Effects of Soil Moisture on Shrub Seedling Survival in Semi-Arid Grassland

Ecology ◽  
1991 ◽  
Vol 72 (3) ◽  
pp. 1138-1149 ◽  
Author(s):  
Graham N. Harrington
Keyword(s):  
Soil Moisture ◽  
Seedling Survival ◽  
Semi Arid

scholarly journals Climate Differently Impacts the Growth of Coexisting Trees and Shrubs under Semi-Arid Mediterranean Conditions

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 381
Author(s):  
J. Julio Camarero ◽  
Cristina Valeriano ◽  
Antonio Gazol ◽  
Michele Colangelo ◽  
Raúl Sánchez-Salguero
Keyword(s):  
Soil Moisture ◽  
Radial Growth ◽  
Pinus Halepensis ◽  
Growth Dynamics ◽  
Early Summer ◽  
Growth Responses ◽  
Shrub Species ◽  
High Soil Moisture ◽  
Semi Arid ◽  
Mediterranean Conditions

Background and Objectives—Coexisting tree and shrub species will have to withstand more arid conditions as temperatures keep rising in the Mediterranean Basin. However, we still lack reliable assessments on how climate and drought affect the radial growth of tree and shrub species at intra- and interannual time scales under semi-arid Mediterranean conditions. Materials and Methods—We investigated the growth responses to climate of four co-occurring gymnosperms inhabiting semi-arid Mediterranean sites in northeastern Spain: two tree species (Aleppo pine, Pinus halepensis Mill.; Spanish juniper, Juniperus thurifera L.) and two shrubs (Phoenicean juniper, Juniperus phoenicea L.; Ephedra nebrodensis Tineo ex Guss.). First, we quantified the intra-annual radial-growth rates of the four species by periodically sampling wood samples during one growing season. Second, we quantified the climate–growth relationships at an interannual scale at two sites with different soil water availability by using dendrochronology. Third, we simulated growth responses to temperature and soil moisture using the forward, process-based Vaganov‒Shashkin (VS-Lite) growth model to disentangle the main climatic drivers of growth. Results—The growth of all species peaked in spring to early summer (May–June). The pine and junipers grew after the dry summer, i.e., they showed a bimodal growth pattern. Prior wet winter conditions leading to high soil moisture before cambium reactivation in spring enhanced the growth of P. halepensis at dry sites, whereas the growth of both junipers and Ephedra depended more on high spring–summer soil moisture. The VS-Lite model identified these different influences of soil moisture on growth in tree and shrub species. Conclusions—Our approach (i) revealed contrasting growth dynamics of co-existing tree and shrub species under semi-arid Mediterranean conditions and (ii) provided novel insights on different responses as a function of growth habits in similar drought-prone regions.

scholarly journals Suitability Evaluation of Typical Drought Index in Soil Moisture Retrieval and Monitoring Based on Optical Images

2020 ◽  
Vol 12 (16) ◽  
pp. 2587
Author(s):  
Yan Nie ◽  
Ying Tan ◽  
Yuqin Deng ◽  
Jing Yu
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Arid Regions ◽  
Drought Index ◽  
Dynamic Monitoring ◽  
Landsat 8 ◽  
Landsat 8 Oli ◽  
Rapid Acquisition ◽  
Semi Arid ◽  
Soil Moisture Inversion

As a basic agricultural parameter in the formation, transformation, and consumption of surface water resources, soil moisture has a very important influence on the vegetation growth, agricultural production, and healthy operation of regional ecosystems. The Aksu river basin is a typical semi-arid agricultural area which seasonally suffers from water shortage. Due to the lack of knowledge on soil moisture change, the water management and decision-making processes have been a difficult issue for local government. Therefore, soil moisture monitoring by remote sensing became a reasonable way to schedule crop irrigation and evaluate the irrigation efficiency. Compared to in situ measurements, the use of remote sensing for the monitoring of soil water content is convenient and can be repetitively applied over a large area. To verify the applicability of the typical drought index to the rapid acquisition of soil moisture in arid and semi-arid regions, this study simulated, compared, and validated the effectiveness of soil moisture inversion. GF-1 WFV images, Landsat 8 OLI images, and the measured soil moisture data were used to determine the Perpendicular Drought Index (PDI), the Modified Perpendicular Drought Index (MPDI), and the Vegetation Adjusted Perpendicular Drought Index (VAPDI). First, the determination coefficients of the correlation analyses on the PDI, MPDI, VAPDI, and measured soil moisture in the 0–10, 10–20, and 20–30 cm depth layers based on the GF-1 WFV and Landsat 8 OLI images were good. Notably, in the 0–10 cm depth layers, the average determination coefficient was 0.68; all models met the accuracy requirements of soil moisture inversion. Both indicated that the drought indices based on the Near Infrared (NIR)-Red spectral space derived from the optical remote sensing images are more sensitive to soil moisture near the surface layer; however, the accuracy of retrieving the soil moisture in deep layers was slightly lower in the study area. Second, in areas of vegetation coverage, MPDI and VAPDI had a higher inversion accuracy than PDI. To a certain extent, they overcame the influence of mixed pixels on the soil moisture spectral information. VAPDI modified by Perpendicular Vegetation Index (PVI) was not susceptible to vegetation saturation and, thus, had a higher inversion accuracy, which makes it performs better than MPDI’s in vegetated areas. Third, the spatial heterogeneity of the soil moisture retrieved by the GF-1 WFV and Landsat 8 OLI image were similar. However, the GF-1 WFV images were more sensitive to changes in the soil moisture, which reflected the actual soil moisture level covered by different vegetation. These results provide a practical reference for the dynamic monitoring of surface soil moisture, obtaining agricultural information and agricultural condition parameters in arid and semi-arid regions.

Controls of surface soil moisture spatial patterns and their temporal stability in a semi-arid steppe

2010 ◽  
Vol 24 (18) ◽  
pp. 2507-2519 ◽  
Author(s):  
Y. Zhao ◽  
S. Peth ◽  
X. Y. Wang ◽  
H. Lin ◽  
R. Horn
Keyword(s):  
Soil Moisture ◽  
Spatial Patterns ◽  
Surface Soil ◽  
Temporal Stability ◽  
Surface Soil Moisture ◽  
Arid Steppe ◽  
Semi Arid

Seasonal variation of deep soil moisture under different land uses on the semi-arid Loess Plateau of China

2018 ◽  
Vol 19 (3) ◽  
pp. 1179-1189 ◽  
Author(s):  
Bowei Yu ◽  
Gaohuan Liu ◽  
Qingsheng Liu ◽  
Chong Huang ◽  
He Li ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Seasonal Variation ◽  
Loess Plateau ◽  
Land Uses ◽  
Deep Soil ◽  
Semi Arid

scholarly journals Relating surface backscatter response from TRMM Precipitation Radar to soil moisture: results over a semi-arid region

2009 ◽  
Vol 6 (5) ◽  
pp. 6425-6454
Author(s):  
H. Stephen ◽  
S. Ahmad ◽  
T. C. Piechota ◽  
C. Tang
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Arid Regions ◽  
Vegetation Index ◽  
Temporal Trends ◽  
Model Parameters ◽  
Precipitation Radar ◽  
Semi Arid

Abstract. The Tropical Rainfall Measuring Mission (TRMM) carries aboard the Precipitation Radar (TRMMPR) that measures the backscatter (σ°) of the surface. σ° is sensitive to surface soil moisture and vegetation conditions. Due to sparse vegetation in arid and semi-arid regions, TRMMPR σ° primarily depends on the soil water content. In this study we relate TRMMPR σ° measurements to soil water content (ms) in Lower Colorado River Basin (LCRB). σ° dependence on ms is studied for different vegetation greenness values determined through Normalized Difference Vegetation Index (NDVI). A new model of σ° that couples incidence angle, ms, and NDVI is used to derive parameters and retrieve soil water content. The calibration and validation of this model are performed using simulated and measured ms data. Simulated ms is estimated using Variable Infiltration Capacity (VIC) model whereas measured ms is acquired from ground measuring stations in Walnut Gulch Experimental Watershed (WGEW). σ° model is calibrated using VIC and WGEW ms data during 1998 and the calibrated model is used to derive ms during later years. The temporal trends of derived ms are consistent with VIC and WGEW ms data with correlation coefficient (R) of 0.89 and 0.74, respectively. Derived ms is also consistent with the measured precipitation data with R=0.76. The gridded VIC data is used to calibrate the model at each grid point in LCRB and spatial maps of the model parameters are prepared. The model parameters are spatially coherent with the general regional topography in LCRB. TRMMPR σ° derived soil moisture maps during May (dry) and August (wet) 1999 are spatially similar to VIC estimates with correlation 0.67 and 0.76, respectively. This research provides new insights into Ku-band σ° dependence on soil water content in the arid regions.

scholarly journals What happens after the catchment caught the storm? Hydrological processes at the small, semi-arid Weatherley catchment, South-Africa

2005 ◽  
Vol 2 ◽  
pp. 237-241 ◽  
Author(s):  
S. Uhlenbrook ◽  
J. Wenninger ◽  
S. Lorentz
Keyword(s):  
South Africa ◽  
Electrical Resistivity ◽  
Soil Moisture ◽  
Experimental Techniques ◽  
Storm Event ◽  
Residence Times ◽  
Hydrological Response ◽  
Flow Paths ◽  
Flow Pathways ◽  
Semi Arid

Abstract. The knowledge of water flow pathways and residence times in a catchment are essential for predicting the hydrological response to a rain storm event. Different experimental techniques are available to study these processes, which are briefly reviewed in this paper. To illustrate this, recent findings from the Weatherley catchment a 1.5 km2 semi-arid headwater in South-Africa, are reported in this paper. Beside classical hydrometric measurements of precipitation and runoff different experimental techniques were applied to explore flow paths (i.e. soil moisture and groundwater measurements, natural tracers, and 2-D electrical resistivity tomographies (ERT)).

Effects of plant density and tillage on growth and grain yield of sorghum (Sorghum bicolor (L.) Moench) under dryland conditions in a semi-arid area in Ethiopia

1987 ◽  
Vol 108 (2) ◽  
pp. 395-401 ◽  
Author(s):  
D. C. Adjei-Twum
Keyword(s):  
Soil Moisture ◽  
Grain Yield ◽  
Plant Density ◽  
Grain Filling ◽  
Arid Area ◽  
Tillage Practices ◽  
Available Soil Moisture ◽  
Cropping Seasons ◽  
Sorghum Bicolor L ◽  
Semi Arid

SummaryEffects of plant density ranging from 44444 to 133333 plants/ha and tillage practices (planting in flat beds (control), in the furrows of open ridges, on the top of open ridges, in the furrows of tie-ridges and on the top of tie-ridges) on growth and grain yield of sorghum were investigated at Kobo, a typical semi-arid area in Ethiopia, during 1980, 1981 and 1982 cropping seasons. Plant growth was limited in the flat beds because they were likely to be deficient in soil moisture and sometimes in the tie-ridging treatments, due to waterlogging. However, planting on the top of tie-ridges produced 1·6, 0·4 and 1·8 t/ha more yield than in the flat beds, the method commonly practised by the Kobo farmers, during 1980, 1981 and 1982 respectively. In all seasons, the effect of plant density did not show marked differences. The plants rather adjusted their reproductive growth and development to the seasonal rainfall and presumably to the available soil moisture at the grain-filling periods. It was concluded that the highest plant density did not reach the optimum for the area. Planting sorghum on the top of tie-ridges is recommended.

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