Water Uptake by Plant Roots — a Multi-Scale Approach

Mendel, Markus; Hergarten, Stefan; Neugebauer, Horst J.

doi:10.1007/3-540-45256-7_13

Cited by 6 publications

(7 citation statements)

References 26 publications

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“…This indicates that liquid phases are usually isotopically more enriched (Mark, 2011) than the vapour phases. However, one of the ways by which soil loses water is plant root uptake, water uptake and transport through the root system have been described as passive processes (Mendel et al, 2003). Therefore, fractionation of stable isotopes of water does not occur during root uptake as evaporation of soil waters takes place before they have been taken up by plants (Liu et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Estimation of soil water evaporative loss after tillage operation using the stable isotope technique

Busari¹,

Salako²,

Tuniz³

et al. 2013

International Agrophysics

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A b s t r a c t. Application of stable isotopes in soil studies has improved quantitative evaluation of evaporation and other hydrological processes in soil. This study was carried out to determine the effect of tillage on evaporative loss of water from the soil. Zero tillage and conventional tillage were compared. Suction tubes were installed for soil water collection at the depths 0.15, 0.50, and 1.0 m by pumping soil water with a peristaltic pump. Soil water evaporation was estimated using stable isotopes of water. The mean isotopic composition of the soil water at 0.15 m soil depth were -1.15‰ (d 18 O) and -0.75‰ (dD) and were highly enriched compared with the isotopic compositions of the site precipitation. Soil water stable isotopes (d 18 O and dD) were more enriched near the surface under zero tillage while they were less negative down the profile under zero tillage. This suggests an occurrence of more evaporation and infiltration under conventional then zero tillage, respectively, because evaporative fractionation contributes to escape of lighter isotopes from liquid into the vapour phase leading to enrichment in heavy isotopes in the liquid phase. The annual evaporation estimated using the vapour diffusion equation ranges from 46-70 and 54-84 mm year -1 under zero and conventional tillage, respectively, indicating more evaporation under conventional tillage compared with zero tillage. Therefore, to reduce soil water loss, adoption of conservation tillage practices such as zero tillage is encouraged.K e y w o r d s: evaporative loss, tillage, isotopic fractionation, isotope technique INTRODUCTIONTillage is mechanical manipulation of the soil for the purpose of crop production and it affects significantly soil characteristics such as soil water conservation, soil temperature, infiltration and evapotranspiration processes. As tillage is known to cause soil surface disruption, fractionation of stable isotopes following soil tillage has been documented (Angela et al., 2009). Although tilled plots may have very high initial infiltration rate values, these rates rapidly decline with time (Guzha, 2004) probably due to intense alteration of the top centimetres of the soil (Josa et al., 2010) and rapid structural deterioration caused by slaking and dispersion. However, due to the effect of increased soil organic matter (Lipiec et al., 2006) and soil surface protection, high infiltration under zero tilled (ZT) plots have been documented (Shukla et al., 2003). According to Gupta et al. (2004) less intense tillage keeps the crop residue at the soil surface, thereby increasing the activity of surface-feeding earthworms, leaving the root channels undisturbed, leading to the presence of numerous surface-connected macro-pores and inter-pedal, hence higher infiltration. It has been reported that lower soil temperature due to higher water content in the topsoil and more plant residues on the soil surface under ZT usually result in reduced evaporation, whereas the opening of topsoil enhances evaporation from the tille...

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Section: Introductionmentioning

confidence: 99%

Estimation of soil water evaporative loss after tillage operation using the stable isotope technique

Busari¹,

Salako²,

Tuniz³

et al. 2013

International Agrophysics

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“…Through its utilization of soil water, vegetation has an important impact on the shallow soil water system [23], and the soileroote stem water pathway is a major component of subsurface hydrological systems [28]. Moreover, the depth and distribution of plant roots define the area from which plants can potentially absorb soil water [42].…”

Section: Introductionmentioning

confidence: 99%

“…Evaporation of water from the soil usually takes place prior to the uptake of water by vegetation [9,36]. Meanwhile, water uptake and transport through the root system are passive processes [28], and if osmotic effects are neglected, plants do not fractionate water during the uptake and transport process except near the leaf [3,4]. Hence, the stable isotopic composition of plant water (e.g.…”

Section: Introductionmentioning

confidence: 99%

Analyzing relationships among water uptake patterns, rootlet biomass distribution and soil water content profile in a subalpine shrubland using water isotopes

Liu

Duffy

et al. 2011

European Journal of Soil Biology

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“…depend on the considered scales. On the comparatively small scales, explicit modelling of the dynamical processes and the coupling between different scales is possible (Mendel et al 2002). On larger scales, the numerical solution of the underlying differential equations is only feasible using a coarser resolution.…”

Section: Introductionmentioning

confidence: 99%

Multi-Scale Processes and the Reconstruction of Palaeoclimate

Gebhardt

Kühl

Hense

et al.

Lecture Notes in Earth Sciences

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Abstract. In this section, we focus on multi-scale problems encountered when reconstructing palaeoclimate on the basis of terrestrial botanical proxy data (pollen and macro remains). Climate and the taxonomical composition of the vegetation are affected and linked by complex geoprocesses acting on various spatial and temporal scales. We describe how the resolution of these data -both in space and time -limits the scale of features which can be reconstructed. We then present a Bayesian statistical transfer function relating vegetation and climate which is based on a Boolean approach ("taxon existent"-"taxon nonexistent"). This transfer function allows for an effective avoidance of "no modern analogue"-situations and intents to reduce the influence of sub-scale processes (e. g. local effects) and of non-climatic factors on the reconstruction. We present two types of transfer functions: a reconstruction model suitable for reconstructions of local palaeoclimate and a backward model which can be used to reconstruct spatially coherent climatological fields. The reconstruction model is given by probability density functions for the climate conditional on the existence of certain taxa. The backward model is deduced from the reconstruction model in a straightforward way using the Bayes theorem. For the spatially coherent reconstruction, the backward model is combined with a dynamical constraint in order to stabilise the reconstruction which is normally based on a relatively sparse network of palaeo-observations. We use a singular value decomposition of the dynamics to restrict the reconstruction to the dominant and resolvable scales.

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Water Uptake by Plant Roots — a Multi-Scale Approach

Cited by 6 publications

References 26 publications

Estimation of soil water evaporative loss after tillage operation using the stable isotope technique

Estimation of soil water evaporative loss after tillage operation using the stable isotope technique

Analyzing relationships among water uptake patterns, rootlet biomass distribution and soil water content profile in a subalpine shrubland using water isotopes

Multi-Scale Processes and the Reconstruction of Palaeoclimate

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