scholarly journals Comparing the Deep Root Growth and Water Uptake of Intermediate Wheatgrass (Kernza®) to Alfalfa.

2021 ◽  
Author(s):  
Corentin Clement ◽  
Joost Sleiderink ◽  
Simon Fiil Svane ◽  
Abraham George Smith ◽  
Efstathios Diamantopoulos ◽  
...  
Keyword(s):  
Root Growth ◽  
Soil Water ◽  
Water Uptake ◽  
Soil Depth ◽  
Deep Soil ◽  
Perennial Crops ◽  
Intermediate Wheatgrass ◽  
Deep Root ◽  
Grain Crop ◽  
Perennial Grain

Abstract AimsWater is the most important yield-limiting factor worldwide and drought is predicted to increase in the future. Perennial crops with more extensive and deep root systems could access deep stored water and build resilience to water shortage. In the context of human nutrition, perennial grain crops are very interesting. However, it is still questionable whether they are effective in using subsoil water. We compared intermediate wheatgrass (Kernza®) Thinopyrum intermedium, a perennial grain crop, to alfalfa Medicago sativa, a perennial forage, for subsoil root growth and water uptake.MethodsUsing TDR sensors, deuterium tracer labelling, minirhizotrons and the Hydrus-1D model we characterised the root distribution and water uptake patterns of these two perennial crops during two cropping seasons under field conditions down to 2.5 m soil depth.ResultsBoth crops grew roots down to 2.0 m depth that were active in water uptake but alfalfa was deeper rooted than intermediate wheatgrass. All experimental methods concluded that alfalfa used more water from below 1.0 m depth than intermediate wheatgrass. However, simulations predicted that intermediate wheatgrass used more than 20 mm of water after anthesis from below 1 m soil depth. Simulations confirmed the advantage of deep roots in accessing deep soil water under drought.ConclusionsIn regions with high groundwater recharge, growing deep-rooted perennial crops have great potential to exploit deep soil water that is often left unused. However, the road to a profitable perennial grain crop is still long and breeding intermediate wheatgrass (Kernza®) cultivars for increased root growth at depth seems to be a worthy investment for the development of more drought tolerant cultivars.

scholarly journals Soil Water Uptake by Amazonian Trees and Simulation of Impacts on Energy Fluxes and Soil Moisture Dynamics at the LBA Flux Towers

2021 ◽  
Author(s):  
Paulo Rodrigo Zanin
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Uptake ◽  
Amazon Basin ◽  
Deep Soil ◽  
Tree Roots ◽  
Soil Layers ◽  
Deep Root ◽  
Set Up ◽  
Amazonian Trees

Abstract Observational and modeling studies show that a deeper soil water uptake by tree roots is required for evapotranspiration in the Amazon Basin. Therefore, this study performed three numerical modeling experiments with different depths of soil water uptake by Amazonian tree roots using the Eta/CPTEC regional climate model. In the “Control” and “Deep Soil Shallow Root” experiments the depth of soil water uptake by tree roots is set up with 2 m, while in the “Deep Soil Deep Root” experiment this depth is set up with 7.2 m, according to the observational studies. The energy balance at the LBA flux towers is better simulated in the “Deep Soil Deep Root” experiment than in other experiments. Moreover, with the “Deep Soil Deep Root” experiment the seasonality of evapotranspiration is reduced in the regions where there is strong seasonality of precipitation, while the seasonality of moisture is reduced in shallow soil layers and increases in the deeper soil layers. In addition, in the regions with strong seasonality of precipitation the deeper soil layers have an inter-annual hydrological memory, and in all regions the soil moisture memory is inversely related to the amount of precipitation, with different behaviors in each soil layer. In conclusion, the deeper soil water uptake by the Amazonian trees is important for the energy balance and soil moisture dynamics in the Amazon Basin.

scholarly journals Genotypic variation in soil water use and root distribution and their implications for drought tolerance in chickpea

2017 ◽  
Vol 44 (2) ◽  
pp. 235 ◽  
Author(s):  
Ramamoorthy Purushothaman ◽  
Lakshmanan Krishnamurthy ◽  
Hari D. Upadhyaya ◽  
Vincent Vadez ◽  
Rajeev K. Varshney
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Water Uptake ◽  
Root Distribution ◽  
Root Length Density ◽  
Soil Depth ◽  
Genotypic Variation ◽  
Yield Losses ◽  
Total Water ◽  
Deep Soil

Chickpeas are often grown under receding soil moisture and suffer ~50% yield losses due to drought stress. The timing of soil water use is considered critical for the efficient use of water under drought and to reduce yield losses. Therefore the root growth and the soil water uptake of 12 chickpea genotypes known for contrasts in drought and rooting response were monitored throughout the growth period both under drought and optimal irrigation. Root distribution reduced in the surface and increased in the deep soil layers below 30 cm in response to drought. Soil water uptake was the maximum at 45–60 cm soil depth under drought whereas it was the maximum at shallower (15–30 and 30–45 cm) soil depths when irrigated. The total water uptake under drought was 1-fold less than optimal irrigation. The amount of water left unused remained the same across watering regimes. All the drought sensitive chickpea genotypes were inferior in root distribution and soil water uptake but the timing of water uptake varied among drought tolerant genotypes. Superiority in water uptake in most stages and the total water use determined the best adaptation. The water use at 15–30 cm soil depth ensured greater uptake from lower depths and the soil water use from 90–120 cm soil was critical for best drought adaptation. Root length density and the soil water uptake across soil depths were closely associated except at the surface or the ultimate soil depths of root presence.

Water balance changes in a crop sequence with lucerne

2001 ◽  
Vol 52 (2) ◽  
pp. 247 ◽  
Author(s):  
F. X. Dunin ◽  
C. J. Smith ◽  
S. J. Zegelin ◽  
R. Leuning
Keyword(s):  
Soil Water ◽  
Water Uptake ◽  
Soil Depth ◽  
Water Storage ◽  
Growing Season ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Root Extension ◽  
Annual Crops ◽  
Lower Productivity

In a detailed study of soil water storage and transport in a sequence of 1 year wheat and 4 years of lucerne, we evaluated drainage under the crop and lucerne as well as additional soil water uptake achieved by the subsequent lucerne phase. The study was performed at Wagga Wagga on a gradational clay soil between 1993 and 1998, during which there was both drought and high amounts of drainage (>10% of annual rainfall) from the rotation. Lucerne removed an additional 125 mm from soil water storage compared with wheat (root-zone of ~1 m), leading to an estimated reduction in drainage to 30–50% of that of rotations comprising solely annual crops and/or pasture. This additional soil water uptake by lucerne was achieved through apparent root extension of 2–2.5 m beyond that of annual crops. It was effective in generating a sink for soil water retention that was about double that of annual crops in this soil. Successful establishment of lucerne at 30 plants/m2 in the first growing season of the pasture phase was a requirement for this root extension. Seasonal water use by lucerne tended to be similar to that of crops in the growing season between May and September, because plant water uptake was confined to the top 1 m of soil. Uptake of water from the subsoil was intermittent over a 2-year period following its successful winter establishment. In each of 2 annual periods, uptake below 1 m soil depth began late in the growing season and terminated in the following autumn. Above-ground dry matter production of lucerne was lower than that by crops grown in the region despite an off-season growth component that was absent under fallow conditions following cropping. This apparent lower productivity of lucerne could be traced in part to greater allocation of assimilate to roots and also to late peak growth rates at high temperatures, which incurred a penalty in terms of lower transpiration efficiency. The shortfall in herbage production by lucerne was offset with the provision of timely, high quality fodder during summer and autumn. Lucerne conferred indirect benefits through nitrogen supply and weed control. Benefits and penalties to the agronomy and hydrology of phase farming systems with lucerne are discussed.

scholarly journals A mechanistic model for electrical conduction in soil–root continuum: a virtual rhizotron study

2018 ◽  
Author(s):  
Sathyanarayan Rao ◽  
Félicien Meunier ◽  
Solomon Ehosioke ◽  
Nolwenn Lesparre ◽  
Andreas Kemna ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Root Growth ◽  
Water Content ◽  
Soil Water ◽  
Water Uptake ◽  
Numerical Study ◽  
Root Segments ◽  
Bulk Electrical Conductivity ◽  
The Impact

Abstract. Electrical Resistivity Tomography (ERT) has become an important tool to study soil water fluxes in cropped field. ERT results translates to water content via empirical pedophysical relations that take soil physical properties into account, usually ignoring the impact of roots. Studies shows high root dense soils behaves quite differently than less root dense soils in terms of bulk electrical conductivity. Yet, we do not completely understand the impact of root segments on the ERT measurements. In this numerical study, we coupled an electrical model with a plant-soil water flow model to investigate the impact of plant root growth and water uptake on the ERT virtual experiment. The electrical properties of roots were explicitly accounted in the finite element mesh and we obtained the electrical conductivities of root segments by conducting specific experiments on real maize plants. The contrast between electrical conductivity of roots and soil depends on factors such as root density, irrigation, root age, and root water uptake pattern. Root growth and water uptake processes thus affect this contrast together with the soil electrical properties. Model results indicate a non-negligible anisotropy in bulk electrical conductivity induced by root processes. We see a greater anisotropy in a sandy medium when compared to a loamy medium. We find that the water uptake process dominates the bulk electrical properties. The Gauss-Newton type ERT inversion of virtual rhizotron data demonstrate that, when root-soil electrical conductivity contrasts are high, it can lead to error in water content estimates since the electrical conductivity is partly due to root. Thus, incorporating the impact of root in the pedophysical relations is very important to interpret ERT results directly as water content.

scholarly journals Modelling the artificial forest (<i>Robinia pseudoacacia</i> L.) root–soil water interactions in the Loess Plateau, China

2022 ◽  
Vol 26 (1) ◽  
pp. 17-34
Author(s):  
Hongyu Li ◽  
Yi Luo ◽  
Lin Sun ◽  
Xiangdong Li ◽  
Changkun Ma ◽  
...  
Keyword(s):  
Root Growth ◽  
Soil Water ◽  
Loess Plateau ◽  
Water Uptake ◽  
Growth Models ◽  
Robinia Pseudoacacia ◽  
Rooting Depth ◽  
Climatic Data ◽  
Forest Site ◽  
The Loess Plateau

Abstract. Plant root–soil water interactions are fundamental to vegetation–water relationships. Soil water availability and distribution impact the temporal–spatial dynamics of roots and vice versa. In the Loess Plateau (LP) of China, where semi-arid and arid climates prevail and deep loess soil dominates, drying soil layers (DSLs) have been extensively reported in artificial forestland. While the underlying mechanisms that cause DSLs remain unclear, they hypothetically involve root–soil water interactions. Although available root growth models are weak with respect to simulating the rooting depth, this study addresses the hypothesis of the involvement of root–soil water interactions in DSLs using a root growth model that simulates both the dynamic rooting depth and fine-root distribution, coupled with soil water, based on cost–benefit optimization. Evaluation of field data from an artificial black locust (Robinia pseudoacacia L.) forest site in the southern LP positively proves the model's performance. Further, a long-term simulation, forced by a 50-year climatic data series with varying precipitation, was performed to examine the DSLs. The results demonstrate that incorporating the dynamic rooting depth into the current root growth models is necessary to reproduce soil drying processes. The simulations revealed that the upper boundary of the DSLs fluctuates strongly with infiltration events, whereas the lower boundary extends successively with increasing rooting depth. Most infiltration was intercepted by the top 2.0 m layer, which was the most active zone of infiltration and root water uptake. Below this, the percentages of fine roots (5.0 %) and water uptake (6.2 %) were small but caused a persistently negative water balance and consequent DSLs. Therefore, the proposed root–water interaction approach succeeded in revealing the intrinsic properties of DSLs; their persistent extension and the lack of an opportunity for recovery from the drying state may adversely affect the implementation of artificial afforestation in this region as well as in other regions with similar climates and soils.

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.

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