Impact of soil texture and water availability on the hydraulic control of plant and grape-berry development

Aims

All components of the soil-plant-atmosphere (s-p-a) continuum are known to control berry quality in grapevine (Vitis vinifera L.) via ecophysiological interactions between water uptake by roots and water loss by leaves. The scope of the present work was to explore how the main hydraulic components of grapevine influence fruit quality through changes in liquid- and gas-phase hydraulic conductance.

Methods

To reach our objectives, determinations of shoot growth, berry size and sugar content, leaf gas exchange, predawn leaf water potential (as a proxy of soil water potential), midday stem water potential and leaf water potential were performed in conjunction with anatomical measurements of shoot xylem. All measurements were conducted in two different cultivars (Cabernet franc and Merlot) and on three different soil types (clayey, gravelly, and sandy).

Results

Shoot xylem morphometric characteristics and whole-plant hydraulic conductance were influenced by cultivar and soil type. Differences in leaf gas exchange parameters and water potentials were determined by soil type significantly more than by cultivar. Between the two extremes (gravelly soil imposing drought conditions and sandy soil with easily accessible water) the clayey soil expressed an intermediate plant water consumption and highest sugar accumulation in berry.

Conclusions

Hydraulic and non hydraulic limitations to vine/berry interactions supported the conclusion that water availability in the soil overrides differences due to cultivar in determining the productive potential of the vineyard. Non hydraulic stomatal control was expected to be an important component on plants grown on the clayey soil, which experienced a moderate water stress. Possible links between hydraulic traits and berry development and quality are discussed.     

Fine root dynamics in Slovenian beech forests in relation to soil temperature and water availability

Key message

Fine root ingrowth and mortality of European beech are related to evapotranspiration, cumulative forest floor precipitation, soil temperature and water content, which are affected by forest management and gap creation.

Abstract

The ingrowth and mortality of European beech (Fagus sylvatica L.) fine roots (diameters <2 mm) were studied in relation to environmental variables describing temperature and water availability at four sites, covering a range in environmental conditions likely to be encountered in Slovenian beech forests. Minirhizotron images were used to determine fine root dynamics in a stand and gap in each of the sites for 12 periods during the 2007–2009 growing seasons. The environmental variables included air and soil temperatures, precipitation, forest floor precipitation, evapotranspiration and soil water contents. For data analysis, the daily mean values for each period for all variables were used. Fine root ingrowth and mortality were higher in the managed stand and gap compared to the old-growth stand and gap, but only significantly correlated with each other in the case of the managed stand. Forest floor precipitation and soil temperature were significant in explaining fine root ingrowth, whereas maximal evapotranspiration, soil temperature and soil water content were more important for fine root mortality. However, the correlations were weak and inconsistent among the four sites. By including site as predictor as well as environmental variables, R ² values of 0.49 and 0.55 for ingrowth and mortality, respectively, were achieved. Despite this, the relationships between the fine root dynamics and selected environmental factors appeared relatively weak and complex, especially for fine root ingrowth and might be partially related also to differences in successional stages of the forests under study.

     

Nitrogen uptake in relation to water availability in wheat

Nitrogen uptake and distribution in wheat (Triticum aestivum L.) are dependent on environmental conditions and in particular on the water regime. Under Mediterranean conditions, where high water stress at the end of the crop cycle is frequent, nitrogen uptake can be reduced, affecting yield and quality of the grain. To disclose these relations a field experiment was carried out in Central Portugal. Wheat was grown on a clay soil (Vertisol) at three water treatments: rainfed (WO), with 80 mm of irrigation (W1) and with 50 mm and 70 mm irrigations (W2). All treatments received 50 kg ha^–1 of N prior to sowing and were top-dressed with 140 kg ha^–1 of N, splitted in two applications, Kjeldahl N was determined in green leaves (GL), yellow leaves (YL), stems (ST), chaff (CH) and grain (GR). N uptake after anthesis was 40% of the total in W2, but was not noticeable in the other two treatments. N concentrations in the total above-ground plant dry matter, and in both YL and ST were not very different according to treatment, but water availability increased grain-N concentration. It seems, therefore, that grain protein concentration and N uptake can be substantially increased by late irrigations.     

Distribution and population dynamics of Collembola in relation to soil moisture

The significance of variations in soil moisture for the distribution and abundance of the four collembolan species Tomocerus minor, Orchesella cincta. Lepidocyrtus lignorum and Entomnbrya nivalis has been studied in a pine forest. During a relatively dry summer, the distribution and abundance of these species were examined on two sites with an initially different soil water content and depth of the titter/humus layer. The distribution of the species investigated could be described with the negative binomial distribution. During the sampling period. Lloyd's "index of patchiness", / for T. minor and E. nivalis was subject to changes. For T. minor this was probably related to soil water content.
The densities of T. minor and O. cincta were higher in the wet site than in the drier site. At the beginning and at the end of the sampling period the drought tolerant E. nivalis reached equal densities in both sites. The density fluctuations of the four species appeared to be totally different during the sampling period: the drought sensitive species T. minor decreased strongly, L. lignorum remained constant and the drought tolerant species O. cincta and E. nivalis increased strongly. These latter two species were able to survive the dry periods and to attain high densities by reproduction. The results agree with laboratory data on distribution and survival in relation to humidity.     

Growth of crop roots in relation to soil moisture extraction

Growth of the roots of sugar beet, potato and barley in the field was observed through glass panels and related to changes in soil moisture measured by a neutron probe during 1969–71. The depth of observed root growth was generally related to, but 10–15 cm deeper than, the maximum depth of soil-moisture extraction. On average of three years, sugar beet, potato and barley used water from the top 23, 33 and 45 cm soil respectively by the beginning of June, and from the top 70, 68 and > 100 cm soil by the end of June. Maximum soil drying in each horizon gave an in situ measure of available water capacity, and showed that sugar beet and barley eventually extracted similar amounts of water from each horizon, but potatoes extracted less, especially from below 60 cm. Between 30 and 100 cm deep, the in situ available water capacity (per 10 cm soil) progressively decreased from 16 to 10, 15 to 5 and 16 to 8 mm under sugar beet, potato and barley respectively. The calculated soil-moisture deficit (potential evapotranspiration minus rainfall) and measured soil moisture deficit were not related early in the growing period before the crops established much leaf cover.     

Factors of plant nutrient availability relevant to soil testing

Summary In most arable soils the nitrate availability depends mainly on the quantity of nitrate present in the rooting zone at the beginning of the growing season. Easily mineralizable organic N and the release of non-exchangeable NH₄ from clay minerals may in addition control the nitrogen availability during a season. In flooded soils, ammonium is the major form of nitrogen absorbed by plants. Ammonium dynamics in these soils is similar to that of potassium. The availability of both is controlled mainly by the intensity and buffering power for ammonium or potassium, respectively. Basically, intensity of the supply and buffering power for phosphate are the main factors determining the phosphate availability. The determination of the phosphate buffer power, especially in the root zone, however, remains to be difficult. Soil test methods should take into consideration the major factors and processes relevant to the availability of a particular plant nutrient.     

Long-term functional plasticity in plant hydraulic architecture in response to supplemental moisture

Background and Aims

Plasticity in structural and functional traits related to water balance may determine plant performance and survival in ecosystems characterized by water limitation or high levels of rainfall variability, particularly in perennial herbaceous species with long generation cycles. This paper addresses whether and the extent to which several such seasonal to long-term traits respond to changes in moisture availability.

Methods

Using a novel approach that integrates ecology, physiology and anatomy, a comparison was made of lifetime functional traits in the root xylem of a long-lived perennial herb (Potentilla diversifolia, Rosaceae) growing in dry habitats with those of nearby individuals growing where soil moisture had been supplemented for 14 years. Traditional parameters such as specific leaf area (SLA) and above-ground growth were also assessed.

Key Results

Individuals from the site receiving supplemental moisture consistently showed significant responses in all considered traits related to water balance: SLA was greater by 24 %; roots developed 19 % less starch storing tissue, an indicator for drought-stress tolerance; and vessel size distributions shifted towards wider elements that collectively conducted water 54 % more efficiently – but only during the years for which moisture was supplemented. In contrast, above-ground growth parameters showed insignificant or inconsistent responses.

Conclusions

The phenotypic changes documented represent consistent, dynamic responses to increased moisture availability that should increase plant competitive ability. The functional plasticity of xylem anatomy quantified in this study constitutes a mechanistic basis for anticipating the differential success of plant species in response to climate variability and change, particularly where water limitation occurs.     

The relationship between soil water storage capacity and plant species diversity in high alpine vegetation

Background: In those alpine regions where growing season precipitation is decreasing due to climate change, the capacity of soils to retain water may become an important factor for the persistence of plant species. However, the importance of soil water storage capacity (WSC) for plant species diversity has not been studied so far.

Aims: We aim to evaluate the relevance of WSC for species diversity of alpine plant communities in relation to temperature and length of growing season.

Methods: Species diversity was determined in 150 plots from a broad range of alpine vegetation types in the calcareous western part of the central Swiss Alps. WSC of soil cores sampled in every plot was determined, as well as rooting zone temperature and snowmelt date. Linear mixed models were used to assess the relationship between environmental data and species diversity.

Results: Species diversity was most strongly and positively related to WSC, followed by mean daily minimum temperature (T_min) of the growing season. Species diversity was significantly related to date of snowmelt only in sites with high WSC and/or T_min.

Conclusions: WSC represents an integrative measure for habitat quality and accounts for differences in species diversity within the study region. In order to understand and predict responses of plant species to climate change in high mountain regions, it may be crucial to also take changes in plant water supply into account.     

Interspecific variation in sapling mortality in relation to growth and soil moisture

To examine the causes of landscape variation in forest community composition, we have quantified sapling mortality as a function of growth and soil moisture for seven dominant species in transition oak-northern hardwood forests of the northeastern USA. We located saplings in sites that encompassed a wide range of variation in soil moisture and light availability. In mesic conditions, the probability of mortality decays rapidly with increasing growth among shade tolerant species and more gradually among shade intolerant species: the rank order of survivorship at low growth rates is Tsuga canadensis > Fagus grandifolia > Acer saccharum > Fraxinus americana > Acer rubrum > Quercus rubra > Pinus strobus . The relationship between probability of mortality and growth does not vary with soil moisture among species insensitive to drought: Tsuga canadensis , Quercus rubra, and Pinus strobus . However, probability of mortality increases substantially with decreasing soil water availability for the other four species. Acer saccharum and Fagus grandifolia have high mortality rates under xeric conditions even when their growth is not suppressed. Acer rubrum and Fraxinus americana exhibited a steady but more gradual increase in the probability of mortality with decreasing soil moisture. Among the five deciduous hardwood species we examined there is a weak inverse relationship between the ability to survive growth suppression, a measure of shade tolerance, and the ability to survive in xeric conditions, a measure of drought tolerance. Tsuga canadensis , however, is tolerant of growth suppression and exhibits high survivorship in xeric conditions, while Pinus strobus is intolerant of growth suppression but insensitive to soil moisture. Species differences in water-dependent mortality are consistent with the species distributions across landscape gradients of soil water availability.     

Root distribution in relation to soil nitrogen availability in field-grown tomatoes

Tomato root growth and distribution were related to inorganic nitrogen (N) availability and turnover to determine 1) if roots were located in soil zones where N supply was highest, and 2) whether roots effectively depleted soil N so that losses of inorganic N were minimized. Tomatoes were direct-seeded in an unfertilized field in Central California. A trench profile/monolith sampling method was used. Concentrations of nitrate (NO₃ ^-) exceeded those of ammonium (NH₄ ⁺) several fold, and differences were greater at the soil surface (0–15 cm) than at lower depths (45–60 cm or 90–120 cm). Ammonium and NO₃ ^- levels peaked in April before planting, as did mineralizable N and nitrification potential. Soon afterwards, NO₃ ^- concentrations decreased, especially in the lower part of the profile, most likely as a result of leaching after application of irrigation water. Nitrogen pool sizes and rates of microbial processes declined gradually through the summer.Tomato plants utilized only a small percentage of the inorganic N available in the large volume of soil explored by their deep root systems; maximum daily uptake was approximately 3% of the soil pool. Root distribution, except for the zone around the taproot, was uniformly sparse (ca. 0.15 mg dry wt g^-1 soil or 0.5 cm g^-1 soil) throughout the soil profile regardless of depth, distance from the plant stem, or distance from the irrigation furrow. It bore no relation to N availability. Poor root development, especially in the N-rich top layer of soil, could explain low fertilizer N use by tomatoes.     

Growth phenology and water potential patterns of Periploca angustifolia in relation to water availability

Periploca angustifoliaLabill., is a multipurpose shrub also used to rehabilitate drylands. It is essential to understand its phenological patterns under arid conditions. In order to understand how plants manage extreme drought, this study investigates the relationship between phenological traits of P. angustifolia Labill., water potential and climatic conditions. During two successive growing seasons (Sep 2009–Augst 2011) phenological patterns, soil water content and water potentials were measured monthly for plants of Periploca angustifoliaLabill growing under rain-fed conditions (Annual rainfall = 168 mm) at the pastoretum of the Arid Regions Institute in southern Tunisia. The Ψmd decreased progressively and concomitantly with increasing seasonal drought, reaching the lowest values in late summer (down to –3 MPa). Water potentials of P. angustifoliaLabill were affected by spatial and temporal variations in soil water content. The increased diurnal amplitude values (∆ψ > −1.3 MPa) explained the especially high biological activity of this species during the dry season. Our results clearly demonstrate that P. angustifolia Labill is a drought-tolerant species reaching low water potentials during the driest months of summer. These characteristics make this shrub as promising for rehabilitating degraded arid ecosystems.     

土壤水分时空变异及其与环境因子的关系

土壤水分的时空变异是指在一定的景观内,不同时间、地点和土层的土壤水分特征存在明显的差异性和多样性。土壤水分时空变异是由多重尺度上的土地利用（植被）、气象（降雨）、地形、土壤、人为活动等诸因子综合作用的结果,但就其某一具体地区而言存在着重点尺度和主控因子,土壤水分时空变异的重点尺度与主控因子的时空关系因时间、空间和尺度而异。本文综述了土壤水分（尤其是黄土高原地区）的时空变异与其环境因子时空关系的研究进展,并提出了广眨开展多重时空尺度上土壤水分的时空变异与其诸因素的时空关系,研究土壤水分时空变异性的尺度转换规律,确定重点尺度及其相应的主控因子。     

The role of adaptive strategies in plant naturalization

Determining the factors associated with the naturalization of alien species is a central theme in ecology. Here, we tested the usefulness of a metric for quantifying Grime's seminal concept of adaptive strategies – competitors, stress‐tolerators and ruderals (CSR) – to explain plant naturalizations worldwide. Using a global dataset of 3004 vascular plant species, and accounting for phylogenetic relatedness and species’ native biomes, we assessed the associations between calculated C‐, S‐ and R‐scores and naturalization success for species exhibiting different life forms. Across different plant life forms, C‐scores were positively and S‐scores negatively associated with both the probability of naturalization and the number of regions where the species has naturalized. R‐scores had positive effects on the probability of naturalization. These effects of the scores were, however, weak to absent for tree species. Our findings demonstrate the utility of CSR‐score calculation to broadly represent, and potentially explain, the naturalization success of plant species.     

Stem radial growth and water storage responses to heat and drought vary between conifers with differing hydraulic strategies

We investigated stem radial growth and water storage dynamics of 2 conifer species differing in hydraulic carbon strategies, Juniperus monosperma and Pinus edulis, under conditions of ambient, drought (～45% reduction in precipitation), heat (～4.8 °C temperature increase), and the combination of drought + heat, in 2013 and 2014. Juniper maintained low growth across all treatments. Overall, the relatively isohydric piñon pine showed significantly greater growth and water storage recharge than the relatively anisohydric juniper across all treatments in the average climate year (2014) but no differences in the regionally dry year (2013). Piñon pine ceased growth at a constant predawn water potential across all treatments and at a less negative water potential threshold than juniper. Heat has a greater negative impact on piñon pines' growth and water storage than drought, whereas juniper was, in contrast, unaffected by heat but strongly impacted by drought. The whole‐plant hydraulic carbon strategies, in this case captured using the isohydric/anisohydric concept, translate into alternative growth and water storage strategies under drought and heat conditions.     

土壤有机质对土壤水分保持及其有效性的控制作用

如何基于常规测定因子评估森林在土壤水分保持方面的生态效益, 并建立森林固碳效益与水文效益的联系等科学问题, 在综合评估森林生态效益方面有着重要意义。该文以南亚热带地区的3种不同演替阶段的森林生态系统(人工恢复的马尾松针叶林(Pinus massoniana coniferous forest, PF)、马尾松针阔叶混交林(mixed Pinus massoniana-broad-leaved forest, PBF)和季风常绿阔叶林(monsoon evergreen broad-leaved forest, MBF))为研究对象, 通过分析其土壤有机质及土壤水分状况在林内及林型间的分布格局差异, 探讨土壤有机质对土壤水分保持的控制作用。结果表明: 由PF至地带性顶级群落MBF的3种林分虽然相距很近且有关环境因子一致, 但0-30 cm土层的土壤含水量差异显著, MBF的最高, PBF其次; 3种林型林内土壤水分分布格局迥异, MBF的土壤水分随土层加深而递减的趋势明显, PBF土壤各层水分较为均一, PF则土壤表层水分含量较低, 与土壤有机质的状况一致。土壤水分特征曲线显示, 0-40 cm土层在相同基质吸力条件下的土壤水分含量: MBF > PBF > PF, MBF的保水性最好。进一步分析发现, 土壤孔隙度对土壤含水量的影响最大, 饱和含水量、土壤有机质次之, 同时, 考虑到土壤孔隙度和土壤饱和含水量对土壤有机质的高度依赖性, 我们认为土壤有机质控制着土壤含水量及其有效性( p= 0.014)。作为常规测定指标的土壤有机质, 不仅是森林固碳效益的关键指标, 而且可用来量度土壤水分保持及其有效性, 可以作为评价森林生态系统服务功能的一个综合指标。     

The interrelationship of meteorological factors,soil moisture and plant growth

A thorough review of literature pertaining to the role of soil moisture in the interrelationships between meteorological factors and plant growth has been presented. In arid and semi-arid areas crop yields are closely related to the supply of soil moisture during the growing season. Direct measurements of soil moisture are laborious, costly or sometimes unpracticable. Unless sufficiently replicated they do not represent the natural variations of moisture in the soil. Moisture budgets computed from standard climatological data to some extant satisfy the need for a time-space-integrating technique. Most budget methods make use of potential evapotranspiration as the maximum loss of water from soil and vegetation when water supply is non-limiting. Under dry-land conditions the rate of PE must be modulated to account for soil dryness, plant root system, soil characteristics and atmospheric conditions. Soil moisture estimates so obtained may be used to interpret variations in plant growth and crop yields, for crop zonation purposes,for agroclimatic classifications, as a basis for crop forecasts and so forth.

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Zusammenfassung In einer ausführlichen Übersicht wird der derzeitige Stand der Arbeiten über die Bedeutung der Bodenfeuchtigkeit in den Wechselbeziehungen zwischen meteorologischen Faktoren und Pflanzenwachstum berichtet. In ariden und semi-ariden Gebieten werden die Ernteerträge weitgehend bestimmt durch den Bodenfeuchtevorrat während der Wachstumszeit. Direkte Messungen der Bodenfeuchtigkeit sind aufwendig und manchmal undurchführbar. Erst viele Wiederholungen ergeben ein getreues Bild der natürlichen Streuungen der Feuchteverteilung im Bodenprofil.Wasserbilanzen, die anhand von Klimadaten berechnet werden, genügen ungefähr der Forderung nach einer Raum-Zeit integrierenden Technik. Die meisten Wasserbilanzmethoden verwenden die potentielle Evapotranspiration als Ausgangswert für den höchst möglichen Wasserverlust von Boden und Vegetation bei ungehindertem Wassernachschub. Im Freiland ohne zusätzliche Beregnung muss zur Abschätzung des tatsächlichen Wasserverlustea die potentielle Evapotranspiration um einen Betrag vermindert werden,der abhängig ist von der Austrocknung des Bodens, Wurzelsystem, Bodeneigenschaften und atmospherischen Bedingungen. Diese Bodenfeuchte-Schätzwerte können zur Erklärung von Schwankungen im Pflanzenwachstum und der Enteerträge, für die Abgrenzung von Vegetationszonen, für agrarklimatologische Klassifikationen, als Basis für Ernteertragsvorhersagen und für ähnliche Planungen gebraucht werden.

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Resume Le présent article passe en revue les différentes méthodes en usage pour calculer, estimer ou mesurer les pertes en eau du sol. En effet,dans tous les climats arides ou semi-arides, l'évapotranspiration est déterminante pour la production agricole. On peut ainsi établir les fluctuations du bilan hydrique du sol pour des laps de temps plus ou moins courts, en tenant compte du fait que l'évapotranspiration n'est pas seulement fonction des éléments météorologiques,mais aussi de la réserve en eat du sol: la première diminuant avec l'apauvrissement de la seconde.Le bilan hydrique du sol connu et calculé pour des périodes successives,il est possible d'établir de. précisions de récoltes. Celles-ci doivent être rectifiées périodiquement au fur et à mesure de l'avancement de la saison. Cet article est accompagné d'une très riche liste de publications traitant soit de la détermination de l'évapotranspiration,soit du calcul du bilan hydrique, soit enfin de son utilisation dans la précision des récoltes.

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Contribution No. 428 of the Plant Research Institute, Research Branch, Canada Department of Agriculture, Ottawa. Presented of the Symposium on Water and Climate, Saskatoon, Saskatchewan, 13 November 1964.