scholarly journals Response of Four Shrub Species to Different Water Source Components in an Arid Environment

2018 ◽  
Vol 8 (3) ◽  
pp. 166 ◽  
Author(s):  
A. Wagner ◽  
D. A. Devitt ◽  
B. Bird ◽  
R. Jasoni ◽  
J. A. Arnone III
Keyword(s):  
Soil Water ◽  
Great Basin ◽  
Vadose Zone ◽  
Soil Salinity ◽  
Water Source ◽  
Arid Environment ◽  
Water Diversion ◽  
Sarcobatus Vermiculatus ◽  
Shrub Species ◽  
Growing Period

Shrubland species in the Great Basin (USA) depend on soil water recharged from precipitation and/or groundwater for survival and growth. Climate warming and possible basin water diversion could alter the amount and timing of water availability to these plants. The objective of this study was to quantify the extent to which each of four co-occurring shrub species, big sage [Artemisia tridentata], rabbitbrush [Ericameria nauseosus], greasewood [Sarcobatus vermiculatus] and shadscale [Atriplex confertifolia)) acquired water from different sources (precipitation, soil vadose zone and/or groundwater) during a growing season. Soil salinity increased linearly with depth over the upper 1.5 m of soil, with salinity ranging from 0.84 to 31.70 dSm-1 in saturation extracts (R2=0.78, p<0.001). Changes in soil water both with depth and time during the growing period indicated that all species accessed soil water from precipitation recharge. Evapotranspiration totals for the growing period exceeded total precipitation by 137 mm, indicating that plants also used water stored deeper within the vadose zone and/or from groundwater (particularly) by the phreatophyte greasewood. Delta18O in the soil solution declined linearly with depth over the upper 100 cm (R2=0.80, p<0.001). Delta18O values in greasewood corresponded closely to Delta18O values measured deeper in the vadose zone and groundwater. Output from a mixing model indicated a decrease in groundwater reliance for greasewood from 30% in July to 2% in September, with a major shift to deeper soil water in the vadose zone (180 cm depth) (38% in July to 97% in September). Our data suggested that the four shrub species at our site were able to coexist because of their different spatial, temporal, and physiological uses of available soil water, reflecting possible water resource partitioning based on differences in response to precipitation, ability to extract water at deeper depths and variable tolerance to elevated levels of soil salinity to access groundwater.

scholarly journals The Ecological Relationship of Groundwater–Soil–Vegetation in the Oasis–Desert Transition Zone of the Shiyang River Basin

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1642
Author(s):  
Le Cao ◽  
Zhenlong Nie ◽  
Min Liu ◽  
Lifang Wang ◽  
Jinzhe Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Soil Salinity ◽  
Shallow Groundwater ◽  
Water Source ◽  
Northwest China ◽  
Soil Salinization ◽  
Arid Areas ◽  
Important Indicator ◽  
Vegetation Growth

Groundwater is an important ecological water source in arid areas. Groundwater depth (GWD) is an important indicator that affects vegetation growth and soil salinization. Clarifying the coupling relationship between vegetation, groundwater, and soil in arid areas is beneficial to the prevention of environmental problems such as desertification and salinization. Existing studies lack research on the water–soil–vegetation relationship in typical areas, especially in shallow groundwater areas. In this study, the shallow groundwater area in Minqin, northwest China, was taken as study area, and vegetation surveys and soil samples collection were conducted. The relationships between vegetation fractional coverage (VFC) and GWD, soil salinity, soil moisture, and precipitation were comprehensively analyzed. The results showed low soil salinity in the riparian zone and high soil salinity in other shallow-buried areas with salinization problems. Soil salinity was negatively correlated with VFC (R = −0.4). When soil salinity >3 g/kg, VFC was less than 20%. Meanwhile, when GWD >10 m, VFC was usually less than 15%. In the areas with soil salinity <3 g/kg, when GWD was in the range of 4–10 m, VFC was positively correlated with soil moisture content (R = 0.99), and vegetation growth mainly depended on surface soil water, which was significantly affected by precipitation. When GWD was less than 4 m, VFC was negatively correlated with GWD (R = −0.78), and vegetation growth mainly relied on groundwater and soil water. There are obvious ecological differences in the shallow-buried areas in Minqin. Hence, it is reasonable to consider zoning and grading policies for ecological protection.

scholarly journals The Effect of Irrigation Rate on the Water Relations of Young Citrus Trees in High-Density Planting

2021 ◽  
Vol 13 (4) ◽  
pp. 1759
Author(s):  
Said A. Hamido ◽  
Kelly T. Morgan
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Salinity ◽  
Planting Density ◽  
Stem Water Potential ◽  
Irrigation Rate ◽  
Biological Stress ◽  
Stem Water ◽  
Water Contents ◽  
Soil Water Contents

The availability and proper irrigation scheduling of water are some of the most significant limitations on citrus production in Florida. The proper volume of citrus water demand is vital in evaluating sustainable irrigation approaches. The current study aims to determine the amount of irrigation required to grow citrus trees at higher planting densities without detrimental impacts on trees’ water relation parameters. The study was conducted between November 2017 and September 2020 on young sweet orange (Citrus sinensis) trees budded on the ‘US-897’ (Cleopatra mandarin x Flying Dragon trifoliate orange) citrus rootstock transplanted in sandy soil at the Southwest Florida Research and Education Center (SWFREC) demonstration grove, near Immokalee, Florida. The experiment contained six planting densities, including 447, 598, and 745 trees per ha replicated four times, and 512, 717, and 897 trees per ha replicated six times. Each density treatment was irrigated at 62% or 100% during the first 15 months between 2017 and 2019 or one of the four irrigation rates (26.5, 40.5, 53, or 81%) based on the calculated crop water supplied (ETc) during the last 17 months of 2019–2020. Tree water relations, including soil moisture, stem water potential, and water supplied, were collected periodically. In addition, soil salinity was determined. During the first year (2018), a higher irrigation rate (100% ETc) represented higher soil water contents; however, the soil water content for the lower irrigation rate (62% ETc) did not represent biological stress. One emitter per tree regardless of planting density supported stem water potential (Ψstem) values between −0.80 and −0.79 MPa for lower and full irrigation rates, respectively. However, when treatments were adjusted from April 2019 through September 2020, the results substantially changed. The higher irrigation rate (81% ETc) represented higher soil water contents during the remainder of the study, the lower irrigation rate (26.5% ETc) represents biological stress as a result of stem water potential (Ψstem) values between −1.05 and −0.91 MPa for lower and higher irrigation rates, respectively. Besides this, increasing the irrigation rate from 26.5% to 81%ETc decreased the soil salinity by 33%. Although increasing the planting density from 717 to 897 trees per hectare reduced the water supplied on average by 37% when one irrigation emitter was used to irrigate two trees instead of one, applying an 81% ETc irrigation rate in citrus is more efficient and could be managed in commercial groves.

scholarly journals Contrasting Water Use Strategies of Tamarix ramosissima in Different Habitats in the Northwest of Loess Plateau, China

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2791
Author(s):  
Pengyan Su ◽  
Mingjun Zhang ◽  
Deye Qu ◽  
Jiaxin Wang ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Loess Plateau ◽  
Meteoric Water ◽  
Water Source ◽  
Water Sources ◽  
Tamarix Ramosissima ◽  
Water Line ◽  
Meteoric Water Line ◽  
Utilization Ratio

As a species for ecological restoration in northern China, Tamarix ramosissima plays an important role in river protection, flood control, regional climate regulation, and landscape construction with vegetation. Two sampling sites were selected in the hillside and floodplain habitats along the Lanzhou City, and the xylems of T. ramosissima and potential water sources were collected, respectively. The Bayesian mixture model (MixSIAR) and soil water excess (SW-excess) were applied to analyze the relationship on different water pools and the utilization ratios of T. ramosissima to potential water sources in two habitats. The results showed that the slope and intercept of local meteoric water line (LMWL) in two habitats were smaller compared with the global meteoric water line (GMWL), which indicated the existence of drier climate and strong evaporation in the study area, especially in the hillside habitat. Except for the three months in hillside, the SW-excess of T. ramosissima were negative, which indicated that xylems of T. ramosissima are more depleted in δ2H than the soil water line. In growing seasons, the main water source in hillside habitat was deep soil water (80~150 cm) and the utilization ratio was 63 ± 17% for T. ramosissima, while the main water source in floodplain habitat was shallow soil water (0~30 cm), with a utilization ratio of 42.6 ± 19.2%, and the water sources were different in diverse months. T. ramosissima has a certain adaptation mechanism and water-use strategies in two habitats, and also an altered water uptake pattern in acquiring the more stable water. This study will provide a theoretical basis for plant water management in ecological environment protection in the Loess Plateau.

A simple numerical model to estimate water availability in saline soils

Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 264 ◽  
Author(s):  
Mohammad Hossein Mohammadi ◽  
Mahnaz Khataar
Keyword(s):  
Numerical Model ◽  
Water Content ◽  
Soil Water ◽  
Water Uptake ◽  
Soil Salinity ◽  
Irrigation Water ◽  
Weighting Function ◽  
Water Salinity ◽  
Irrigation Water Salinity ◽  
Evapotranspiration Rate

We developed a numerical model to predict soil salinity from knowledge of evapotranspiration rate, crop salt tolerance, irrigation water salinity, and soil hydraulic properties. Using the model, we introduced a new weighting function to express the limitation imposed by salinity on plant available water estimated by the integral water capacity concept. Lower and critical limits of soil water uptake by plants were also defined. We further analysed the sensitivity of model results to underlying parameters using characteristics given for corn, cowpea, and barley in the literature and two clay and sandy loam soils obtained from databases. Results showed that, between two irrigation events, soil salinity increased nonlinearly with decreasing soil water content especially when evapotranspiration and soil drainage rate were high. The salinity weighting function depended greatly on the plant sensitivity to salinity and irrigation water salinity. This research confirmed that both critical and lower limits (in terms of water content) of soil water uptake by plants increased with evapotranspiration rate and irrigation water salinity. Since the presented approach is based on a physical concept and well-known plant parameters, soil hydraulic characteristics, irrigation water salinity, and meteorological conditions, it may be useful in spatio-temporal modelling of soil water quality and quantity and prediction of crop yield.

scholarly journals Intensified Interspecific Competition for Water after Afforestation with Robinia pseudoacacia into a Native Shrubland in the Taihang Mountains, Northern China

2021 ◽  
Vol 13 (2) ◽  
pp. 807
Author(s):  
Wanrui Zhu ◽  
Wenhua Li ◽  
Peili Shi ◽  
Jiansheng Cao ◽  
Ning Zong ◽  
...  
Keyword(s):  
Soil Water ◽  
Introduced Species ◽  
Water Use ◽  
Rainy Season ◽  
Robinia Pseudoacacia ◽  
Water Source ◽  
Total Water ◽  
Mountainous Areas ◽  
Water Competition ◽  
Seasonal Water Use

Understanding how soil water source is used spatiotemporally by tree species and if native species can successfully coexist with introduced species is crucial for selecting species for afforestation. In the rocky mountainous areas of the Taihang Mountains, alien Robinia pseudoacacia L. has been widely afforested into the native shrublands dominated by Ziziphus jujuba Mill var. spinosa and Vitex negundo L. var. heterophylla to improve forest coverage and soil nutrients. However, little is known about the water relation among species, especially seasonal water use sources in different microsites. We selected the soil and plant xylem samples of two opposite microtopographic sites (ridge and valley) monthly in the growth season to analyze isotope composition. The proportions of water sources were quantified by the MixSIAR model and compared pairwise between species, microsites and seasons. We found that deep subsoil water at a depth of 40–50 cm contributed up to 50% of the total water uptake for R. pseudoacacia and Z. jujuba in the growing season, indicating that they stably used deeper soil water and had intense water competition. However, V. negundo had a more flexible water use strategy, which derived more than 50% of the total water uptake from the soil layer of 0–10 cm in the rainy season, but majorly captured soil water at a depth of 30–50 cm in the dry season. Therefore, high niche overlaps were shown in V. negundo with the other two species in the dry season, but niche segregation was seen in the rainy season. The microtopographic sites did not shift the seasonal dynamic of the water source use patterns of the three studied species, but the water use niche overlap was higher in the valley than in the ridge. Taken together, the introduced species R. pseudoacacia intensified water competition with the native semi-arbor species Z. jujuba, but it could commonly coexist with the native shrub species V. negundo. Therefore, our study on seasonal water use sources in different microsites provides insight into species interaction and site selection for R. pseudoacacia afforestation in the native shrub community in rocky mountainous areas. It is better to plant R. pseudoacacia in the shrubland in the valley so as to avoid intense water competition and control soil erosion.

scholarly journals Imaging Spectroscopic Analysis of Biochemical Traits for Shrub Species in Great Basin, USA

2018 ◽  
Vol 10 (10) ◽  
pp. 1621 ◽  
Author(s):  
Yi Qi ◽  
Susan Ustin ◽  
Nancy Glenn
Keyword(s):  
Great Basin ◽  
Land Surface ◽  
Imaging Spectroscopy ◽  
Partial Least Square ◽  
Least Square ◽  
Partial Least Square Regression ◽  
Leaf Mass Per Area ◽  
Shrub Species ◽  
Biochemical Traits ◽  
Airborne Imaging

The biochemical traits of plant canopies are important predictors of photosynthetic capacity and nutrient cycling. However, remote sensing of biochemical traits in shrub species in dryland ecosystems has been limited mainly due to the sparse vegetation cover, manifold shrub structures, and complex light interaction between the land surface and canopy. In order to examine the performance of airborne imaging spectroscopy for retrieving biochemical traits in shrub species, we collected Airborne Visible Infrared Imaging Spectrometer—Next Generation (AVIRIS-NG) images and surveyed four foliar biochemical traits (leaf mass per area, water content, nitrogen content and carbon) of sagebrush (Artemesia tridentata) and bitterbrush (Purshia tridentata) in the Great Basin semi-desert ecoregion, USA, in October 2014 and May 2015. We examined the correlations between biochemical traits and developed partial least square regression (PLSR) models to compare spectral correlations with biochemical traits at canopy and plot levels. PLSR models for sagebrush showed comparable performance between calibration (R2: LMA = 0.66, water = 0.7, nitrogen = 0.42, carbon = 0.6) and validation (R2: LMA = 0.52, water = 0.41, nitrogen = 0.23, carbon = 0.57), while prediction for bitterbrush remained a challenge. Our results demonstrate the potential for airborne imaging spectroscopy to measure shrub biochemical traits over large shrubland regions. We also highlight challenges when estimating biochemical traits with airborne imaging spectroscopy data.

Characterization of hydraulic properties in the upper vadose zone for two aquifers in Slovenia

2021 ◽  
Author(s):  
Vesna Zupanc ◽  
Matjaž Glavan ◽  
Miha Curk ◽  
Urša Pečan ◽  
Michael Stockinger ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Soil Water ◽  
Water Flow ◽  
Vadose Zone ◽  
Hydraulic Properties ◽  
Isotope Composition ◽  
Transport Processes ◽  
Precipitation Event ◽  
Water Fluxes ◽  
Flow And Transport

&lt;p&gt;Environmental tracers, present in the environment and provided by nature, provide integrative information about both water flow and transport. For studying water flow and solute transport, the hydrogen and oxygen isotopes are of special interest, as their ratios provide a tracer signal with every precipitation event and are seasonally distributed. In order to follow the seasonal distribution of stable isotopes in the soil water and use this information for identifying hydrological processes and hydraulic properties, soil was sampled three times in three profiles, two on Kr&amp;#353;ko polje aquifer in SE Slovenia and one on Ljubljansko polje in central Slovenia. Isotope composition of soil water was measured with the water-vapor-equilibration method. Based on the isotope composition of soil water integrative information about water flow and transport processes with time and depth below ground were assessed. Porewater isotopes were in similar range as precipitation for all three profiles. &amp;#160;Variable isotope ratios in the upper 60 cm for the different sampling times indicated dynamic water fluxes in this upper part of the vadose zone. Results also showed more evaporation at one sampling location, Brege. The information from stable isotopes will be of importance for further analyzing the water fluxes in the vadose zone of the study sties.&amp;#160;&lt;br&gt;This research was financed by the ARRS BIAT 20-21-32 and IAEA CRP 1.50.18 Multiple isotope fingerprints to identify sources and transport of agro-contaminants. &amp;#160;&lt;/p&gt;

Water source and transmission in Haloxylon ammodendron in the desert margin of the Manas River Basin, China

2021 ◽  
pp. 1-12
Author(s):  
Wanjing Li ◽  
Li Zhao ◽  
Guang Yang ◽  
Ke Yan ◽  
Xinlin He ◽  
...  
Keyword(s):  
Soil Water ◽  
Ecological Restoration ◽  
Moisture Transfer ◽  
Water Source ◽  
Desert Plant ◽  
Contribution Rate ◽  
Haloxylon Ammodendron ◽  
Water Transportation ◽  
Stem Flow ◽  
Average Contribution

Abstract Analysis of water source and moisture transfer characteristics of desert plants is of great significance for ecological restoration in arid areas. In this study, the water source utilized by the desert plant, Haloxylon ammodendron, was analysed using the stable isotope technique, and the water transportation characteristics were obtained based on the proportional heat balance method under different weather conditions. The results showed that (1) before raining, the moisture of H. ammodendron mainly relied on groundwater (the average contribution rate was 34.14%) and on soil water located at a depth of 120–180 cm (the average contribution rate was 29.87%). After the rain, H. ammodendron mainly absorbed soil water from a depth of 60–120 cm (the average contribution rate was 33.19%) and groundwater (the average contribution rate was 30.67%); (2) the stem flow of H. ammodendron showed an obvious diurnal variation, showing a “midday rest” phenomenon. The stem flow showed a peak value, and in sunny days, it was ~2 fold higher than that in cloudy days. (3) The stem flow rate of H. ammodendron varied regularly overtime as follows: August > July > September > June > May, and the meteorological factors affecting its stem flow were solar radiation (0.826) > atmospheric temperature (0.598) > humidity (-0.573). The results provide basic support for the ecological conservation of the desert plant H. ammodendron, while also having important implications for ecological restoration in arid regions.

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