scholarly journals Drivers and Environmental Impacts of Vegetation Greening in a Semi-Arid Region of Northwest China since 2000

2021 ◽  
Vol 13 (21) ◽  
pp. 4246
Author(s):  
Zhenzong Wu ◽  
Jian Bi ◽  
Yifei Gao
Keyword(s):  
Arid Region ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Agricultural Practices ◽  
Northwest China ◽  
Terrestrial Vegetation ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Semi Arid Region ◽  
Semi Arid ◽  
Dynamics Of Vegetation

The dynamics of terrestrial vegetation have changed a lot due to climate change and direct human interference. Monitoring these changes and understanding the mechanisms driving them are important for better understanding and projecting the Earth system. Here, we assessed the dynamics of vegetation in a semi-arid region of Northwest China for the years from 2000 to 2019 through satellite remote sensing using Vegetation Index (VI) data from the Moderate Resolution Imaging Spectroradiometer (MODIS), and analyzed the interannual covariation between vegetation and three climatic factors—air temperature, precipitation, and vapor pressure deficit (VPD)—at nine meteorological stations. The main findings of this research are: (1) herbaceous land greened up much more than forests (2.85%/year vs. 1.26%/year) in this semi-arid region; (2) the magnitudes of green-up for croplands and grasslands were very similar, suggesting that agricultural practices, such as fertilization and irrigation, might have contributed little to vegetation green-up in this semi-arid region; and (3) the interannual dynamics of vegetation at high altitudes in this region correlate little with temperature, precipitation, or VPD, suggesting that factors other than temperature and moisture control the interannual vegetation dynamics there.

scholarly journals THERMAL CHARACTERIZATION OF THE FAVELONE DERIVATIVES (CNIDOSCOLUS QUERCIFOLIUS) BY THERMOGRAVIMETRY AND DIFFERENTIAL SCANNING CALORIMETRY

2006 ◽  
Vol 05 (3) ◽  
pp. 8-20
Author(s):  
José Carlos Oliveira SANTOS ◽  
Lionete Dantas NUNES ◽  
Sylvia Berenice NÓBREGA ◽  
Dantas José Pires PUZINSKI ◽  
Antonio Gouveia SOUZA
Keyword(s):  
Differential Scanning Calorimetry ◽  
Arid Region ◽  
Agricultural Practices ◽  
Thermal Characterization ◽  
Northeastern Brazil ◽  
Scanning Calorimetry ◽  
Semi Arid Region ◽  
Derivatives Of ◽  
Semi Arid

A thermal analysis has been applied to characterization of food and food products. Taking into account the problems of desertification and agricultural practices able to provide income to the population at the semi-arid region of Northeastern Brazil, this work presents the results of the chemical, thermal and kinetic characterization by thermogravimetry and differential scanning calorimetry of the seed derivatives of favelone (cnidoscolus quercifolius), aiming at the application of these materials as an alternative of food source for animals and for the human population at this brazilian region.

scholarly journals Spatio-Temporal Response of Vegetation Indices to Rainfall and Temperature in A Semiarid Region

2020 ◽  
Vol 12 (5) ◽  
pp. 1939 ◽  
Author(s):  
Edith Olmos-Trujillo ◽  
Julián González-Trinidad ◽  
Hugo Júnez-Ferreira ◽  
Anuard Pacheco-Guerrero ◽  
Carlos Bautista-Capetillo ◽  
...  
Keyword(s):  
Arid Region ◽  
Climatic Factors ◽  
Time Lag ◽  
Vegetation Indices ◽  
Climatic Variables ◽  
Semiarid Region ◽  
Linear Regression Models ◽  
Spatio Temporal ◽  
Semi Arid Region ◽  
Semi Arid

In this research, vegetation indices (VIs) were analyzed as indicators of the spatio-temporal variation of vegetation in a semi-arid region. For a better understanding of this dynamic, interactions between vegetation and climate should be studied more widely. To this end, the following methodology was proposed: (1) acquire the NDVI, EVI, SAVI, MSAVI, and NDMI by classification of vegetation and land cover categories in a monthly period from 2014 to 2018; (2) perform a geostatistical analysis of rainfall and temperature; and (3) assess the application of ordinary and uncertainty least squares linear regression models to experimental data from the response of vegetation indices to climatic variables through the BiDASys (bivariate data analysis system) program. The proposed methodology was tested in a semi-arid region of Zacatecas, Mexico. It was found that besides the high values in the indices that indicate good health, the climatic variables that have an impact on the study area should be considered given the close relationship with the vegetation. A better correlation of the NDMI and EVI with rainfall and temperature was found, and similarly, the relationship between VIs and climatic factors showed a general time lag effect. This methodology can be considered in management and conservation plans of natural ecosystems, in the context of climate change and sustainable development policies.

scholarly journals Soil Moisture and Irrigation Mapping in A Semi-Arid Region, Based on the Synergetic Use of Sentinel-1 and Sentinel-2 Data

2018 ◽  
Vol 10 (12) ◽  
pp. 1953 ◽  
Author(s):  
Safa Bousbih ◽  
Mehrez Zribi ◽  
Mohammad El Hajj ◽  
Nicolas Baghdadi ◽  
Zohra Lili-Chabaane ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Arid Region ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Cloud Model ◽  
Remotely Sensed Data ◽  
Semi Arid Region ◽  
Semi Arid ◽  
Sentinel 2 ◽  
Reference Fields

This paper presents a technique for the mapping of soil moisture and irrigation, at the scale of agricultural fields, based on the synergistic interpretation of multi-temporal optical and Synthetic Aperture Radar (SAR) data (Sentinel-2 and Sentinel-1). The Kairouan plain, a semi-arid region in central Tunisia (North Africa), was selected as a test area for this study. Firstly, an algorithm for the direct inversion of the Water Cloud Model (WCM) was developed for the spatialization of the soil water content between 2015 and 2017. The soil moisture retrieved from these observations was first validated using ground measurements, recorded over 20 reference fields of cereal crops. A second method, based on the use of neural networks, was also used to confirm the initial validation. The results reported here show that the soil moisture products retrieved from remotely sensed data are accurate, with a Root Mean Square Error (RMSE) of less than 5% between the two moisture products. In addition, the analysis of soil moisture and Normalized Difference Vegetation Index (NDVI) products over cultivated fields, as a function of time, led to the classification of irrigated and rainfed areas on the Kairouan plain, and to the production of irrigation maps at the scale of individual fields. This classification is based on a decision tree approach, using a combination of various statistical indices of soil moisture and NDVI time series. The resulting irrigation maps were validated using reference fields within the study site. The best results were obtained with classifications based on soil moisture indices only, with an accuracy of 77%.

scholarly journals Changes in soil physicochemical properties and soil bacterial community in alfalfa (Medicago sativa L.) / oat (Avena nuda L.) intercropping system

2021 ◽  
Author(s):  
Xiaojing Liu ◽  
Yajiao Zhao ◽  
Changchun Tong ◽  
Yong Wu
Keyword(s):  
Bacterial Community ◽  
Arid Region ◽  
Rhizosphere Soil ◽  
Soil Health ◽  
Illumina Miseq ◽  
Northwest China ◽  
Carbonate Content ◽  
Effective Measure ◽  
Semi Arid Region ◽  
Semi Arid

Abstract Aims Semi-arid region in northwest China is characterized by barren soil, high soil pH and high carbonate content.Methods In order to improve the soil health status in this area, we studied the effects of alfalfa/oat intercropping on rhizosphere soil nutrients and bacterial community by Illumina MiSeq technology in the 3rd year.Results The results showed that SOM significantly increased in the rhizosphere soil of intercropped compared with monoculture. AN, AP and AK of intercropping were significantly higher than those of monoculture of oat. Bacterial reads number, population taxonomic unit, richness and diversity all showed that intercropping were greater than monoculture. In terms of bacterial phylum, Proteobacteria, Bacteroidetes, Chloroflexi, Actinobacteria, Planctomycetes and Acidobacteria were dominant populations. The abundances of Proteobacteria, Acidobacteria, Cyanobacteria and Gemmatimonadetes were greater in intercropping systems than that in monoculture systems. At genus level, Opitutus, Pseudomonas, Gemmatimonas and Flavobacterium in intercropping were all higher than those in monoculture. At the same time, proteobacteria, bacteroidetes and actinobacteria were significantly positively correlated with SOM, TN and AN.Conclusions This result indicated that alfalfa/oat intercropping can reduce the pH and significantly improve the microbial environment and nutrients of rhizosphere soil in northwest semi-arid region. Meanwhile, the rhizosphere soil microbial community and nutrients interact and regulate each other. Therefore, alfalfa/oat intercropping is an effective measure that improve soil environment in northwest semi-arid region.

scholarly journals Attribution of satellite observed vegetation trends in a hyper-arid region of the Heihe River Basin, Central Asia

2014 ◽  
Vol 11 (2) ◽  
pp. 1529-1554 ◽  
Author(s):  
Y. Wang ◽  
M. L. Roderick ◽  
Y. Shen ◽  
F. Sun
Keyword(s):  
Climate Change ◽  
Central Asia ◽  
Vegetation Cover ◽  
Arid Region ◽  
Vegetation Index ◽  
Northwest China ◽  
Heihe River ◽  
Terrestrial Vegetation ◽  
Fractional Vegetation Cover ◽  
Green Vegetation

Abstract. Terrestrial vegetation dynamics are closely influenced by both climate change and by direct human activities that modify land use and/or land cover (LULCC). Both can change over time in a monotonic way and it can be difficult to separate the effects of climate change from LULCC on vegetation. Here we attempt to attribute the trend of fractional green vegetation cover to climate change and to human activity in Ejina region, a hyper-arid landlocked region in northwest China. This region is dominated by extensive deserts with relatively small areas of irrigation located along the major water courses as is typical throughout much of Central Asia. Variations of fractional vegetation cover from 2000 to 2012 were determined using Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation index data with 250 m spatial resolution over 16 day intervals. We found that the fractional vegetation cover in this hyper-arid region is very low, but that the mean growing season vegetation cover has increased from 3.4% in 2000 to 4.5% in 2012. The largest contribution to the overall greening was due to changes in green vegetation cover of the extensive desert areas with a smaller contribution due to changes in the area of irrigated land. Comprehensive analysis with different precipitation data sources found that the greening of the desert was associated with increases in regional precipitation. We found that the area of land irrigated each year was mostly dependent on the runoff gauged one year earlier. Taken together, water availability both from precipitation in the desert and runoff inflow for the irrigation agricultural lands can explain at least 52% of the total variance in regional vegetation cover from 2000 to 2010.

scholarly journals DYNAMICS OF BORDER VEGETATION AND EDAPHIC-CLIMATOLOGY OF CLEARINGS IN AN AREA OF CAATINGA IN THE SEMI-ARID REGION OF BRAZIL.

FLORESTA ◽  
2019 ◽  
Vol 49 (3) ◽  
pp. 523
Author(s):  
Azenate Campos Gomes ◽  
Jacob Silva Souto ◽  
Alecksandra Vieira de Lacerda
Keyword(s):  
Natural Regeneration ◽  
Arid Region ◽  
Climatic Factors ◽  
Floristic Composition ◽  
Ground Level ◽  
Climatic Parameters ◽  
Historical Process ◽  
Negative Impacts ◽  
Semi Arid Region ◽  
Semi Arid

The use and unsustainable occupation in the semi-arid areas have resulted throughout its historical process in strong negative impacts by opening clearings in the areas of Caatinga, which need to be identified and studied to reverse this situation. The objective of this work was to analyze the dynamics of border of vegetation and edaphic-climatological clearings in a Caatinga area in the municipality of Sumé, state of Paraíba, Brazil. The study was conducted in the Experimental Area Reserved for Ecology and Dynamic Studies of the Caatinga of LAEB/CDSA/UFCG (7°39'38.8'' S and 36°53'42.4'' W, with 538 m of altitude). The clearings were isolated, and monitored between 2013 and 2015, soil and agrometeorological data were collected. Shrubs and live trees with diameter at ground level and height >0.03 and >1.0 m respectively were considered as border individuals. The highest values of soil density were observed for the clearings that presented the lowest levels of organic matter. 62% of the clearings had an increase in their area due to the high mortality of Croton blanchetianus Baill. and 38% had their area reduced due to the colonization of young, mainly Jatropha mollissima (Pohl) Baill. The floristic composition of the border comprised six species distributed in six genera and four families, being Fabaceae and Euphorbiaceae the most representative. The number of border individuals and recorded mortality were fully correlated with climatic parameters. Therefore, although the clearings are in the process of natural regeneration, climatic factors have strongly influenced the delay of this process. 

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