Capillary Movement Of Water Research Articles

Influence of Long-Term Mulched Drip Irrigation on Upward Capillary Water Movement Characteristics in the Saline–Sodic Region of Northwest China

Capillary water, serving as a crucial intermediary between groundwater and crop root layer moisture, is important for both soil retention and crop utilization. To investigate the effect of mulched drip irrigation (MDI) on upward capillary water in cotton fields with different application years (0, 10, 14, 18, 20, and 24 years) in the saline–sodic region of Northwest China, an indoor soil column test (one-dimensional capillary water rise experiment) was conducted. The results showed that the wetting front transport law, capillary water recharge, and wetting front transport rate over time exhibited an increasing trend in the early stages of MDI application (10 and 14 years), peaking at 18 years of application, followed by a decreasing trend. The relationship between the capillary water recharge and rising height was fitted based on the Green–Ampt model, and their slopes reveal that 14 and 18 years of MDI application required the largest amount of water per unit distance, indicating an excellent water-holding capacity beneficial for plant growth. Conversely, 0 years required the smallest amount of water per unit distance. Based on the movement characteristics of upper capillary water, we confirmed that the MDI application years (0–18 years) improves soil infiltration capacity, while the long-term application years (18–24 years) reduces groundwater replenishment to the soil. Furthermore, the HYDRUS-1D model was employed to simulate the capillary water rise process and soil moisture distribution under different MDl application years. The results showed an excellent consistency with the soil column experiments, confirming the accuracy of HYDRUS-1D in simulating the capillary water dynamics in saline–sodic areas. The results would provide suggestions to achieve the sustainable development of long-term drip-irrigated cotton fields.

Soil compaction reversed the effect of arbuscular mycorrhizal fungi on soil hydraulic properties

Arbuscular mycorrhizal fungi (AMF) typically provide a wide range of nutritional benefits to their host plants, and their role in plant water uptake, although still controversial, is often cited as one of the hallmarks of this symbiosis. Less attention has been dedicated to other effects relating to water dynamics that the presence of AMF in soils may have. Evidence that AMF can affect soil hydraulic properties is only beginning to emerge. In one of our recent experiments with dwarf tomato plants, we serendipitously found that the arbuscular mycorrhizal fungus (Rhizophagus irregularis ‘PH5’) can slightly but significantly reduce water holding capacity (WHC) of the substrate (a sand–zeolite–soil mixture). This was further investigated in a subsequent experiment, but there we found exactly the opposite effect as mycorrhizal substrate retained more water than did the non-mycorrhizal substrate. Because the same substrate was used and other conditions were mostly comparable in the two experiments, we explain the contrasting results by different substrate compaction, most likely caused by different pot shapes. It seems that in compacted substrates, AMF may have no effect upon or even decrease the substrates’ WHC. On the other hand, the AMF hyphae interweaving the pores of less compacted substrates may increase the capillary movement of water throughout such substrates and cause slightly more water to remain in the pores after the free water has drained. We believe that this phenomenon is worthy of mycorrhizologists’ attention and merits further investigation as to the role of AMF in soil hydraulic properties.

Super absorbent polymer (SAP) on water‐salt transport in saline alkali soil: Effects of dosage, height and thickness

AbstractSoil salinisation is a pervasive form of land degradation posing a significant threat to the global environment. Saline soil, covering roughly 10% of the total land area, represents a crucial reserve of land resources. The use of super absorbent polymer (SAP) impacts capillary water movement through the soil because of its exceptional water absorption and retention capabilities. SAP is expected to influence the intricate water‐salt migration processes and their redistribution within soil. This study employed soil column experiments to investigate the impacts of varying SAP dosages (A), heights (B) and thicknesses (C) on soil water and salt transport in the Tianjin Binhai New Area, China. The main findings showed that: (1) average capillary water rise rate decreased with SAP dosage increase. The groundwater recharge trend in time was like that of capillary water rise height; (2) SAP usage increased water and salt content on the application layer and reduced surface soil salt accumulation; (3) the best SAP combination for application was 1.1% SAP at 17–18 cm from the groundwater level. This study provides basic effective SAP application strategies for preventing soil salinisation.

Effects of Earthworm Cast Application on Water Evaporation and Storage in Loess Soil Column Experiments

Earthworm cast is a common bio-organic fertiliser, which can effectively improve soil fertility and structure. However, only a few studies have focused on the effect of earthworm cast on soil water movement. In this study, loess soil was used to determine the effects of earthworm cast application on soil evaporation. The effects on water storage capacity and capillary upward movement were also investigated. A laboratory-based soil column experiment using earthworm cast with different particle sizes (1–3 × 1–2 cm and 3–5 × 2–4 cm) and three application doses (5%, 7.5%, and 10%) was carried out. The daily evaporation and volume of capillary ascension were monitored. The addition of earthworm cast clearly affected the soil evaporation by changing soil water storage capacity and capillary water upward movement. Compared with control soil, the application of 5% small-particle cast reduced the soil cumulative evaporation by 5.13%, while the cumulative evaporation was higher in all large-particle cast treatments. The upward capillary water movement increased with increasing dose of earthworm cast, but decreased with increasing particle size. Overall, the addition of earthworm cast clearly enhanced the water storage capacity of the soil, with the small-particle cast having greater effects than the large-particle cast. We concluded that the application of 5% small-particle earthworm cast can enhance soil water retention and reduce soil evaporation.

Project design abacus for wall base ventilation drying systems to control dampness

ABSTRACTDampness is an important degradation issue especially in old buildings and monumental heritage, particularly a rising one as the result of capillary movement of water in the lower sections of walls and other ground-supported structures by capillary action. There are several methods to treat this kind of dampness among which is the wall base hygro-regulated ventilation system an interesting solution for high thick walls with considerable heterogeneity.A significant number of studies have been undertaken around this method which have been implemented and validated in several heritage buildings. Such achievement has led to the adoption of the HUMIVENT patent system which aims to increase evaporation through peripheral channels on the base of the ventilated walls. A pre-sizing design program was also created and was called HUMIVENT PREDIM.This study aims to develop a set of auxiliary abacus for pre-sizing wall base ventilation systems. This approach aims to provide fast and expeditious systems sizing in the design and rehabilitation project offices. It allows an easy awareness in the several parameters that influence the wet front and the preliminary ventilation system design. It is a very useful tool for designers allowing them to obtain pre-sizing without extensive knowledge of the program and the associated parameters and with quick understanding of the drying process optimization. For better awareness of the abacus’ potentiality and use, an application example is provided thereof. It is concluded that the abacus can straightforwardly be used for sensitivity studies and for the selection of the best solution in each case.

The influence of surfactant and organic matter content on wetting pattern of different non-water repellent soils

Non-ionic surfactants have been well researched as a tool to ameliorate water repellent conditions. However, few studies have evaluated the risks and benefits of non-ionic surfactant applications in wettable soil. The objective of this study was to evaluate the effects of a surfactant in modifying the wetting pattern in soils of different textures and organic matter contents. The experimental treatments consisted of (1) four different soil textures including sandy, sandy loam, sandy clay loam and silt loam, (2) four different organic matter contents (0.2, 0.7, 1.2 and 1.7% by weight), and (3) irrigation water treatments with or without surfactant (IrrigAid Gold). The experiment was carried out in Plexiglas boxes with one drip emitter under the soil surface. The results demonstrated the superiority of surfactant application on increasing water distribution in the soil profile for all soil textural classes. Silt loam texture had the highest side wetted area and wetting depth 45min after the initiation of irrigation. Upward capillary water movement and top wetted area significantly decreased in the surfactant treatment across all soil textures except in sandy soil. As organic matter content increased, top wetted area decreased. These findings clarified the potential ability of surfactant in increasing water infiltration in non-repellent soil in an in vitro system.

Surface water hydrology and geomorphic characterization of a playa lake system: Implications for monitoring the effects of climate change

Playa lakes are sensitive recorders of subtle climatic perturbations because these ephemeral water bodies respond to the flux of diffuse and channelized flow from their watersheds as well as from direct precipitation. The Black Rock Playa in northwestern Nevada is one of the largest playas in North America and is noted for its extreme flatness, varying less than one meter across a surface area of 310 km2. Geo-referenced Landsat imagery was used to map surface-area fluctuations of ephemeral lakes on the playa from 1972 to 2013 to provide baseline data on surface water hydrology of this system to compare to future hydrologic conditions caused by climate change. The area measurements were transformed into depth and volumetric estimates using results of detailed topographic global positioning system (GPS) surveys and correlated with available surface hydrological and meteorological monitoring data. Playa lakes reach their maximum size (<350 km2) in spring, fed by melting snows from high mountains on the periphery of the drainage basin, and usually desiccate by early- to mid-summer. The combination of a shallow groundwater table, sediment deposition, and hydro-aeolian planation probably are largely responsible for the flatness of the playa. When lakes do not form for a period of several years, the clay- and silt-rich playa surface transforms from one that is hard and durable into one that is soft and puffy, probably from upward capillary movement of water and resultant evaporation. Subsequent flooding restores the hard and durable surface. The near-global availability of Landsat imagery for the last 41 years should allow the documentation of baseline surface hydrologic characteristics for a large number of widely-distributed playa lake systems that can be used to assess the hydrologic effects of future climate changes.

Development of a small-plant bioassay to assess banana grown from tissue culture for consistent infection byFusarium oxysporumf. sp.cubense

Two reliable small-plant bioassays were developed using tissue-cultured banana, resulting in consistent symptom expression and infection by Fusarium oxysporum f. sp. cubense (Foc). One bioassay was based on providing a constant watertable within a closed pot and the second used free-draining pots. Culture medium for spore generation influenced infectivity of Foc. Inoculation of potted banana by drenching potting mix with a conidial suspension, consisting mostly of microconidia, few macroconidia and no chlamydospores, generated from one-quarter-strength potato dextrose agar + streptomycin sulfate, resulted in inconsistent infection. When a conidial suspension that consisted of all three spore types, microconidia, macroconidia and chlamydospores, prepared from spores generated on carnation leaf agar was used, all plants became infected, indicating that the spore type present in conidial suspensions may contribute to inconsistency of infection. Inconsistency of infection was not due to loss of virulence of the pathogen in culture. Millet grain precolonised by Foc as a source of inoculum resulted in consistent infection between replicate plants. Sorghum was not a suitable grain for preparation of inoculum as it was observed to discolour roots and has the potential to stunt root growth, possibly due to the release of phytotoxins. For the modified closed-pot system, a pasteurised potting mix consisting of equal parts of bedding sand, perlite and vermiculite plus 1 g/L Triabon slow release fertiliser was suitable for plant growth and promoted capillary movement of water through the potting mix profile. A suitable potting mix for the free-draining pot system was also developed.

Organic manure stimulates biological activity and barley growth in soil subject to secondary salinization

A pot experiment was performed to compare the impact of organic manure on soil enzymatic activity, respiration rate and the growth of two barley cultivars ( Hordeum vulgare L.) differing in their salt tolerance under a simulated salinized environment. A plastic pot with a hole (2 cm in diameter) in the center of bottom was filled with an anthropogenic (paddy) soil and placed in a porcelain container containing NaCl solution (3.0 g L −1) such that a secondary salinization process was simulated via upward capillary water movement along the soil profile. A treatment with neither organic manure nor simulated soil salinization was taken as a control (CK1). The organic manure was applied either inside or outside rhizobag made of nylon cloth (40 μm of pore size). The soil was treated with: 20 g kg −1 rice straw (RS), 20 g kg −1 pig manure (PM), or 10 g kg −1 rice straw plus 10 g kg −1 pig manure (RS+PM). No organic manure was added in an additional control treatment (CK2). The results indicated that the placement of organic manure both inside and outside rihzobags significantly increased the activity of urease, alkaline phosphatase and dehydrogenase, as well as respiration rate in both rhizosphere and bulk soils. Also, nutrient uptake by barley plants was enhanced in the treatments with organic manure amended either inside or outside rhizobags. The activity of these enzymes along with the respiration rate was higher in rhizosphere than in non-rhizosphere when organic manure was supplied inside rhizobags, while the opposite was found in the case of manure incorporated outside rhizobags. Among all the treatments, RS+PM treatment had most significant stimulating effects on enzymatic and microbial activity and shoot dry weight of barley, followed by PM and RS. Moreover, more significant stimulating effects on both enzyme activity and plant growth were achieved in the treatments with manure amended inside rhizobags than outside rhizobags. The results of the present study confirmed the view that incorporation of organic manure especially into soil–root zones is an effective low-input agro-technological approach to enhancing soil fertility and minimizing phytotoxicity induced by secondary salinization.

Physiological Response of Carambola Trees to Soil Water Depletion in Krome Soils

The effect of soil water depletion on plant water potential and leaf gas exchange of carambola (Averrhoa carambola L. cv. Arkin) in Krome very gravelly loam soil was studied in an orchard and in containers in the field and in a greenhouse. The rate of soil water depletion was determined by continuously monitoring soil water content with multi-sensor capacitance probes. Stem water potential and leaf gas exchange of carambola in containers were reduced when the soil water depletion level fell below 50% (where field capacity = 100%). Although there was a decrease in the rate of soil water depletion in the orchard as the soil dried, soil water depletion did not go below an average of 70%. This was presumably due to sufficient rainfall and capillary movement of water in the soil. Therefore, soil water content did not decline sufficiently to affect leaf gas exchange and leaf and stem water potential of orchard trees. A decline in soil water depletion below 40% resulted in a concomitant decline in stem water potential of the container trees in the field and greenhouse to below -1.0 MPa. Stomatal conductance, net CO2 assimilation, and transpiration declined significantly when stem water potential was below -1.0 MPa. The reduction of net CO2 assimilation and transpiration was proportional to the decline in stomatal conductance of container trees in the field and greenhouse. Thus, soil water depletion in Krome very gravelly loam soil must be less than 50% before water potential or leaf gas exchange of carambola is affected. Based on these results, irrigation scheduling should be based on physiological variables such as stem water potential and stomatal conductance or the amount rather than the rate of soil water depletion.

Alternate watering in soil vertical profile improved water use efficiency of maize ( Zea mays)

A new method of irrigation was designed and tested for its biomass production and water use efficiency (WUE) in pot-grown maize. Maize plants were grown in pots with their roots vertically separated into two parts. A 5 cm layer of stone chips (diameter 3–6 mm) was used to separate the upper and lower parts so that capillary movement of water between the two parts was prevented without restricting root penetration. Watering and soil drying could be applied independently on either part of the soil column. Results showed that when water consumption was reduced by 20% (moderate soil drying) and 40% (severe soil drying) through extending the watering intervals, the alternate watering (AW), or drying, on either part of the soil column largely maintained its biomass production under moderate soil drying. In addition, AW outperformed bottom watering (BW) or surface watering (SW) in biomass production when the same amount water was consumed. Root development, as both root length and dried mass, was significantly enhanced. Significant increases in WUE and root to shoot ratio were observed as a result of the AW treatment. Rate of photosynthesis of AW under moderate or severe soil drying was enhanced when compared to BW or SW under similar soil drying treatments. The results also showed that total nutrient uptake, the K and N, and shoot biomass production were enhanced by alternate drying and rewatering in two parts in the vertical soil profile. We conclude that controlled AW in the vertical soil profile is an effective and water-saving method and may have potential to be used in the field.

EFFECT OF PEATLAND DRAINAGE, HARVESTING, AND RESTORATION ON ATMOSPHERIC WATER AND CARBON EXCHANGE

There is a limited understanding of the hydrological and microclimatic processes from drained, harvested, or restored peatlands, and by extension the nature of the carbon balance is uncertain. However, understanding the symbiotic processes governing water and gas exchange is essential to the development of appropriate management plans for peatland restoration. In this paper, we highlight and contrast the suite of processes governing the atmospheric exchange of water and carbon on natural, harvested, and restored peatlands. Evapotranspiration from harvested sites is important throughout the spring and summer, and is not greatly different from the adjacent natural bog. On cutover peatlands, strong capillary water movement compensates for the lack of vascular plants, which on the natural bog become increasingly important as the capillary water movement within drying Sphagnum decreases. Methane emissions from cutover bogs are an order of magnitude lower than in natural sites, however, carbon dioxide (CO2) emissions are approximately three times greater. Peatland restoration enhances CO2 sequestration, although restoration (at least in the short term) does not restore the net carbon sink function to that in natural bogs. A conceptual model highlighting these changes in the atmospheric exchange of water and carbon from a natural bog through drainage, harvesting, abandonment, and restoration is presented. [Key words: peatlands, restoration, hydrology, climatology, evaporation, carbon dioxide, methane, harvested peatlands.]

Genesis and evolution of gypsum tumuli

Tumuli are hollow subcircular domes of the most superficial stratum of gypsum, principally found in outcrops of macrocrystalline gypsum. They vary from a few centimetres to several metres in diameter and reach maximum heights of a little more than 1 m. The relationships between the morphostatistical parameters that define these formations are: h = r/3 and e = r/9, where h is the elevation of the raised layer, e its thickness and r the mean radius. Their genesis has caused some controversy over the involvement of phenomena such as hydration of anhydrite, or tectonic processes capable of explaining this folding. This paper shows their genesis linked to the dissolution of macrocrystalline gypsum and reprecipitation of microcrystalline gypsum within the same gypsiferous layer. It has been calculated that to reach the theoretical saturation within the few centimetres' thickness of the cap of the tumulus, water infiltration velocities are required of between 0·002 cm s−1 for an uplifted stratum of 2 cm thickness, and 0·03 cm s−1 for 30 cm thickness. These velocities imply the existence of very slow rates of infiltration and/or capillary movement of water within the gypsiferous layer. The secondary microcrystalline gypsum is precipitated in the intercrystalline and intracrystalline voids of the gypsum crystals, producing an increase in porosity and associated volume that causes the doming of the gypsiferous layer. The development of tumuli is a cyclic process which is favoured by a sequence of short wet and dry intervals which, in turn, facilitate the almost simultaneous processes of dissolution and precipitation. These conditions predominate in arid and semiarid climates where intense evaporation can occur suddenly following sporadic infiltration. Copyright © 1999 John Wiley & Sons, Ltd.

Sorptivity of fly ash concretes

A factorial experiment was designed to measure the sorptivity of cement and fly ash concretes in order to compare the durability of fly ash concrete against the cement concrete. Sorptivity measurements based on the capillary movement of water was made on three grades of cement concrete and six grades of fly ash mixes. The effect of curing was also studied by treating the samples in two curing conditions. A functional relationship of sorptivity against the strength, curing condition and fly ash content has been presented. The results were useful to analyse the factors influencing the durability of cement and fly ash concretes and to explain why some of the previously reported findings were contradictary. Curing conditions have been found to be the most important factor that affected the durability properties of fly ash concrete. When proper curing was provided, a mix with 40% fly ash was found to reduce the sorptivity by 37%. Under inadequate curing the sorptivity was found to increase by 60%. The influence of curing on cement concrete was found to be of much less importance.

Use of an integrated transient flow and water budget procedure to predict and partition components of local recharge

A combined transient flow and water budget (TFWB) method and accounting procedure was developed and used to measure and partition the components of recharge to a sand and gravel aquifer underlying about 6.0 m of glacial till overlain by a nearly level land surface. The TFWB procedure was used to evaluate and quantify the dynamic interaction between surface recharge, till water level (at 2–4 m), and water cycling within the soil and vadose zone. Site-specific recharge activity was highly dependent upon surface microtopography. However, the homogenizing effect of the water table, measured by capillary movement of water through the vadose and soil zone, substantially offset the effects of surface and soil spatial variability and allowed relatively uniform estimates of local recharge at individual measurement sites. Substantial internal cycling of water within the soil and vadose zone was caused by the interaction of surface infiltration variability and water redistribution at the water table, even for measurement sites having little direct surface recharge activity. Through internal cycling, a single volume of water originating at the surface frequently passed through more than one soil and vadose profile during the recharge process. By applying TFWB procedures for the full soil and vadose zone between the surface to the water table, good estimates of local recharge to the Carrington aquifer could be made for the experimental area using few measurement sites.

Use of a microtensiometer technique to study hydraulic lift in a sandy soil planted with pearl millet (Pennisetum americanum [L.] Leeke)

A pot experiment was carried out with pearl millet (Pennisetum americanum [L.] Leeke) growing in a sandy soil in which the upper (topsoil) and lower (subsoil) parts of the pots were separated by a perlite layer to prevent capillary water movement. Using microtensiometers a study was made to establish whether it was possible to measure hydraulic lift by which the upper part of the soil was rewetted when water was supplied exclusively to the lower part of the soil.

Evaluation of a simulation model for prediction of chlorsulfuron fate in an Umbrian soil

A mathematical model described by Nicholls et al. ( Pestic. Sci., 12 (1982) 484–494) has been used to simulate the movement and the degradation of chlorsulfuron in an Umbrian soil, following application to the soil surface in autumn. Experiments were also performed on soil columns that had been surface-treated with chlorsulfuron and irrigated daily with water doses corresponding to the pluviometric records. The comparison between experimental and simulation data suggests that the model gives a reasonable description of the fate of chlorsulfuron and that it should prove of value in assessing variations in pesticide movement after different periods of application and at different sites. The differences found in the bottom layers of the columns could be due to the fact that capillary water movement is affected by the ending of the soil columns. The physical model could show a lower chlorsulfuron mobility in deeper layers where the stratum of soil ends. A defect in the physical model may have been responsible for the observed differences.

Seepage scald in southeastern Australia

This study addresses the problem of seepage scald in southeastern New South Wales. Limited information was available on soil and hydrological properties of these areas and a case study of the Yarralaw seepage scald was undertaken to answer questions concerning the scald's origin, the threat of scald expansion and possible offsite effects. The results have application to a number of similar sites in southeastern New South Wales. Scald formation was not related to any particular soil property inherent to the scalded area. Grassland and scald soil profiles were similar, with the major difference being the surface horizon. The grassland surface was relatively permeable but the scald surface was sodic, highly dispersive and compacted. As a result, it had lower permeability than the grassland. Soil salt loads were high only in the surface horizons of the scald. The water table in the lower catchment, even at its lowest level, was within 2 m of the ground surface. Upward capillary water movement is causing the salinity, but the salinity is confined to the scald because downward leaching in the grassland keeps the surface of these areas relatively salt-free. The areal extent of the Yarralaw seepage scald has been stable since 1962. High runoff conditions in the future may cause further scald expansion and it is important that reasonable measures be taken to prevent this. However, scald growth appears to be catastrophic in nature, with the majority of the damage occurring in a relatively short period of time in the early stage of formation. On the scald surface, the degradation is a progressive process but scald expansion appears to be catastrophic. This type of formation has important implications for management and emphasizes the need for seepage scald prevention.

Modelling soil-water-plant relationships in the Cerrado soils of Brazil: The case of maize ( Zea mays L.)

A soil-water balance simulation model developed for the Cerrado soils of central Brazil is presented. The model calculates daily soil water evaporation, plant transpiration and soil-water balance for fourteen soil layers of 15 mm each. The model includes a subroutine to calculate capillary water movement. Computer simulations of daily soil water levels at five soil depths (15, 30, 45, 60 and 90 cm) for a field of maize are compared with actual field measurements over an 80-day period. Results indicated that the developed model can, in general, estimate the soil-water balance of the various depths within ± 10% of actual measurements.

Effect of Constant Moisture Levels on Pythium Rot of Peanut Pods

Different constant levels of topsoil moisture were established by upward capillary movement of water from a basin through soil columns of different heights and were used to determine the influence of soil moisture on development of rot of peanut pods by Pythium myriotylum. Roots obtained water from a wet subsoil, whereas pods developed in a Pythium-infested, sandy, well-aerated topsoil. The wetter the topsoil, the higher the incidence of infected pods. However, some pod rot developed even in soil drier than the wilting range for mesophytes.