scholarly journals Hydrologic regulation of plant rooting depth

2017 ◽  
Vol 114 (40) ◽  
pp. 10572-10577 ◽  
Author(s):  
Ying Fan ◽  
Gonzalo Miguez-Macho ◽  
Esteban G. Jobbágy ◽  
Robert B. Jackson ◽  
Carlos Otero-Casal
Keyword(s):  
Root Water Uptake ◽  
Rooting Depth ◽  
Infiltration Depth ◽  
Deep Soil ◽  
Deep Roots ◽  
High Productivity ◽  
Local Soil ◽  
Bedrock Weathering ◽  
Hydrologic Regulation ◽  
Topographic Positions

Plant rooting depth affects ecosystem resilience to environmental stress such as drought. Deep roots connect deep soil/groundwater to the atmosphere, thus influencing the hydrologic cycle and climate. Deep roots enhance bedrock weathering, thus regulating the long-term carbon cycle. However, we know little about how deep roots go and why. Here, we present a global synthesis of 2,200 root observations of >1,000 species along biotic (life form, genus) and abiotic (precipitation, soil, drainage) gradients. Results reveal strong sensitivities of rooting depth to local soil water profiles determined by precipitation infiltration depth from the top (reflecting climate and soil), and groundwater table depth from below (reflecting topography-driven land drainage). In well-drained uplands, rooting depth follows infiltration depth; in waterlogged lowlands, roots stay shallow, avoiding oxygen stress below the water table; in between, high productivity and drought can send roots many meters down to the groundwater capillary fringe. This framework explains the contrasting rooting depths observed under the same climate for the same species but at distinct topographic positions. We assess the global significance of these hydrologic mechanisms by estimating root water-uptake depths using an inverse model, based on observed productivity and atmosphere, at 30″ (∼1-km) global grids to capture the topography critical to soil hydrology. The resulting patterns of plant rooting depth bear a strong topographic and hydrologic signature at landscape to global scales. They underscore a fundamental plant–water feedback pathway that may be critical to understanding plant-mediated global change.

RESISTANCE TO MILDEW OF SELECTION FAMILY OF RED CURRANT THE BELAYA POTAPENKO × № 1426-21-80

1970 ◽  
pp. 38-40
Author(s):  
O. O. Kalinina ◽  
O. D. Golyaeva ◽  
O. V. Panfilova ◽  
А. V. Pikunova
Keyword(s):  
Powdery Mildew ◽  
Field Resistance ◽  
Disease Development ◽  
Artificial Infection ◽  
Sources Of Resistance ◽  
Climate Conditions ◽  
High Productivity ◽  
Local Soil ◽  
The Family ◽  
Red Currant

Powdery mildew is one of the most harmful fungal diseases that causes economically significant damage to berry plantations. The disease is common in all areas of currant cultivation in the Russian Federation. In this regard, in modern conditions of intensive berry growing, the problem of breeding cultivars that are highly resistant to diseases and pests becomes urgent. Breeders have a difficult task to combine the adaptive potential of the cultivar with its annual high productivity and resistance to biotic environmental factors. When studying the adaptability of introduced cultivars of red currant and selected forms of the Institute to local soil and climate conditions, the following cultivars were identified as sources of economic and useful characteristics and involved in selection: ‘Belaya Potapenko’ as a complex source of resistance powdery mildew and high marketable and taste qualities of berries; SS 1426-21-80 as a source of high productivity and long racemes (raceme length 11-13 cm; up to 20 berries in the raceme). On their base the selection family of red currant has been developed: Belaya Potapenko × ♂SS 1426-21-80. The study of data on the destruction of hybrid seedlings of the selection family by powdery mildew showed that in epiphytotic conditions, the percentage of intensity of the disease development varies over the periods of screening from 0.2% in May to 20.4% in June. Such indicators served as a prerequisite for conducting a comparative test of breeding material in the field under artificial infection with powdery mildew. After artificial infection on the background of epiphytosis, the rate of intensity of the disease development increased slightly and amounted to 35.6% for the family. There were 30 highly resistant seedlings in the family, 10 of which have remained stable and highly resistant since 2018. In these plants we can assume the presence of the so-called field resistance, controlled by polygens, each of which does not give a visible effect of stability, but with different combinations determines one or another of its degree. Highly resistant seedlings will be used in further breeding studies to identify new sources of resistance to powdery mildew.

scholarly journals How to put plant root uptake into a soil water flow model

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 43
Author(s):  
Xuejun Dong
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Water Uptake ◽  
Root Distribution ◽  
Plant Root ◽  
Root Water Uptake ◽  
Root Uptake ◽  
Water Dynamics ◽  
Rooting Depth ◽  
Plant Root Uptake

The need for improved crop water use efficiency calls for flexible modeling platforms to implement new ideas in plant root uptake and its regulation mechanisms. This paper documents the details of modifying a soil infiltration and redistribution model to include (a) dynamic root growth, (b) non-uniform root distribution and water uptake, (c) the effect of water stress on plant water uptake, and (d) soil evaporation. The paper also demonstrates strategies of using the modified model to simulate soil water dynamics and plant transpiration considering different sensitivity of plants to soil dryness and different mechanisms of root water uptake. In particular, the flexibility of simulating various degrees of compensated uptake (whereby plants tend to maintain potential transpiration under mild water stress) is emphasized. The paper also describes how to estimate unknown root distribution and rooting depth parameters by the use of a simulation-based searching method. The full documentation of the computer code will allow further applications and new development.

scholarly journals Disentangling temporal and population variability in plant root water uptake from stable isotopic analysis: when rooting depth matters in labeling studies

2020 ◽  
Vol 24 (6) ◽  
pp. 3057-3075 ◽  
Author(s):  
Valentin Couvreur ◽  
Youri Rothfuss ◽  
Félicien Meunier ◽  
Thierry Bariac ◽  
Philippe Biron ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Water Content ◽  
Soil Water ◽  
Physical Model ◽  
Transpiration Rate ◽  
Temporal Dynamics ◽  
Plant Root ◽  
Root Water Uptake ◽  
Rooting Depth ◽  
Stable Isotopic

Abstract. Isotopic labeling techniques have the potential to minimize the uncertainty of plant root water uptake (RWU) profiles estimated using multisource (statistical) modeling by artificially enhancing the soil water isotopic gradient. On the other end of the modeling continuum, physical models can account for hydrodynamic constraints to RWU if simultaneous soil and plant water status data are available. In this study, a population of tall fescue (Festuca arundinacea cv. Soni) was grown in amacro-rhizotron and monitored for a 34 h long period following the oxygen stable isotopic (18O) labeling of deep soil water. Aboveground variables included tiller and leaf water oxygen isotopic compositions (δtiller and δleaf, respectively) as well as leaf water potential (ψleaf), relative humidity, and transpiration rate. Belowground profiles of root length density (RLD), soil water content, and isotopic composition were also sampled. While there were strong correlations between hydraulic variables as well as between isotopic variables, the experimental results underlined the partial disconnect between the temporal dynamics of hydraulic and isotopic variables. In order to dissect the problem, we reproduced both types of observations with a one-dimensional physical model of water flow in the soil–plant domain for 60 different realistic RLD profiles. While simulated ψleaf followed clear temporal variations with small differences across plants, as if they were “onboard the same roller coaster”, simulated δtiller values within the plant population were rather heterogeneous (“swarm-like”) with relatively little temporal variation and a strong sensitivity to rooting depth. Thus, the physical model explained the discrepancy between isotopic and hydraulic observations: the variability captured by δtiller reflected the spatial heterogeneity in the rooting depth in the soil region influenced by the labeling and may not correlate with the temporal dynamics of ψleaf. In other words, ψleaf varied in time with transpiration rate, while δtiller varied across plants with rooting depth. For comparison purposes, a Bayesian statistical model was also used to simulate RWU. While it predicted relatively similar cumulative RWU profiles, the physical model could differentiate the spatial from the temporal dynamics of the isotopic composition. An important difference between the two types of RWU models was the ability of the physical model to simulate the occurrence of hydraulic lift in order to explain concomitant increases in the soil water content and the isotopic composition observed overnight above the soil labeling region.

Water relations of winter wheat: 2. Soil water relations

1978 ◽  
Vol 91 (1) ◽  
pp. 103-116 ◽  
Author(s):  
P. J. Gregory ◽  
M. McGowan ◽  
P. V. Biscoe
Keyword(s):  
Winter Wheat ◽  
Water Potential ◽  
Soil Water ◽  
Water Relations ◽  
Unit Length ◽  
Soil Water Potential ◽  
Rooting Depth ◽  
Wheat Crop ◽  
Deep Roots ◽  
Volumetric Soil Water Content

SummaryVolumetric soil water content and soil water potential were measured beneath a winter wheat crop during the 1975 growing season. Almost no rain fell between mid-May and mid-July and the soil dried continuously until the potential was less than – 20 bars to a depth of 80 cm. Evaporation was separated from drainage by denning an ‘effective rooting depth’ at which the hydraulic gradient was zero.Rates of water uptake per unit length of root (inflow) were calculated for the whole soil profile and for individual soil layers. Generally, inflow decreased throughout the period of measurement from a maximum of 2·5 × 10–3 to a minimum of 0·66 × 10–3 ml water/cm root/day. Values in individual layers were frequently higher than the mean inflow and the importance of a few deep roots in taking up water during a dry season is emphasized. A similar correlation between inflow and soil water potential was found to apply for the 0–30 cm and 30–60 cm layers during the period of continual soil drying. This relationship represents the maximum inflow measured at a given soil water potential; actual inflow at any particular time depends upon the interrelationship of atmospheric demand, soil water potential and the distribution of root length in the soil.

The Nivolet CZ Ecosystem Observatory reveals rapid soil development in recently deglaciated alpine environments: Biotic weathering is the likely culprit

2020 ◽  
Author(s):  
Ilaria Baneschi ◽  
Ashlee Dere ◽  
Emma Aronson ◽  
Ramona Balint ◽  
Sharon Billings ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
High Altitude ◽  
Soil Development ◽  
Critical Zone ◽  
Parent Material ◽  
Rooting Depth ◽  
Organic C ◽  
C Storage ◽  
Topographic Positions ◽  
Alpine Environments

<p>Soils are a critical component of the Earth system in regulating many ecological processes that provide fundamental ecosystem services (Adhikari and Hartemink, 2016). Soil formation factors may be operating at faster timescales than is typically considered in recently deglaciated alpine environments, yielding important implications for critical zone services (e.g., water retention, the preservation of carbon (C) and nutrients, and chemical weathering fluxes). It remains unclear how variation in these properties are linked to soil development and soil organic C pools and fluxes, in part because sites varying in these characteristics also typically vary in vegetation and climate.</p><p>Here we leveraged the high-altitude alpine pastures of the Nivolet Critical Zone and Ecosystem Observatory, Gran Paradiso National Park (Italy) to examine biotic and abiotic dynamics and controlling factors of organic C and weathering under different topographic positions and geologic substrates in a small localized mountainous region. Soil profiles were sampled across a range of parent materials deposited after the Last Glacial Maximum, including gneiss glacial till, carbonate and calcschist/gneiss colluvium, and gneiss/carbonate/calcschist alluvium across ridgetop, midslope and footslope topographic positions. Organic C, C stable isotopes, major and trace element content, particle size distribution, and pH reveal how parent material and landscape position govern soil C storage and development. Even under the cold climate, limited season with liquid water, young-age deglaciated context, soils have developed incipient spodic horizons and calcschist clasts appears completely weathered in place.</p><p>Alkali and alkaline earth elements exhibit chemical depletion throughout the profiles, whereas in some profiles phosphorus concentrations reflects nutrient uplift processes (i.e., accumulating at the top of the profile and depleted in mid-horizons) likely driven by “biotic” cycling. Phosphorus is relatively high in uppermost horizons at carbonate and glacial sites, but is quite low in gneiss, even though TOC is relatively high, suggesting that plants underlain by gneiss are able to generate organic compounds with lower P availability. Though rooting depth distributions exhibit linear declines with depth, contrary the typically observed exponential decay behavior, our data suggest that roots serve as important biotic weathering agents prompting rapid soil development. All profiles have high organic carbon content at the surface, but</p><p>are twice as high in the footslope Gneiss profile as in the midslope Glacier and Carbonate profiles and in the floodplain Alluvial profile.</p><p>These data, in conjunction with microbial analysis and geochemical variation, suggest that biota are key agents promoting the observed high degree of soil development in these high altitude ecosystems. We demonstrate how in the early stages of soil development abiotic and biotic factors influence soil weathering and C storage across different parent material and topography.</p><p> </p><p>Adhikari, K. and Hartemink, A. E.: Linking soils to ecosystem services – A global review, Geoderma, 262, 101–111, 2016</p>

What limits deep water uptake by deep-rooted crops?

2020 ◽  
Author(s):  
Camilla Rasmussen ◽  
Eva Rosenqvist ◽  
Fulai Liu ◽  
Dorte Bodin Dresbøll ◽  
Kristian Thorup-Kristensen ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Water Uptake ◽  
Deep Water ◽  
Large Scale ◽  
Root Zone ◽  
Root Length Density ◽  
Yield Losses ◽  
Deep Soil ◽  
Deep Roots ◽  
Water Limitations

<p>Minimizing water limitation during growth of agricultural crops is crucial to unlocking full yield potentials. Crop yield losses vary according to timing and severity of water limitations, but even short-term droughts can be a major cause of yield losses. While the potential influence of deep roots on water uptake has been highlighted numerous times, the actual contribution of deep roots to water uptake is yet to be revealed. The objective of this study is to get an understanding of what limits deep water uptake by deep-rooted crops under topsoil water limitations.</p><p>We found that deep-rooted crops experience water limitations despite access to water stored in the deep soil and we hypothesize that deep water uptake by deep-rooted crops is limited by 1) the hydraulic conductivity of the deeper part of the root zone, arising from limited root length density in combination with the hydraulic resistance of the roots or 2) by a hormonal response arising from the plant sensing dry conditions in the shallow soil leading to stomata closure, to conserve water. The two hypotheses can of course not be valid simultaneously, but both might be valid under certain conditions, at certain times or for certain species.</p><p>In a large-scale semi-field setup, we grow oil seed rape and by combining measures of root development, root hydraulic conductivity, transpiration, stomatal conductance, ABA concentrations and soil water content from a large scale semi-field setup with a mechanistic 3-D root-soil modelling approach (R-SWMS), we are able to us distinguish various scenarios and to evaluate what limits deep water uptake.</p>

Root length density and water uptake in cereals and grain legumes: how well are they correlated

1987 ◽  
Vol 38 (3) ◽  
pp. 513 ◽  
Author(s):  
AP Hamblin ◽  
D Tennant
Keyword(s):  
Water Uptake ◽  
Root Length ◽  
Root Zone ◽  
Root Length Density ◽  
Genotypic Variation ◽  
Root Water Uptake ◽  
Grain Legumes ◽  
Rooting Depth ◽  
Rates Of Change ◽  
Axial Resistance

Total root length per unit ground area (La) is often considered to be directly related to the amount and rate of water uptake. Experiments were conducted to compare the water use of spring wheat, barley, lupin (L. angustifolius) and field pea on four differing soil types in drought-stressed conditions. The La values of cereals were consistently five to ten times as large as those of grain legumes, whereas the aboveground biomass was sim~iar and never greater than twice that of the grain legumes. Growing-season water loss (WL) from the soil profile was very similar for wheat and lupins, despite this big difference in root length. Soil evaporation may have been greater under lupins, but when crop water uptake was compared for the period when leaf area was greatest, rates of change in soil water content within the root zone were still similar and were not well correlated with La. Specific root water uptake (Ur) was consistently greater for lupin than wheat. Maximum rooting depth was better correlated with WL than was La in all cases. Higher Ur values in lupin and pea may be related to their large and abundant metaxylem vessels, which give much lower axial resistance than in cereals. These results provide strong evidence for genotypic variation in root morphology, density and root extension between dicotyledenous and monocotyledenous species. They also indicate that La is not necessarily the root morphological characteristic most responsible for efficiency of water uptake in drought-stressed environments.

scholarly journals Variation in the access to deep soil water pools explains tree-to-tree differences in drought-triggered dieback of Mediterranean oaks

2020 ◽  
Vol 40 (5) ◽  
pp. 591-604 ◽  
Author(s):  
Francesco Ripullone ◽  
J Julio Camarero ◽  
Michele Colangelo ◽  
Jordi Voltas
Keyword(s):  
Soil Water ◽  
Isotope Composition ◽  
Tree Height ◽  
Tree Size ◽  
Rooting Depth ◽  
Severe Drought ◽  
Deep Soil ◽  
Mediterranean Oaks ◽  
Water Values ◽  
Alternative Processes

Abstract Individual differences in the access to deep soil water pools may explain the differential damage among coexisting, conspecific trees as a consequence of drought-induced dieback. We addressed this issue by comparing the responses to a severe drought of three Mediterranean oak species with different drought tolerance, Quercus pubescens L. and Quercus frainetto Ten., mainly thriving at xeric and mesic sites, respectively, and Quercus cerris L., which dominates at intermediate sites. For each species, we compared coexisting declining (D) and non-declining (ND) trees. The stable isotope composition (δ2H, δ18O) of xylem and soil water was used to infer a differential use of soil water sources. We also measured tree size and radial growth to quantify the long-term divergence of wood production between D and ND trees and non-structural carbohydrates (NSCs) in sapwood to evaluate if D trees presented lower NSC values. The ND trees had access to deeper soil water than D trees except in Q. frainetto, as indicated by significantly more depleted xylem water values. However, a strong δ2H offset between soil and xylem water isotopes observed in peak summer could suggest that both tree types were not physiologically active under extreme drought conditions. Alternative processes causing deuterium fractionation, however, could not be ruled out. Tree height and recent (last 15–25 years) growth rates in all species studied were lower in D than in ND trees by 22 and 44%, respectively. Lastly, there was not a consistent pattern of NSC sapwood concentration; in Q. pubescens, it was higher in ND trees while in Q. frainetto, the D trees were the ones exhibiting the higher NSC concentration. We conclude that the vulnerability to drought among conspecific Mediterranean oaks depends on the differential access to deep soil water pools, which may be related to differences in rooting depth, tree size and growth rate.

scholarly journals Paleosols can promote root growth of recent vegetation – a case study from the sandy soil–sediment sequence Rakt, the Netherlands

SOIL ◽  
2016 ◽  
Vol 2 (4) ◽  
pp. 537-549 ◽  
Author(s):  
Martina I. Gocke ◽  
Fabian Kessler ◽  
Jan M. van Mourik ◽  
Boris Jansen ◽  
Guido L. B. Wiesenberg
Keyword(s):  
Three Dimensional ◽  
Soil Formation ◽  
Late Glacial ◽  
Growth Conditions ◽  
Parent Material ◽  
Rooting Depth ◽  
Deep Roots ◽  
Nutrient Contents ◽  
Soil Parent Material ◽  
Oak Trees

Abstract. Soil studies commonly comprise the uppermost meter for tracing, e.g., soil development. However, the maximum rooting depth of various plants significantly exceeds this depth. We hypothesized that deeper parts of the soil, soil parent material and especially paleosols provide beneficial conditions in terms of, e.g., nutrient contents, thus supporting their utilization and exploitation by deep roots. We aimed to decipher the different phases of soil formation in Dutch drift sands and cover sands. The study site is located at Bedafse Bergen (southeastern Netherlands) in a 200-year-old oak stand. A recent Podzol developed on drift sand covering a Plaggic Anthrosol that was piled up on a relict Podzol on Late Glacial eolian cover sand. Root-free soil and sediment samples, collected in 10–15 cm depth increments, were subjected to a multi-proxy physical and geochemical approach. The Plaggic Anthrosol revealed low bulk density and high phosphorous and organic carbon contents, whereas the relict Podzol was characterized by high iron and aluminum contents. Frequencies of fine (diameter  ≤  2 mm) and medium roots (2–5 mm) were determined on horizontal levels and the profile wall for a detailed pseudo-three-dimensional insight. On horizontal levels, living roots were most abundant in the uppermost part of the relict Podzol with ca. 4450 and 220 m−2, significantly exceeding topsoil root abundances. Roots of oak trees thus benefited from the favorable growth conditions in the nutrient-rich Plaggic Anthrosol, whereas increased compactness and high aluminum contents of the relict Podzol caused a strong decrease of roots. The approach demonstrated the benefit of comprehensive root investigation to support interpretation of soil profiles, as fine roots can be significantly underestimated when quantified at the profile wall. The possible rooting of soil parent material and paleosols long after their burial confirmed recent studies on the potential influence of rooting to overprint sediment–(paleo)soil sequences of various ages, sedimentary and climatic settings. Potential consequences of deep rooting for terrestrial deep carbon stocks, located to a relevant part in paleosols, remain largely unknown and require further investigation.

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