), conductancia estomática, transpiración (mmol H2O m-2 s-1) y uso eficiente del agua, no fueron afectadas por ninguno de los tratamientos de este estudio, con respuesta equivalente a la del testigo. [ABSTRACT FROM AUTHOR]

Methodological criteria for data quality control with geophysical range and spectrum consistency were evaluated, establishing flags and quality indicators for soil moisture data records, in a range of depths between 10, 30, and 50 cm, from automatic agro-meteorological stations located in the most important agricultural regions of Colombia. Data for analysis were collected from 105 stations of the IDEAM network, in an observation window from 2001-2020. The results showed that 40.3% of the soil moisture data were of good quality, 12.9% were questionable due to spectrum flags, 14.3% were questionable due to geophysical range and 32% were erroneous because the values were not possible and/or missing. The depth closest to the surface had the highest number of quality flags, suggesting that the soil layer has the highest error detection rate associated with soil moisture condition recording; the most common quality flag was C02: "Soil moisture >60% & ≤100%", detected in 93% of the sensors, and the second most frequent flag was C01: "Soil moisture ≥0% & <3%". It was concluded that the proposed methodology provides highly satisfactory results in the detection of anomalous soil moisture records, in order to make adjustments to the environmental conditions of Colombia. [ABSTRACT FROM AUTHOR]

El objetivo de este estudio fue evaluar el uso de residuos de cosecha de maíz como cobertura vegetal y su impacto en el contenido de humedad del suelo y el establecimiento, desarrollo y productividad del pasto buffel (Cenchrus ciliaris L). Se usó un diseño de bloques al azar con tres repeticiones. Los tratamientos fueron: siembra de 10 kg ha-1 de semilla de pasto buffel (Sp); cobertura vegetal en suelo con 10 t ha-1 de residuos de cosecha de maíz (Cv); combinación Sp + Cv; y testigo (sin siembra de pasto y sin cobertura vegetal). El tratamiento Sp + Cv mantuvo un mayor contenido de humedad en el suelo (P≤0.05), con 13.8 % contra 10.6 % del testigo. En consecuencia, el número de plantas de pasto m-2, cobertura de pasto buffel, altura de la planta, índice de clorofila y producción de biomasa seca, tuvieron una tendencia de mejor respuesta, con valores de 518.5 plantas m-2, 51.23 %, 31.8 cm, 162 y 167.8 g m-2, respectivamente, con una tendencia de respuesta estadísticamente similar este tratamiento al aplicarse de manera separada (Cv y Sp). La fotosíntesis (µmol s-2s-1), conductancia estomática, transpiración (mmol H2O m-2 s-1) y uso eficiente del agua, no fueron afectadas por ninguno de los tratamientos de este estudio, con respuesta equivalente a la del testigo.

The development of the wet bulb under drip irrigation in sand covered soils presents a different behavior from that observed under homogeneous soils. The presence of a very active crop also imposes a series of variations that have not been fully characterized. The aim of this work is to present the data acquisition methodology and the necessary precautions to obtain a model that accurately defines the evolution of moisture in wet bulbs generated in sanded soils characteristic of intensive horticultural crops. The procedure for collecting and processing moisture data in stratified soils has been defined. The soil and permeability curve has been adjusted experimentally for each material. It has been proved that the Hydrus-3D model can reproduce the behavior of a sand covered soils and it has been possible to verify that the predictions are adequate to what has been observed in the field.

A pesar de que hoy en día la identificación y caracterización de sequías sigue siendo un proceso no estandarizado, lo más habitual es utilizar índices como el SPI o el SPEI entre otros. En este estudio se han analizado sequías históricas, no solo a través de los índices SPI y SPEI, sino también a través del índice SSMI, con series de humedad de suelo simuladas con el modelo hidrológico Variable Infiltration Capacity (VIC). El objetivo es mostrar la importancia de considerar la humedad del suelo en estudios de sequías. La ocurrencia de las sequías se ha determinado a través de los impactos económicos y agrícolas generados, y no únicamente a través del déficit hídrico. Se puede concluir que la humedad del suelo es un factor determinante en el estudio del impacto de la sequía en la producción de cereales y especies de grano grueso, pero no en las pérdidas económicas inducidas.

The article presents the results of a study conducted in Cuba on the flooding time that maize crops can withstand without affecting their yield. The Tuzón variety was used in pots with Red Ferralitic soil. The results showed that as the flooding time increased, there was a reduction in maize grain production, reaching a 50% loss with 70 hours of excess moisture. Additionally, the plants experienced losses in weight and length of the cobs during the flooding. This study is relevant for the design of drainage systems in maize crops. [Extracted from the article]

The objective of this study was to evaluate soil moisture in four environments: native forest (Cerrado native de Mata Atlântica), pasture, pine plantation and cultivated soil. For analysis of humidity and water content in the soil, it was necessary to collect 20 undeformed samples monthly for each type of cover, in five depth bands 0-5 cm, 5-30 cm, 30-50 cm, 50-80 cm and 80-100 cm. The study revealed that the superficial strip has the lowest moisture percentage of the entire soil profile, while the deepest stratum 80 to 100 cm presented the highest moisture values. On the other hand, the soil covered by the native Cerrado of Mata Atlântica presented the highest percentage of moisture and the highest content of water stored in the soil; therefore, it is concluded that the surface strip is the one that presents the greatest variability in soil moisture because it is located in the evaporable zone or with the greatest exposure to solar radiation; consequently, as the depth increases, the greater the storage of water in the soil; On the other hand, the coverage analogous to a primary forest presents the highest percentage of humidity and water storage in the soil. [ABSTRACT FROM AUTHOR]

El presente estudio se desarrolló en la parte norte del Perú, en la cuenca del río Jequetepeque, cordillera occidental de los Andes con dirección al Océano Pacífico. En su cauce principal se encuentra el embalse Gallito Ciego, fuente de agua para la actividad agrícola en el valle costeño del Jequetepeque y la generación de energía eléctrica; sin embargo las deficiencias de agua y el desconocimiento de la importancia de las cabeceras de cuenca como aporte importante de agua, nos permite estudiar cómo influye la geomorfología y la meteorización en la humedad de los suelos y las recargas de agua a lo largo de la cabecera de cuenca del río Jequetepeque. Como parte de la metodología se generó un sistema integrado de parámetros físicos como: la geomorfológica, la pendiente, el intemperismo, la precipitación, escorrentía, humedad y vegetación. Los resultados muestran que la geomorfología es variable influyente en la humedad; así mismo la existencia de un fuerte intemperismo en la parte norte de la cuenca respecto a la parte sur, influye en la conservación de humedad del 33.87% y la generación de un bosque húmedo con plantas de aliso. En consecuencia, la humedad y recarga de aguas subterráneas, esta explicado por la topografía, la meteorización de las rocas, argumentando también que son evento más trascendente a nivel de cabecera norte de la cuenca del río Jequetepeque.

Biological soil crust (BSC) plays an important role in numerous functional aspects of arid and semi-arid ecosystems. Particularly, it plays a decisive role in offering suitable microsites for establishment and development of vascular plant species. BSC would be important to assist the ecological restoration of land degraded by use and increase the development of native communities with ecological value. The objective of this work was to examine the emergence and establishment of seedlings of Pappophorum caespitosum and Nassella longiglumis, two native grass species, in relation to the presence of BSC and water availability. The results obtained allow us to observe that the differences in the emergence and establishment of the herbaceous species studied were related with the availability of water and not with the coverage of BSC. In order to carry out ecological restoration works that include CBS and native forage species, aspects related to precipitation and temperature regimes should be taken into account. The results obtained do not allow us to state whether CBS has positive or negative effect on the establishment of seedlings of these species, but they do allow us to know their behavior under different soil water conditions. [ABSTRACT FROM AUTHOR]

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Background. The CO2 emission flow from the soil, known as soil respiration, is an important pathway in the global carbon cycle. Objective. Thus, the objective of the present was to determine the variation of CO2 emissions according to a) different management before, during and after grazing by cattle; b) influence of environmental and soil factors on emissions, as well as c) adjust a model and assess its sensitivity to dimension the applicability in soil respiration behavior. Methodology. The soil respiration was measured every 30 min for 312 hours followed by a closed dynamic chamber of known volume placed on the floor, integrated with an infrared gas analyzer (Model 8100-104). Results. The results indicate that the total emissions in each management were 228, 128 and 241 kg CO2 ha-1 day-1 in an agroforestry system with fruit trees before, during and after grazing, respectively. The ambient temperature influences the respiration of the soil in the three ways. While soil moisture affects only during and after grazing. Implications. Since the results are limited, it is important to evaluate and analyze for long periods of time to understand the behavior of the R in agroforestry systems. Conclusion. In the sensitivity analysis, the increase of 2 ° C and 20% in variables such as precipitation, soil temperature and soil moisture would favor the increase of the CO2 flow from the soil to the atmosphere.

Para evaluar el efecto de los riegos presurizados sobre suelos bananeros se seleccionaron cuatro bloques, uno de ellos influenciado por un sistema de riego subfoliar y otro influenciado por un sistema de riego suprafoliar, completándolo condos bloques asociados con Kudzu (Pueraria phaseoloides Benth) de iguales sistemas de riego. El efecto de los sistemas de riego se evaluó sobre el perfil del suelo en estratos de 10cm hasta los 50 cm de profundidad, determinando en cada estratola densidad real, porcentaje de humedad, densidad aparente, resistencia a la penetración y porcentaje de porosidad, además del índice de estabilidad estructural y el de encostramiento. Los valores obtenidos indican que para ambos sistemas de riego la capa con más influencia fue la 10-20 cm y observándose un menor efecto en los bloques asociados con Kudzu, los cuales no tuvieron índices de formación de costras superficiales. Palabras clave: Sistemas de riego, porosidad, humedad del suelo, densidad aparente, banano.

The aim of this study is to estimate and map soil moisture (SM) from Cosmo-Skymed (X band) images acquired over an agricultural basin located in the center of the province of Buenos Aires, Argentina (Latitude: 37oS; Longitude: 60oW approximately). The adopted approach is empirical, with a correlation between backscattering coefficient (-0) and soil moisture (SM) measures, obtained simultaneously with a satellite pass. Surface (0 to 10 cm) soil moisture was measured by means of the gravimetric method in 15 agricultural parcels (sites). The linear relation between radar signal backscattering (0) and field measured SM [SM(%) = b+a.0(dB)] shows diverse coefficients and adjustments (r2), depending on orbit direction and polarization (from r² = 0, 28 for VV Ascending to r² = 0, 69 for HH Descending). Using corresponding relation equations, images were translated from 0 into SM (%), obtaining the SM maps (for each polarization and orbit pass). Cross-validation between measured and calculated SM was performed, computing the Root Mean Square Error (RMSE) and Normalized Mean Square Error (NMSE). Better results were obtained from Descending images, with 6,3% < RMSE < 6,9% and 1,6 < NMSE < 2,0 %). Results are compared with other experiences, and future expectations are outlined. [ABSTRACT FROM AUTHOR]

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El Parque Nacional Torres del Paine (PNTP) se caracteriza por ser un área geográfica representativa de los ecosistemas del mundo, al contener una alta belleza paisajística y amplia diversidad de ecosistemas. El objetivo de este trabajo es analizar las tendencias espacio temporales de la vegetación en el PNTP mediante el uso de imágenes remo­tas de la plataforma Landsat, del sensor “Moderate Resolution Imaging Spectroradiometer” (MODIS), correspondientes al producto MOD13A3, los mapas de cobertura de superficie Global Land Cover Maps del ESA/CCI del año 2005 y 2010 y el mapa de cobertura de suelo de Chile continental del 2014. Además, se utilizaron los productos de “Soil Moisture and Ocean Salinity” (SMOS), y datos meteorológicos de la estación meteorológica Torres del Paine para analizar las condiciones ambientales que presentó el parque mientras ocurría el incendio de los años 2011-2012. Para determinar la magnitud de los cambios de la vegetación afectada por incendio del PNTP se realizó un análisis no paramétrico de la tendencia del índice “Normalized Difference Vegetacion Index” (NDVI) de MODIS en el periodo 2002 a 2016 y el índice “Normalized Burn Ratio” (NBR) para los incendios de los años 2005 y 2011-2012. Los resultados muestran que los incendios 2005 y 2011-2012 afectaron a más de 30.000 hectáreas del Parque Nacional, siendo las coberturas de “Matorral” y “Bosque” las más afectadas debido a su alto nivel de severidad y su regeneración menor al 56% de la superficie afectada. En cuanto a la humedad de suelo esta no supera los 20% m3m–3 antes del incendio y las precipitaciones no superan los 101 mm durante los días de incendio lo que se relaciona con un aumento en las probabilidades de propagación del incendio. En este trabajo se evidencia que la teledetección puede ser utilizada en la gestión de incendios y así resguardar los parques nacionales con el fin de preservar y conservar la flora, fauna y belleza paisajística de Chile.

El objetivo del presente estudio fue determinar la influencia del contenido de humedad del suelo, la temperatura del aire, la humedad relativa y la precipitación sobre el potencial hídrico xilemático (Ψ) de cuatro especies arbustivas nativas (Condalia hookeri, Cordia boissieri, Prosopis laevigata y Celtis pallida) del noreste de México. Las mediciones del Ψ se realizaron a intervalos de 15 días entre febrero 21 y junio 30 de 2017, en cinco plantas de cada especie a las 06:00 h y 14:00 h. En el periodo más húmedo, el Ψ a las 06:00 h varió de -0.67 (C. pallida) a -0.96 MPa (C. hookeri); en cambio, en el periodo más seco, el Ψ a las 06:00 h fluctuó de -1.52 (P. laevigata) a -2.92 MPa (C. hookeri). En tanto, a las 14:00 h, C. pallida y C. hookeri presentaron el mayor (-1.07 MPa) y menor (-3.10 MPa) valor, para los periodos húmedos y secos respectivamente. El Ψ a las 06:00 h y la precipitación mostraron correlaciones positivas con el Ψ de las 14:00 h; mientras que el contenido de agua en el suelo a diferentes profundidades con los valores de los Ψ a las 06:00 h fue débil. Dado que P. laevigata y C. pallida mantuvieron altos valores en el Ψ a las 06:00 h y 14:00 h bajo condiciones de estrés hídrico, estas especies pueden ser consideradas como especies tolerantes a la sequía.

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The tomato crop, for its biological benefits, is an excellent model for basic and applied research programs. In addition, due to its nutritional properties it has reached a considerably high popularity worldwide. On the other hand, the drought stress currently aggravated by global warming limits the crops productivity throughout the world. Therefore, it is essential to obtain cultivars with greater water use efficiency. The work consisted to evaluating the behavior of five tomato lines under field conditions and cultivated in two irrigation variants. The seedlings were planted in blocks of 1000 m2 each in a leached red ferralitic soil. Two soil moisture treatments (T1 and T2) were established, which were differentiated by their arrangement of the drip irrigation lines. T1 where the humidity was maintained in a range between 22 % and 36 % (well supplied) and T2 where the humidity was between 14 and 22 % during the experiment time (stress treatment). Evaluations of Volumetric Soil Water Content (CVA) and stomatal conductance (gs) were made at 23, 30, 39, 44 and 51 DDT and the yield and its components. The results showed a differentiated effect of the treatments on soil moisture, which induced significant differences of the gs in favor of the plants cultivated in T1. The decrease of the irrigation applied to the plants of the different lines cultivated with T2, in most of the cases did not have a negative effect on the yield and their components. [ABSTRACT FROM AUTHOR]

Coffee cultivation depends on water supplied by rain or irrigation, which, in turn, affect productivity and harvest distribution. Knowing the influence of plant spacing on the behavior of soil moisture and water consumption, is likely to determine a crop's planting density, fertilization and planting times, all based on regional water availability. In this context, the study was conducted at Naranjal Experimental Station, municipality of Chinchiná (Caldas, Colombia) at 04° 58' N, 75° 39' W; 1,381 m a.s.l., aimed to describe moisture performance in a coffee plantation established on an Andisol, under three planting densities. This was done by estimating the evapotranspiration (ETo) and assessing crop evapotranspiration (ETc). Soil moisture was measured with a capacitance probe equipped with sensors spaced at 10, 20, 30, 40, 60 and 100 cm. Moisture content in the soil profile varied with planting density and from dry to humid periods. ETo and ETc were observed to be influenced by weather conditions, which determined higher values during the dry season and lower ones in the rainy season. Although planting density was found to affect hydraulic soil properties, sufficient water supply for the plants along both humid and dry seasons was stabilized by the water storage capacity that characterizes Andisols. The capacitance probe constitutes an effective tool for studying water performance in soils with coffee vocation in Colombia, especially when they are sensitive to the limitations imposed by water deficit resulting, in turn, from current or future climate variability. [ABSTRACT FROM AUTHOR]

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An experiment on rose (Rosa sp.) cv. Freedom was performed in a greenhouse on the Bogota Plateau, Colombia, to identify an efficient irrigation regime for this crop. The tested treatments were based on three irrigation doses, applying different fractions of the estimated crop evapotranspiration (ETc), calculated using a class A evaporation tank: i) 100% ETc (ETc100), ii) 80% ETc (ETc80) and iii) 70% ETc (ETc70). During the entire experimental period, from mid-May to early September, the crop had a constant production of floral stems. In all of the irrigation treatments, the soil and plant water status were monitored using tensiometers and the midday stem water potential, respectively (ystem). In the fully irrigated roses, the actual water use was determined using a drainage lysimeter in order to obtain the local crop coefficients (Kc) by means of a water balance. From June to August, the obtained monthly Kc values varied between 1.10 and 1.26. Compared to the ETc100 treatment, 14.5 and 21.8% less water was applied in treatments ETc80 and ETc70, respectively. Despite this fact, no statistically significant differences were found among the treatments for rose production or quality. Finally, in the more irrigated roses, tight relationships between the stem water potential and vapor pressure deficit were obtained. The reported base-line equations can be used for predicting the optimum rose plant water status, depending on the environmental conditions. Overall, the reported results can be used for an efficient irritation schedule for rose crops under greenhouse conditions, using the local Kc and direct determinations of plant water status corrected for the evaporative demand.

The study discuss about the soil moisture estimation using dual polarimetric RISAT-1. The semiempirical approach of Modified Dubois Model (MDM) derived by (SrinivasaRao 2013) is worked out using (σ°HH) and (σ°HV) for soil moisture estimation using dual polarimetric backscattering image. IRS LISS IV data have been used to analyze the site suitability of different land use/cover types. The retrieval of backscattering coefficient values (σ°) from SAR is the common principle factor for soil moisture estimation. The surface roughness were measured in the selected sample location, for which the same backscattering values derived from the SAR is linearly correlated showing r2 = 0.93. The estimated surface roughness is used for retrieval of dielectric constant using MDM. The dielectric constant derived from MDM in combination with the Topps model proposed by (Topp 1980), is used to derive satellite based soil moisture estimation. Linear regression analysis was performed and the soil moisture derived from SAR are well correlated with the volumetric soil moisture showing value of r2 = 0.63. [ABSTRACT FROM AUTHOR]

En el suelo de Quíbor crecen de manera discon - tinua unas costras constituidas por líquenes, briofitas y cia - nobacterias. El propósito de esta investigación es identificar variaciones en el comportamiento de algunas propiedades edáficas al comparar muestras del suelo con y sin costra. Se trata de una investigación de campo desarrollada en tres fa - ses: la primera, denominada de Campo , con el fin de recolectar muestras de suelo con apoyo en la tabla de dígitos aleatorios y a partir de dos transectas longitudinales, sobre éstas se em - pleó cada diez metros una cuadrata cuadrada de 25 x 25 cm; la segunda fase, laboratorio , en la cual se determinaron las propiedades del suelo: a) física como el %humedad; b) químicas como la salinidad, pH, Conductividad Eléctrica (C.E) y Carbono Orgánico (CO), y c) bioquímicas, entre ellas la Materia Orgánica (MO) y Dióxido de carbono (CO 2 ) desprendido; la tercera fase, de análisis estadístico, se empleó la prueba t , a fin de identificar variaciones significativas entre ambos grupos muestrales. Se concluye que la presencia de la costra en la superficie del suelo aumenta la actividad me - tabólica, el CO y la MO. En cuanto al pH, C.E, salinidad y %H no se registraron variaciones significativas.

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)