Ad Hoc Modeling of Root Zone Soil Water with Landsat Imagery and Terrain and Soils Data

Water scarcity and quality degradation represent real threats to economic, social, and environmental development of arid and semi-arid regions. Drip irrigation associated to Deficit Irrigation (DI) has been investigated as a water saving technique. Yet its environmental impacts on soil and groundwater need to be gone into in depth especially when using brackish irrigation water. Soil water content and salinity were monitored in a fully drip irrigated potato plot with brackish water (4.45 dSm−1) in semi-arid Tunisia. The HYDRUS-1D model was used to investigate the effects of different irrigation regimes (deficit irrigation (T1R, 70% ETc), full irrigation (T2R, 100% ETc), and farmer’s schedule (T3R, 237% ETc) on root water uptake, root zone salinity, and solute return flows to groundwater. The simulated values of soil water content (θ) and electrical conductivity of soil solution (ECsw) were in good agreement with the observation values, as indicated by mean RMSE values (≤0.008 m3·m−3, and ≤0.28 dSm−1 for soil water content and ECsw respectively). The results of the different simulation treatments showed that relative yield accounted for 54%, 70%, and 85.5% of the potential maximal value when both water and solute stress were considered for deficit, full. and farmer’s irrigation, respectively. Root zone salinity was the lowest and root water uptake was the same with and without solute stress for the treatment corresponding to the farmer’s irrigation schedule (273% ETc). Solute return flows reaching the groundwater were the highest for T3R after two subsequent rainfall seasons. Beyond the water efficiency of DI with brackish water, long term studies need to focus on its impact on soil and groundwater salinization risks under changing climate conditions.

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Measurement of soil water flux in andisols at a depth below a root zone of about 1 Meter

Soil Science & Plant Nutrition ◽

10.1080/00380768.1994.10414286 ◽

1994 ◽

Vol 40 (1) ◽

pp. 137-147 ◽

Cited By ~ 9

Author(s):

Shuichi Hasegawa ◽

Seiko Osozawa ◽

Hideto Ueno

Keyword(s):

Soil Water ◽

Root Zone ◽

Water Flux ◽

Soil Water Flux

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A MODEL FOR ESTIMATING ACTUAL EVAPOTRANSPIRATION FROM POTENTIAL EVAPOTRANSPIRATION

Hydrology Research ◽

10.2166/nh.1975.0012 ◽

1975 ◽

Vol 6 (3) ◽

pp. 170-188 ◽

Cited By ~ 212

Author(s):

K. J. KRISTENSEN ◽

S. E. JENSEN

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Root Zone ◽

Potential Evapotranspiration ◽

Actual Evapotranspiration ◽

Vegetation Density ◽

Rainfall Distribution ◽

Sugar Beets

A model for calculating the daily actual evapotranspiration based on the potential one is presented. The potential evapotranspiration is reduced according to vegetation density, water content in the root zone, and the rainfall distribution. The model is tested by comparing measured (EAm) and calculated (EAc) evapotranspirations from barley, fodder sugar beets, and grass over a four year period. The measured and calculated values agree within 10 %. The model also yields information on soil water content and runoff from the root zone.

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The Effect of Dry Pegging Zone Soil on Pod Formation of Florunner Peanut1

Peanut Science ◽

10.3146/i0095-3679-24-1-6 ◽

1997 ◽

Vol 24 (1) ◽

pp. 19-24 ◽

Cited By ~ 6

Author(s):

P. J. Sexton ◽

J. M. Bennett ◽

K. J. Boote

Keyword(s):

Drought Stress ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Deficit ◽

Growth Rates ◽

Root Zone ◽

Soil Water Deficit ◽

Seed Growth ◽

Pod Development

Abstract Peanut (Arachis hypogaea L.) fruit growth is sensitive to surface soil (0-5 cm) conditions due to its subterranean fruiting habit. This study was conducted to determine the effect of soil water content in the pegging zone (0-5 cm) on peanut pod growth rate and development. A pegging-pan-root-tube apparatus was used to separately control soil water content in the pegging and root zone for greenhouse trials. A field study also was conducted using portable rainout shelters to create a soil water deficit. Pod phenology, pod and seed growth rates, and final pod and seed dry weights were determined. In greenhouse studies, dry pegging zone soil delayed pod and seed development. In the field, soil water deficits in the pegging and root zone decreased pod and seed growth rates by approximately 30% and decreased weight per seed from 563 to 428 mg. Pegs initiating growth during drought stress demonstrated an ability to suspend development during the period of soil water deficit and to re-initiate pod development after the drought stress was relieved.

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From near-surface to root-zone soil moisture using an exponential filter: an assessment of the method based on in-situ observations and model simulations

Hydrology and Earth System Sciences ◽

10.5194/hess-12-1323-2008 ◽

2008 ◽

Vol 12 (6) ◽

pp. 1323-1337 ◽

Cited By ~ 261

Author(s):

C. Albergel ◽

C. Rüdiger ◽

T. Pellarin ◽

J.-C. Calvet ◽

N. Fritz ◽

...

Keyword(s):

Soil Moisture ◽

Soil Water ◽

Surface Soil ◽

Root Zone ◽

Synthetic Data ◽

Surface Soil Moisture ◽

Data Set ◽

Water Index ◽

In Situ Observations

Abstract. A long term data acquisition effort of profile soil moisture is under way in southwestern France at 13 automated weather stations. This ground network was developed in order to validate remote sensing and model soil moisture estimates. In this paper, both those in situ observations and a synthetic data set covering continental France are used to test a simple method to retrieve root zone soil moisture from a time series of surface soil moisture information. A recursive exponential filter equation using a time constant, T, is used to compute a soil water index. The Nash and Sutcliff coefficient is used as a criterion to optimise the T parameter for each ground station and for each model pixel of the synthetic data set. In general, the soil water indices derived from the surface soil moisture observations and simulations agree well with the reference root-zone soil moisture. Overall, the results show the potential of the exponential filter equation and of its recursive formulation to derive a soil water index from surface soil moisture estimates. This paper further investigates the correlation of the time scale parameter T with soil properties and climate conditions. While no significant relationship could be determined between T and the main soil properties (clay and sand fractions, bulk density and organic matter content), the modelled spatial variability and the observed inter-annual variability of T suggest that a weak climate effect may exist.

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Water and salt transport in daily irrigated root zone.

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v35i3.16734 ◽

1987 ◽

Vol 35 (3) ◽

pp. 395-406

Author(s):

C. Dirksen

Keyword(s):

Soil Water ◽

Water Uptake ◽

Gamma Ray ◽

Root Zone ◽

Root Water Uptake ◽

Salt Transport ◽

Soil Water Retention ◽

Transport Models ◽

Leaching Fraction ◽

Water Contents

With closed, high-frequency irrigation systems, the water supply can be tailored to the instant needs of plants. To be able to do this optimally, it is necessary to understand how plants interact with their environment. To study water uptake under a variety of non-uniform conditions in the root zone, lucerne was grown in laboratory soil columns with automated gamma ray attenuation, tensiometer and salinity sensor equipment to measure soil water contents, pressure potentials and osmotic potentials, respectively. The columns were irrigated with water of different salinity at various frequencies and leaching fractions. This paper presents results obtained in a column irrigated daily with water of conductivity 0.33 S/m (h0 = -13.2 m) at a target leaching fraction of 0.08. This includes the drying and wetting patterns under daily irrigations in deficit and excess of evapotranspiration, respectively. After 230 days the salination of the column had still not reached a steady state. Salinity increased rapidly with depth and root water uptake was shallow for the deep-rooting lucerne. Water and salt transport under daily irrigation cannot be described without taking hysteresis of soil water retention into account. The data presented are suitable for testing various water uptake models, once numerical water and salt transport models of the required complexity are operational. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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Simulating measurable ecosystem carbon and nitrogen dynamics with the mechanistically-defined MEMS 2.0 model

10.5194/bg-2020-493 ◽

2021 ◽

Author(s):

Yao Zhang ◽

Jocelyn M. Lavallee ◽

Andy D. Robertson ◽

Rebecca Even ◽

Stephen M. Ogle ◽

...

Keyword(s):

Organic Matter ◽

Soil Water ◽

Root Zone ◽

Ecosystem Respiration ◽

Gross Primary Production ◽

Total N ◽

Calibration And Validation ◽

Biogeochemical Models ◽

Lower Accuracy ◽

C Stocks

Abstract. For decades, predominant soil biogeochemical models have used conceptual soil organic matter (SOM) pools and only simulated them to a shallow depth in soil. Efforts to overcome these limitations have prompted the development of new generation SOM models, including MEMS 1.0, which represents measurable biophysical SOM fractions, over the entire root zone, and embodies recent understanding of the processes that govern SOM dynamics. Here we present the result of continued development of the MEMS model, version 2.0. MEMS 2.0 is a full ecosystem model with modules simulating plant growth with above and below-ground inputs, soil water, and temperature by layer, decomposition of plant inputs and SOM, and mineralization and immobilization of nitrogen (N). The model simulates two commonly measured SOM pools – particulate and mineral-associated organic matter (POM and MAOM), respectively. We present results of calibration and validation of the model with several grassland sites in the U.S. MEMS 2.0 generally captured the soil carbon (C) stocks (R2 of 0.89 and 0.6 for calibration and validation, respectively) and their distributions between POM and MAOM throughout the entire soil profile. The simulated soil N matches measurements but with lower accuracy (R2 of 0.73 and 0.31 for calibration and validation of total N in SOM, respectively) than for soil C. Simulated soil water and temperature were compared with measurements and the accuracy is comparable to the other commonly used models. The seasonal variation in gross primary production (GPP; R2 = 0.83), ecosystem respiration (ER; R2 = 0.89), net ecosystem exchange (NEE; R2 = 0.67), and evapotranspiration (ET; R2 = 0.71) were well captured by the model. We will further develop the model to represent forest and agricultural systems and improve it to incorporate new understanding of SOM decomposition.

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Rate and Timing of Meat and Bone Meal Applications Influence Growth, Yield, and Soil Water Nitrate Concentrations in Sweet Corn Production

Agronomy ◽

10.3390/agronomy11101945 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1945

Author(s):

Tiare Silvasy ◽

Amjad A. Ahmad ◽

Koon-Hui Wang ◽

Theodore J. K. Radovich

Keyword(s):

Soil Water ◽

Sweet Corn ◽

Root Zone ◽

Organic Fertilizer ◽

Growth Yield ◽

Split Application ◽

Meat And Bone Meal ◽

Bone Meal ◽

Corn Production ◽

Application Rates

Using local resources and minimizing environmental impacts are two important components of sustainable agriculture. Meat and bone meal (MBM), tankage, is a locally produced organic fertilizer. This study was conducted to investigate the response of sweet corn (Zea mays L. var. saccharata Stuart.) and soil water nitrate (NO3-N) concentration to MBM application at two locations, Waimānalo and Poamoho, on the island of O’ahu. The objectives were to determine effects of six application rates (0, 112, 224, 336, 448 and 672 kg N ha−1) and two application timings (preplant and split application) on: (1) sweet corn growth, yield, and quality, and (2) soil water nitrate concentration within and below the root zone. The split-plot was designed as four replicates randomly arranged in a complete block. Plant growth of roots and shoots, yield, and relative leaf chlorophyll content of sweet corn increased with increasing application rates of MBM in both locations. At Poamoho, yield was 13.6% greater in preplant versus split application. Nitrate-nitrogen losses were reduced by 20% at Waimānalo and 40% at Poamoho when MBM was applied in split applications. These findings suggest that MBM is an effective nitrogen source for sweet corn and a split application of MBM may reduce the potential for pollution.

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A decreasing trend in global soil water storage from 1981 to 2017

10.5194/egusphere-egu21-5756 ◽

2021 ◽

Author(s):

XinRui Luo ◽

Shaoda Li ◽

Wunian Yang ◽

Liang Liu ◽

Xiaolu Tang

Keyword(s):

Soil Water ◽

Water Loss ◽

Root Zone ◽

Carbon Sink ◽

Temporal Trends ◽

Water Storage ◽

Terrestrial Ecosystems ◽

Environmental Drivers ◽

Soil Water Storage ◽

Soil Drought

Soil water storage serves as a vital resource of the terrestrial ecosystems, and it can significantly influence water cycle and carbon cycling with the frequent occurrence of soil drought induced by land-atmosphere feedbacks. However, there are high variations and uncertainties of root zone soil water storage. This study applied comparison map profile (CMP), Mann-Kendall test, Theil-Sen estimate and partial correlation analysis to (1) estimate the global root zone (0~1 m) soil water storage, (2) and investigate the spatial and temporal patterns from 1981 to 2017 at the global scale, (3) and their relationships with environmental drivers (precipitation, temperature, potential evaportranspiration) using three soil moisture (SM) products &#8211; ERA-5, GLDAS and MERRA-2. Globally, the average annual soil water storage from 1981 to 2017 varied significantly, ranging from 138.3 (100 Pg a-1, 1 Pg = 1015 g) in GLDAS to 342.6 (100 Pg a-1) in ERA-5. Soil water storage of the three SM products consistently showed a decreasing trend. However, the temporal trend of soil water storage among different climate zones was different, showing a decreasing trend in tropical, temperate and cold zones, but an increasing trend in polar regions. On the other hand, temporal trends in arid regions differed from ERA-5, GLDAS and MERRA-2. Spatially, the SM products differed greatly, particularly for boreal areas with D value higher for 2500 Mg ha-1 a-1 and CC value lower for -0.2 between GLDAS and MERRA-2. Over 1981 to 2017, water storage of more than 50% of the global land area suffered from a decreasing trend, especially in Africa and Northeastern of China. Precipitation was the main dominated driver for variation of soil water storage, and distribution varied in different SM products. In conclusion, a global decreasing trend in soil water storage indicate a water loss from soils, and how the water loss affecting carbon sink in terrestrial ecosystems under ongoing climate change needs further investigation.

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