Search

Climate change has led to various adverse consequences, with natural disasters being one of the most striking outcomes. Natural disasters negatively impact life, causing significant disruptions to the ecosystem. Prompt identification of affected areas and initiation of the rehabilitation process are imperative to address the disturbances in the ecosystem. Satellite imagery is employed for the rapid and cost-effective detection of damages caused by natural disasters. In this conducted study, the outputs of climate change wildfire, forest change detection, and drought analysis, have been examined, all of which worsens the impacts on the ecosystem. The analysis of drought involved using MODIS data, while Sentinel-2A satellite images were utilized to identify wildfire areas and changes in forested regions caused by windthrow. The research focused on Ganja, Azerbaijan, as the area for drought analysis. The driest June between 2005 and 2018 was assessed using the Vegetation Condition Index (VCI) in conjunction with data from the National Centers for Environmental Information (NOAA). At the Düzce Tatlıdere Forest Management Directorate, the Normalized Difference Red Edge Index (NDRE) was utilized between the years 2018 and 2019 to detect the changes occurring in forested areas due to windthrow. The NDRE synthetic band was added to satellite images for the years 2018 and 2019, and a Random Forest (RF) algorithm was employed to classify the data. The classification results were evaluated using Total Accuracy and Kappa statistics. The study includes the detection of the Normalized Burn Ratio (NBR) applied to determine the extent of the wildfire that occurred in the Solquca village of the Qabala region in Azerbaijan in 2021. According to the analysis of the VCI and NOAA, June 2014 was identified as the driest month in Ganja. In the Tatlıdere region, the analysis indicated that 4.22 hectares experienced reforestation, while 24 hectares experienced deforestation. The NBR analysis has revealed that ~1007 hectares of land were burned in the Solquca village of Qabala. The analyses conducted provide information regarding the use of satellite imagery in relation to changes in forest areas due to drought, wildfire, and windthrow. [ABSTRACT FROM AUTHOR]

La cuenca del humedal La Bramadora, localizada en el municipio de Sopetrán, Antioquia, Colombia, está sometida a un régimen de torrencialidad manifestado a través de la formación de coluvios que se acumulan en las partes bajas de las laderas y el arrastre de materiales finos que van a los cauces y lentamente al humedal hasta constituir en él una secuencia de 950 metros de capas de arcillas y limos que se intercalan con capas turbosas, microtefras y paleosuelos. La tasa de sedimentación media (1cm/año), representa un periodo de acumulación por erosión pluvial, entre 2022 y 1455 años calendario. Este registro sedimentario guarda evidencias de eventos extremos de precipitación que podrían ser correlacionados con explosiones volcánicas y/o, con cambios climáticos globales y locales ocurridos en fechas históricas. La señal de Au y S, los fragmentos de matriz de rocas volcánicas y los vidrios volcánicos están relacionados a las actividades volcánicas del Pinatubo en 1991, Quizapu en 1932, Tambora en 1815, Ruíz en 1805, Huaynaputina en 1600 y Ruíz en 1595. Otras variables geoquímicas muestran más relación con eventos de precipitación (Niña) y de sequía (Niño) registrados en Colombia, en este lapso. Los dos picos coincidentes en las curvas de S y Au, así como la persistencia en la tasa de sedimentación, fueron contundentes para definir en tiempo calendario, la estratigrafía, y precisar los eventos extremos de precipitación y escorrentía en la cuenca; el primero de S coincide con excesos en la pluviosidad global de 1816, ocasionados por la explosión del Tambora en 1815, y sus inyecciones de S a la atmósfera; el segundo, con la explosión del Huaynaputina en 1600.

Due to the urban environment urban trees must deal with drier and hotter than in rural areas. Knowing the water consumption of each species and the indicators of water deficit is useful to decide the frequency and volume of irrigation and to select species according to the microclimate of the location. To determine approximately the irrigation frequency and to identify physiological variables that indicate water stress, it was carried out an experiment in which five tropical species (Citharexylum montanum M., Citharexylum sulcatum M., Caesalpinia spinosa K., Inga edulis M. and Retrophyllum rospigliosii P.) were subjected to water deficit. After a month of planting, eight trees per species were subjected to four treatments: control treatment (volumetric water content higher than 45% (TC)), the volumetric water content of 20% (VM20), fifteen and thirty days after the soil had reached VM20 (T15 and T30, respectively). In trees with similar height, it was found that the descending order of water consumption was I. edulis, C. montanum, C. spinosa, C. sulcatum, R. rospigliosii and that the best indicator of water deficit was the stem water potential. In general, volumetric moisture of soil of 20% was a suitable threshold to decide when irrigating regardless of the species. Deeming the effect of the treatments on the growth of the assessed species, T30 diminished severely the growth by 50% in comparison to the control, except for C. sulcatum in which there were no significant differences. [ABSTRACT FROM AUTHOR]

The La Bramadora wetland basin, located in the municipality of Sopetrán, Antioquia, Colombia, is subject to a torrential regime manifested through the formation of colluvium that accumulates in the lower parts of the slopes and the dragging of fine materials that go to the riverbeds and slowly to the wetland until it constitutes a 950-meter sequence of layers of clays and silts that are interspersed with peaty layers, microtephras, and paleosols. The average sedimentation rate (1cm/year) represents a period of accumulation by pluvial erosion, between 2022 and 1455 calendar years. This sedimentary record holds evidence of extreme precipitation events that could be correlated with volcanic explosions and/or with global and local climate changes that occurred on historical dates. The Au and S signal, the volcanic rock matrix fragments and the volcanic glass are related to the volcanic activities of Pinatubo in 1991, Quizapu in 1932, Tambora in 1815, Ruíz in 1805, Huaynaputina in 1600 and Ruíz in 1595. Others Geochemical variables show more relationship with precipitation (La Niña) and drought (El Niño) events registered in Colombia, in this period. The two coincident peaks in the S and Au curves, as well as the persistence in the sedimentation rate, were conclusive to define the stratigraphy in calendar time, and to specify the extreme events of precipitation and runoff in the basin; the first of S coincides with excesses in global rainfall in 1816, caused by the Tambora explosion in 1815, and its injections of S into the atmosphere; the second, with the explosion of Huaynaputina in 1600. [ABSTRACT FROM AUTHOR]

Copyright of Agronomía Colombiana is the property of Universidad Nacional de Colombia 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.)

The genetic improvement of any breeding population largely depends upon the magnitude of genetic variability present. This study was carried out to estimate parameters of the genetic variation among 13 quantitative traits of bread wheat evaluated at INRAA-Setif institute (Algeria) during the 2020--2021 crop season in a rainfed environment. 34 genotypes including four control checks were planted in a randomized complete block design with three replications. Genotypes showed significant variations for almost all the studied traits. Proline content, spikes weight, and grain yield exhibited a high genotypic coefficient of variation along with moderate to high heritability coupled with a high genetic gain, suggesting the implication of additive gene action. The number of spikes, spikes weight, and thousand kernel weight were significantly and positively correlated with grain yield at both phenotypic and genotypic levels. Path analysis results showed that spikes weight is an important route through which most of the measured traits influenced indirectly grain yield. Lines L1, L20, L28, L16, and L18 exhibited a sizeable grain yield advantage, which suggests they are potential candidates for future release and could be incorporated into the wheat breeding programs as parents to improve yield in the rainfed environments of Algeria. [ABSTRACT FROM AUTHOR]

Drought is a natural phenomenon that occurs frequently and has some adverse effects on the ecosystem and humanity. Determination of drought beforehand is vital for optimal management of water resources. Many different methods have been developed to detect drought. Sequential association analysis is used for the data series analysis containing time information and is one of the methods used to determine the drought. A correlation can be established between the values taken by the data at different times when determining association rules with this method. The primary purpose of this study is to determine the sequential association patterns between precipitation and climate oscillation index for Aras Basin. The Aras basin is a region where irrigation and animal husbandry are common. Today, many dams and hydroelectric power plants, together with the increasing population, meet the water and energy needs. A possible drought event in this region will adversely affect the living things in the basin. Therefore, the study focused on this basin. Finding sequential associations between precipitation and climate oscillation index can determine the temporal correlations between these parameters and specifically detect drought. The MOWCATL (Minimal Occurrences with Constraints and Time Lags) algorithm was used to detect sequential associations, and the J-measure was used to evaluate the patterns in the study. Sequential association patterns were determined by applying this method to the precipitation data obtained from 6 meteorology stations in the Aras basin. AO (Arctic Oscillation) Index, MEI (Multivariate ENSO) Index, NAO (North Atlantic Oscillation) Index, Oceanic Niño Index (ONI), PDO (Pacific Decadal Oscillation) Index, PNA (Pacific/North American), and SOI (Southern Oscillation Index), followed by the 1, 3, 6 and 12-month Agricultural Standardized Precipitation Index (a-SPI) were used in sequential association. The study results revealed that the antecedent parameters were ineffective in detecting arid conditions in Ardahan and Doğubeyazıt stations, and they were influential on drought conditions, especially in a-SPI-3 and a-SPI-12 month periods at other stations. Although the altitude and geographical features are different, similar climatic patterns have been detected in some stations. As a result, it has been determined that climatic oscillations generally bring about typical situations in terms of drought for the Aras Basin. [ABSTRACT FROM AUTHOR]

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia 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.)

This study aimed at evaluating the expected gains from selection obtained based upon direct, indirect, and index-based selection in a set of 599 bread wheat lines. The experiment was carried out at the experimental field of INRAA institute, Setif research unit (Algeria), in a Federer augmented block design including three controls. A wide range of genetic variability was observed among lines for the eleven traits assessed. The results indicated that index-based selection and selection based on grain yield expressed higher expected genetic gain than direct and indirect mono-trait-based selection. The best 15 selected lines exhibited higher grain yield than the control varieties, and they were clustered in three groups that contrasted mainly for the fIag-leaf area, thousand-kernel weight, biomass, and harvest index. The index-based selection appears as a useful tool for the rapid selection of early filial generations, enriching selected breeding materials with desirable alleles and reducing the number of years required to combine these traits in elite varieties. [ABSTRACT FROM AUTHOR]

Los plátanos y bananos son cultivos sensibles al déficit hídrico. Las sequías cada vez más prolongadas sugieren la necesidad de obtener plantas tolerantes a este factor; la selección temprana de estas plantas, comparada con la selección en campo, permite ahorrar tiempo y trabajar con mayores volúmenes de individuos. Para ello es conveniente contar con cultivares patrones cuya respuesta al déficit hídrico in vitro sea favorable. El objetivo del presente trabajo fue determinar la respuesta de cultivares de Musa spp. con diferente composición genómica al estrés hídrico inducido in vitro con polietilenglicol 6000 (PEG-6000). Se estudiaron los cultivares ‘Pelipita’ (ABB), ‘Manzano’ (AAB) y ‘Grande naine’ (AAA). El estrés se indujo con 30 g/L de PEG-6000 en medio de cultivo semisólido de multiplicación. A los 30 días se evaluaron variables indicadoras de estrés morfológicas (altura y número de brotes por explante), fisiológicas (masa fresca y masa seca) y bioquímicas (contenido prolina, peróxido de hidrógeno y malondialdehido). En el cultivar ‘Pelipita’ se afectó solamente la altura de las plantas, mientras que en los demás se afectaron todas las variables excepto la masa seca en el ‘Manzano’. En este último y en el ‘Grande naine’ se incrementó la prolina, el peróxido de hidrógeno y el malondialdehido, lo que evidenció un mayor estrés oxidativo y daño en las membranas celulares. Los cultivares estudiados, pudieran emplearse como controles de tolerancia (‘Pelipita’) y sensibilidad (‘Grande naine’ y ‘Manzano’) en la selección in vitro de plantas tolerantes a la sequía, en futuros programas de mejoramiento genético.

Cassava (Manihot esculenta Crantz) is an important crop in Africa, Asia, Latin America, and the Caribbean. This species grows adequately in drought conditions and is ideal to ensure food safety in marginal environments, such as soils with low fertility and low rainfall conditions. Complementary irrigation practices can be used, or genotypes with good yield potential can be identified against these conditions to enhance productivity in those environments. For this reason, this research aimed to study several physiological mechanisms and agronomical characteristics in eight cassava clones under prolonged water deficit. The experimental design was a split-plot where the principal plot was composed of three irrigation treatments (7, 15, and 21 days without irrigation, DWI) and the secondary plot by the eight clones. The results showed that cassava plants against drought conditions (21 DWI) decreased their growth, foliar expansion, and partially closed the stomata, avoiding water losses through transpiration. The variables of the net assimilation rate of CO2, yield, and biomass accumulation were not affected by the maximum drought period. The best clones under drought were Guajira, Guajira 3, Guajira 4, Concha Rosada, and MeVen 77-1. The frequency of irrigation 15 DWI increased the variables of gas exchange and vegetative growth. This behavior is due to the ability to tolerate complex conditions through morphological and physiological mechanisms, among them, long life leaf, stomatal control, and high photosynthetic potential. [ABSTRACT FROM AUTHOR]

Copyright of Ciencia Política is the property of Universidad Nacional de Colombia 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.)

The climatic variations make difficult to plan activities in agricultural systems, it is necessary to update the knowledge of local climate conditions. This study analyzes the climatic variability of relevant agricultural regions in Boyacá and Cundinamarca. Modeling behaviors of climatic variables of agricultural interest are identified, likewise, the intra-annual analysis of extreme events is carried out and areas with water deficiencies and excesses are identified through a hydroclimatic balance. Finally, areas with greater frequency of deficiencies and water excess conditions in soil were identified on a monthly basis by index of the Palmer Drought Severity Index (PSDI). The results indicate that the two zones of study do not show great climatic differences between them, however, it is important to carry out separately study of them looking for provide local useful information for producers. Saboyá in the Ubate Valley and Chiquinquirá and Sotaquirá in the Alto Chicamocha were affected by both, deficiency and excess, water events. The 1997 El Niño event had a stronger impact in the Ubaté Valley and Chiquinquirá area. Moreover, Alto Chicamocha region showed the biggest rainfall reduction registered in 1992, which matchs with an El Niño event. In terms of excess water, 2011 perceived rainfall increases of more than 50% in those two regions, this behavior responded to La Niña event that year. [ABSTRACT FROM AUTHOR]

In the locality of El Espinal, Tolima, the effect of water stress on leaf water potential and gas exchange of plants three clones of cacao (Theobroma cacao L) was evaluated. The experiment was established in a split plot design in randomized block arrangement. The main plot was four levels of available soil water, subplot grafted seedlings to three months of three clones with five repetitions. The results showed highly significant differences (P

Protocols were established for screening rice genotypes for tolerance to water-limited conditions under field conditions. These protocols were successfully used to select the best genotypes for further experiments. Rice genotypes responded differently when subjected to water-limited conditions. Experiments conducted under field conditions indicated that rice genotypes Curinga and CT6241 performed much better in terms of grain yield under water-limited conditions than varieties Azucena, Nerica, CICA8 and Palmar. Curinga, CT6241, CICA8 and Palmar were selected for further studies. The first two genotypes are tolerant and whereas the last two are susceptible to water stress.Se estableció un protocolo para la selección de genotipos de arroz tolerantes a déficit hídrico bajo condiciones de campo. El protocolo desarrollado permitió la separación de los genotipos evaluados por su tolerancia a estrés hídrico, los cuales respondieron en forma diferente. En condiciones limitantes de agua, los genotipos Curinga y CT6241 presentaron mejor comportamiento en términos de rendimiento que las variedades Azucena, CICA8, Nerica y Palmar. Curinga, CT6241, CICA8 y Palmar fueron seleccionados para estudios futuros. Los dos primeros como genotipos tolerantes y los dos últimos como susceptibles al estrés hídrico.

In the locality of El Espinal, Tolima, the effect of water stress on leaf water potential and gas exchange of plants three clones of cacao (Theobroma cacao L) was evaluated. The experiment was established in a split plot design in randomized block arrangement. The main plot was four levels of available soil water, subplot grafted seedlings to three months of three clones with five repetitions. The results showed highly significant differences (P <0.01) in content of soil water, but no differences between the materials evaluated. The loss of water in the soil decreases leaf water potential (Ψf) and causes stomatal closure altering gas exchange and vapor pressure deficit (DPV) accentuates mainly at noon with increasing evapotranspiration. The magnitude of impact of water deficit depends on climatic variations throughout the day. The climatic variables that affect plant development, are temperature and relative humidity in the form of DPV. Net photosynthesis and growth of cocoa seedlings are physiological variables very sensitive to excess and especially to water deficit. [ABSTRACT FROM AUTHOR]