scholarly journals The Depth of Water Taken up by Walnut Trees during Different Phenological Stages in an Irrigated Arid Hilly Area in the Taihang Mountains

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 121 ◽  
Author(s):  
Yang Liu ◽  
Xuemei Zhang ◽  
Shuang Zhao ◽  
Huabing Ma ◽  
Guohui Qi ◽  
...  
Keyword(s):  
Soil Water ◽  
Soil Depth ◽  
Isotope Composition ◽  
Irrigation Management ◽  
Soil Layer ◽  
Root Water Uptake ◽  
Phenological Stages ◽  
Hilly Area ◽  
Fruit Maturity ◽  
Hydrogen And Oxygen Isotope

Understanding how the soil environment impacts root water uptake location and magnitude is important for better management of plant irrigation. In this study, stable hydrogen and oxygen isotope composition were used to determine seasonal variations in the depth of water taken up by walnut trees during different phenological stages in an irrigated arid hilly area in the Taihang Mountains in China. The contributions of soil water at different depths to the water taken up were quantified by the MixSIAR Bayesian isotope mixing model. The results indicated that water taken up by the walnut trees was sourced mainly from soil water in the 0–20 cm soil layer at the sprouting and leaf expansion stages (62.95%), and the 20–40 cm soil layer at blossoming and fruit-bearing (43.45%), fruit expansion (41.8%), and fruit maturity (39.15%) stages. The mean soil depth of the water taken up by the walnut trees gradually decreased as the phenological stages advanced. The proportions of various soil layer water contributions to the walnut trees differed throughout the phenological stages, and the proportion of deeper soil water contributions gradually increased as the phenological stages of walnut trees advanced. The results of the present study indicated that water sources for walnut trees varied by depth during different phenological stages. In addition to soil moisture, soil temperature may also be an important factor affecting the depth of water taken up by walnut trees. The results also provided scientific implications for water-saving irrigation management.

Towards the consideration of soil-root resistances in root water uptake models with macroscopic representations of hydraulic root architecture

2021 ◽  
Author(s):  
Jan Vanderborght ◽  
Valentin Couvreur ◽  
Felicien Meunier ◽  
Andrea Schnepf ◽  
Harry Vereecken ◽  
...  
Keyword(s):  
Root System ◽  
Soil Water ◽  
Water Uptake ◽  
Root Distribution ◽  
Root Architecture ◽  
Soil Layer ◽  
Root Water Uptake ◽  
Hydraulic Architecture ◽  
Root Segments ◽  
Soil Volume

<p>Plant water uptake from soil is an important component of terrestrial water cycle with strong links to the carbon cycle and the land surface energy budget. To simulate the relation between soil water content, root distribution, and root water uptake, models should represent the hydraulics of the soil-root system and describe the flow from the soil towards root segments and within the 3D root system architecture according to hydraulic principles. We have recently demonstrated how macroscopic relations that describe the lumped water uptake by all root segments in a certain soil volume, e.g. in a thin horizontal soil layer in which soil water potentials are uniform, can be derived from the hydraulic properties of the 3D root architecture. The flow equations within the root system can be scaled up exactly and the total root water uptake from a soil volume depends on only two macroscopic characteristics of the root system: the root system conductance, K<sub>rs</sub>, and the uptake distribution from the soil when soil water potentials in the soil are uniform, <strong>SUF</strong>. When a simple root hydraulic architecture was assumed, these two characteristics were sufficient to describe root water uptake from profiles with a non-uniform water distribution. This simplification gave accurate results when root characteristics were calculated directly from the root hydraulic architecture. In a next step, we investigate how the resistance to flow in the soil surrounding the root can be considered in a macroscopic root water uptake model. We specifically investigate whether the macroscopic representation of the flow in the root architecture, which predicts an effective xylem water potential at a certain soil depth, can be coupled with a model that describes the transfer from the soil to the root using a simplified representation of the root distribution in a certain soil layer, i.e. assuming a uniform root distribution.</p>

scholarly journals Effects of water deficit in two phenological stages on production of japanese cucumber cultived in greenhouse

2011 ◽  
Vol 31 (4) ◽  
pp. 676-686 ◽  
Author(s):  
Eduardo C. Oliveira ◽  
Jacinto de A. Carvalho ◽  
Wellington G. da Silva ◽  
Fátima C. Rezende ◽  
Willian F. de Almeida
Keyword(s):  
Soil Water ◽  
Water Deficit ◽  
Irrigation Management ◽  
Soil Water Potential ◽  
Phenological Stages ◽  
Cucumis Sativus L ◽  
Randomized Design ◽  
Minas Gerais State ◽  
Engineering Department ◽  
Four Levels

The experiment was performed in the experimental area of the Engineering Department Federal University of Lavras, Minas Gerais State, Brazil. It aimed at identifying the adequate irrigation management of the greenhouse-cultivated Japanese cucumber (Cucumis sativus L.). complete randomized design, with four levels of soil water potential (15; 30; 60 e 120 kPa) at two phenological phases (vegetative and reproductive), and 5 replications. Overall, the results showed decrease of yield according to increase of soil water potentials. During the reproductive stage, Japanese cucumber plants were more sensitive to water deficit, resulting in further decrease in yield compared to applied water deficit during the vegetative stage of the culture.

scholarly journals Effects of different biomass materials as a salt-isolation layer on water and salt migration in coastal saline soil

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11766
Author(s):  
Mao Yang ◽  
Runya Yang ◽  
Yanni Li ◽  
Yinghua Pan ◽  
Junna Sun ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Salt Concentration ◽  
Saline Soil ◽  
Soil Depth ◽  
Soil Layer ◽  
Thick Layer ◽  
Peat Layer ◽  
Salt Accumulation

The aim of this study was to find a material suited for the prevention of evaporative water loss and salt accumulation in coastal saline soils. One-dimensional vertical water infiltration and phreatic evaporation experiments were conducted using a silty loam saline soil. A 3-cm-thick layer of corn straw, biochar, and peat was buried at the soil depth of 20 cm, and a 6-cm-thick layer of peat was also buried at the same soil depth for comparison. The presence of the biochar layer increased the upper soil water content, but its ability to inhibit salt accumulation was poor, leading to a high salt concentration in the surface soil. The 3-cm-thick straw and 6-cm-thick peat layers were most effective to inhibit salt accumulation, which reduced the upper soil salt concentration by 96% and 93%, respectively. However, the straw layer strongly inhibited phreatic evaporation and resulted in low water content in the upper soil layer. Compared with the straw layer, the peat layer increased the upper soil water content. Thus, burying a 6-cm-thick peat layer in the coastal saline soil is the optimal strategy to retain water in the upper soil layer and intercept salt in the deeper soil layer.

A regionally explicit, global SWI calibration based on ISMN observations

2021 ◽  
Author(s):  
Manolis G. Grillakis
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Large Scale ◽  
Root Zone ◽  
Soil Depth ◽  
European Space Agency ◽  
Soil Layer ◽  
Added Value ◽  
Water Index ◽  
Soil Moisture Data

<p>Remote sensing has proven to be an irreplaceable tool for monitoring soil moisture. The European Space Agency (ESA), through the Climate Change Initiative (CCI), has provided one of the most substantial contributions in the soil water monitoring, with almost 4 decades of global satellite derived and homogenized soil moisture data for the uppermost soil layer. Yet, due to the inherent limitations of many of the remote sensors, only a limited soil depth can be monitored. To enable the assessment of the deeper soil layer moisture from surface remotely sensed products, the Soil Water Index (SWI) has been established as a convolutive transformation of the surface soil moisture estimation, under the assumption of uniform hydraulic conductivity and the absence of transpiration. The SWI uses a single calibration parameter, the T-value, to modify its response over time.</p><p>Here the Soil Water Index (SWI) is calibrated using ESA CCI soil moisture against in situ observations from the International Soil Moisture Network and then use Artificial Neural Networks (ANNs) to find the best physical soil, climate, and vegetation descriptors at a global scale to regionalize the calibration of the T-value. The calibration is then used to assess a root zone related soil moisture for the period 2001 – 2018.</p><p>The results are compared against the European Centre for Medium-Range Weather Forecasts, ERA5 Land reanalysis soil moisture dataset, showing a good agreement, mainly over mid-latitudes. The results indicate that there is added value to the results of the machine learning calibration, comparing to the uniform T-value. This work contributes to the exploitation of ESA CCI soil moisture data, while the produced data can support large scale soil moisture related studies.</p>

scholarly journals Water Stable Isotopes in an Alpine Setting of the Northeastern Tibetan Plateau

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 770 ◽  
Author(s):  
Xue Qiu ◽  
Mingjun Zhang ◽  
Shengjie Wang ◽  
Athanassios A. Argiriou ◽  
Rong Chen ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Soil Water ◽  
Water Cycle ◽  
Soil Depth ◽  
Soil Layer ◽  
Water Source ◽  
Hydrological Processes ◽  
Deep Soil ◽  
Monthly Basis ◽  
Mountainous Regions

Hydrological processes produce effects on water resources in inland mountainous regions. To perform a comprehensive investigation of the important segments of the water cycle, using the Qilian Mountains as a case study, precipitation, soil, plant, river, and groundwater were collected during the plant growing season of 2016. All samples were collected on a monthly basis, except precipitation, which was collected on a per event basis. The results showed that: the “temperature effect” was apparent, which suggested a drier climate background; there were differences in the slope and intercept of the local meteoric water line, using different regression methods; and the δ18O of soil water varied greatly in the topsoil, tended to be similar in the deep soil, and became increasingly depleted as the soil depth increased. The responses of the soil water isotopes to precipitation pulses had different boundaries. The major water source for Caragana Fabr. in no-precipitation month was located in the 0–30 cm soil layer, but was different in months when precipitation occurred. Overall, the findings from the stable isotopes provide insights into hydrological processes and offer a platform to understand mountainous water cycle in arid areas.

scholarly journals Experimental Study of the Effect of Controlled Drainage on Soil Water and Nitrogen Balance

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2241
Author(s):  
Niannian Yuan ◽  
Yujiang Xiong ◽  
Yalong Li ◽  
Baokun Xu ◽  
Fengli Liu
Keyword(s):  
Soil Moisture ◽  
Water Level ◽  
Soil Water ◽  
Nitrogen Balance ◽  
Field Experiments ◽  
Soil Depth ◽  
Soil Layer ◽  
Ammonia Nitrogen ◽  
Soil Water Storage ◽  
Control Water

Field experiments and micro test pit experiments are conducted at the Four Lake Watershed with a shallow groundwater table in the Hubei province of China in order to study the effect of controlled pipe drainage on soil moisture and nitrogen under different experiment scales. Soil moisture and nitrogen contents are continuously observed at the effective soil depth; water and nitrogen balance are calculated after several heavy rainfalls. The results showed that controlled pipe drainage significantly reduced the fluctuation of soil water content in the entire growth stage. There is a positive correlation between the soil moisture and the control water level in the test pits but no obvious correlation between them in the field experiments, which is related to the vertical and lateral recharge of groundwater in the field. After rainfall, soil organic matter mineralization was enhanced, and the control pipe drainage measures increased the relative content of soil mineralized ammonia nitrogen, which enhanced the stability of soil nitrogen and helped to reduce the loss of nitrogen. The calculation of soil water and nitrogen balance in the field and micro-area after rainfall showed that the soil water storage increased in the effective soil layer under the control water level of 30 cm and 50 cm after rainfall, and the amount of nitrogen mineralization was larger than that under the free drainage treatment.

scholarly journals Diurnal variation in the isotope composition of plant xylem water biases the depth of root-water uptake estimates

2020 ◽  
Author(s):  
Hannes P. T. De Deurwaerder ◽  
Marco D. Visser ◽  
Matteo Detto ◽  
Pascal Boeckx ◽  
Félicien Meunier ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Soil Water ◽  
Water Uptake ◽  
Isotope Composition ◽  
Soil Water Potential ◽  
Root Water Uptake ◽  
Stem Length ◽  
Sap Flux ◽  
Sap Flux Density ◽  
Water Isotopologues

Abstract. 1. Stable isotopologues of water are a widely used tool to derive the depth of root water uptake (RWU) in lignified plants. Uniform isotope composition of plant xylem water (i-H2O-xyl) along the stem length is a central assumption, which has never been properly evaluated. 2. We studied the effects of diurnal variation in RWU, sap flux density and various other soil and plant parameters on i-H2O-xyl within a plant using a mechanistic plant hydraulic model and empirical field observations from French Guiana and northwestern China. 3. Our model predicts significant i-H2O-xyl variation arising from diurnal RWU fluctuations and vertical soil water heterogeneity. Moreover, significant differences in i-H2O-xyl emerge between individuals with different sap flux densities. In line with model predictions, field data show excessive i-H2O-xyl variation during the day or along stem length ranging up to 25.2 ‰ in δ2H and 6.8 ‰ in δ18O, largely exceeding the measurement error range. 4. Our work show that the fundamental assumption of uniform i-H2O-xyl is violated both theoretically and empirically and therefore a real danger exists of significant biases when using stable water isotopologues to assess RWU. We propose to include monitoring of sap flow and soil water potential for more robust RWU depth estimates.

scholarly journals Soil-water characteristic curves for collapsing walls of Benggang in a typical granite area of southeast China

2021 ◽  
Author(s):  
Liting Zhang ◽  
Shujun Sun ◽  
Mengqi Lin ◽  
Kaijun Feng ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Depth ◽  
Characteristic Curve ◽  
Soil Layer ◽  
Particle Morphology ◽  
Red Soil ◽  
Southeast China ◽  
Average Value ◽  
Water Holding

The water content is a crucial factor in evaluating the causes of Benggang collapse. The soil–water characteristic curve (SWCC) is an important parameter for the quantitative study of soil water content. However, limited research has been carried out on the SWCCs of the Benggang soil profile. We studied two typical collapsing gullies in southeast China and conducted desorption experiments using a pressure plate extractor to analyze the SWCCs of the undisturbed soils of collapsing walls. The results show large variations in the SWCCs for different soil horizons of a collapsing wall that can be accurately fitted by the van Genuchten (VG) model (NSE≥0.90). With increasing soil depth, the a and θs parameters of the VG model first decrease and then increase, red soil layer had the highest a and θs (the average value of 0.046 and 0.369, respectively), whereas the n parameter of the VG model exhibits the opposite trend, sand soil layer had the highest n (the average value of 1.563). The θr parameter of the VG model decreases with increasing soil depth, red soil layer had the highest θr (the average value of 0.194). The red soil layer has the highest water-holding capacity, whereas the sandy soil and detritus layers have lower water-holding capacities. The SWCCs are related to the soil material composition, particle composition and porosity. The gravel content and the particle morphology (the aspect ratio, sphericity, and specific surface area) are also the significant influence factors for the SWCC that cannot be neglected. The difference among the SWCCs for the soil profiles of collapsing walls can be used to explain the mechanism for the collapse of collapsing wall. The results of this study provide a theoretical basis for understanding the process of the collapse of collapsing wall in Benggang in southeast China.

scholarly journals Natural 15N abundance in two nitrogen saturated forest ecosystems at Solling, Germany

2012 ◽  
Vol 49 (No. 11) ◽  
pp. 515-522 ◽  
Author(s):  
S. P Sah ◽  
R. Brumme
Keyword(s):  
Soil Water ◽  
Soil Depth ◽  
Mineral Soil ◽  
Soil Layer ◽  
Organic Soil ◽  
Soil Horizon ◽  
Nitrification Rate ◽  
Seepage Water ◽  
Natural Occurrence ◽  
N Enrichment

This research deals with a comparative study of two different N-saturated forests: 1. beech forest and 2. spruce forest at the same locality of \solling, Central Germany. The present results show that <sup>15</sup>N natural occurrence in the rainfall (both above and below canopy) at Solling site is similar (&delta;<sup>15</sup>N = &ndash;15&permil; to +19&permil;) to other sites of the world (such as NITREX sites, USA etc.). Furthermore, <sup>15</sup>N values in the soil water ranged from &ndash;4.32 (&plusmn; 2.09) to +5&permil; (&plusmn; 1.47), which also corresponds to NITREX sites and other sites of Europe and USA. In both forests, &delta;<sup>15</sup>N enrichment of both NH<sub>4</sub>-N and NO<sub>3</sub>-N showed a decreasing trend of their values from bulk precipitation to the upper soil layer, but increasing in the deeper soil layer again. An increase in the <sup>15</sup>N enrichment of soil water from upper soil depth to lower soil depth was observed in our study and it is assumed to be due to the strong net nitrification taking place in the upper layer (organic surface layer) of soil. The soils at both sites showed characteristic low (negative) &delta;<sup>15</sup>N values in the upper organic layers, strongly increasing to positive &delta;<sup>15</sup>N values in the mineral soil. In the lower depths of mineral soil horizons of both stands, an increase in &delta;<sup>15</sup>N values was found to culminate at +3 to +5&permil;. In contrast to the mineral soil horizon, in the organic soil horizon (0 to 6 cm depth) of both sites there was almost a similar or slight decrease in &delta;<sup>15</sup>N values with depth. This is attributed to the high nitrification rate in the organic soil horizon, resulting in excessive seepage water NO<sub>3</sub>-output at both sites (especially at the spruce site).

scholarly journals Will the conversion of evergreen and deciduous broad-leaved mixed forests to Chinese fir plantations affect the transportation of soil water?

2021 ◽  
Author(s):  
qi Chen ◽  
Yuanqiu Liu ◽  
Jiahui Huang ◽  
Yunhong Xie ◽  
Tianjun Bai ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Water Movement ◽  
Soil Depth ◽  
Soil Layer ◽  
Chinese Fir ◽  
Jiangxi Province ◽  
Natural Forests ◽  
Mixed Forests

The conversion of natural forests to planted forests has become a global trend, and the practice has wide-ranging effects on soil. This study aimed to explore the differences in soil water movement after the conversion of evergreen and deciduous broad-leaved mixed forests (natural forest, NF) to Chinese fir (Cunninghamia lanceolate (Lamb.) Hook.) plantations (CFP, 20–21 years old). Soil samples from five layers (0–5, 5–10, 10–20, 20–30, and 30–50 cm) were collected from NF and CFP before and after rainfall event in the Peng Chongjian watershed, Jiangxi Province. The physical properties of the soils, including the mean and coefficient of variation (CV) of soil moisture content and the soil particle composition, were determined in both forest types. The δD of soil water and the litter water-holding capacity were also measured. The results showed that the variation ranges of moisture content in each soil layer after the rainfall was 21.13%–49.40% in CFP and 21.33%–43.87% in NF. There were no significant differences in soil bulk density or porosity; the clay and silt contents were significantly increased in topsoil, while the sand was significantly decreased (P < 0.05). After the rainfall, soil water in CFP responded more promptly than NF. In the process of infiltration, the contribution of rainfall to soil moisture gradually decreased with increasing soil depth. Topsoil (0–5 cm) in NF responded promptly to rainfall, but the response showed a lag effect with the increase of soil depth. With the extension of infiltration time, the contribution of precipitation to deep soil gradually increased. The results showed that the soil did not degrade after the conversion of NF to CFP, a significant guiding result for plantation cultivation.

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