A Comparison of Indirect Watering Devices for Benefiting Newly Transplanted Urban Trees

2019 ◽  
Vol 45 (4) ◽  
Author(s):  
Shaik Hossain ◽  
H. Christoph Stuhlinger ◽  
Matthew Olson ◽  
Benjamin Babst

Three types of indirect watering devices were compared to evaluate their performance and to determine their benefits to newly transplanted river birch (Betula nigra) trees grown in containers with well drained compost in a controlled greenhouse experiment. Two examples of each device type were used to water trees in this study: upright bags, ring bags, and open tubs. Watering device characteristics, including purchase cost, weight, capacity, and drainage times, were measured prior to installing the devices around the trees. Tree stem heights and calipers, along with leaf coverage and leaf water potential, were measured to determine any growth or water stress differences associated with watering treatments. There was substantial variation in costs and drainage times among watering devices, with ring bags being the least expensive and draining water completely during the drainage test. However, there was no evidence that watering devices benefited tree growth, leaf rating, or water stress in comparison with direct watering, with the possible exception of Treegator ring bags, which may have reduced water stress marginally. Although water release from some of the indirect watering devices was much slower than direct watering, water release from all of the devices was completed within ten hours, which is too rapid to reduce the frequency of watering in our experiment. The major benefits of these devices are slower release of water to the soil, with reduced operator time required, and more infiltration into the soil and root zone, which avoids the surface runoff caused by quick hose (direct) watering.

Author(s):  
Valery Yashin

Представлены материалы исследований формирования режима влажности и динамики грунтовых вод орошаемых солонцовых комплексных почв при различных способах полива, проведенные в Волгоградском Заволжье. Установлена значительная неравномерность распределения влажности почвы при поливах дождеванием. Отмечается поверхностный сток по микрорельефу до 30% от поливной нормы, что приводит к недостаточности увлажнения корневой зоны на солонцах и переувлажнению почв в понижениях микрорельефа и потере оросительной воды на инфильтрационное питание грунтовых вод.The article presents the materials of research on the formation of the humidity regime and dynamics of ground water of irrigated saline complex soils under various irrigation methods, conducted in the Volgograd Zavolzhye. A significant unevenness in the distribution of soil moisture during irrigation with sprinkling has been established. There is a surface runoff on the microrelief of up to 30% of the irrigation norm, which leads to insufficient moisture of the root zone on the salt flats and waterlogging of the soil in the microrelief depressions and loss of irrigation water for infiltration feed of ground water.


2011 ◽  
Vol 47 (1) ◽  
pp. 1-25 ◽  
Author(s):  
M. K. V. CARR ◽  
J. W. KNOX

SUMMARYThe results of research on the water relations and irrigation needs of sugar cane are collated and summarized in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information on the centres of production of sugar cane is followed by reviews of (1) crop development, including roots; (2) plant water relations; (3) crop water requirements; (4) water productivity; (5) irrigation systems and (6) irrigation scheduling. The majority of the recent research published in the international literature has been conducted in Australia and southern Africa. Leaf/stem extension is a more sensitive indicator of the onset of water stress than stomatal conductance or photosynthesis. Possible mechanisms by which cultivars differ in their responses to drought have been described. Roots extend in depth at rates of 5–18 mm d−1 reaching maximum depths of > 4 m in ca. 300 d providing there are no physical restrictions. The Penman-Monteith equation and the USWB Class A pan both give good estimates of reference crop evapotranspiration (ETo). The corresponding values for the crop coefficient (Kc) are 0.4 (initial stage), 1.25 (peak season) and 0.75 (drying off phase). On an annual basis, the total water-use (ETc) is in the range 1100–1800 mm, with peak daily rates of 6–15 mm d−1. There is a linear relationship between cane/sucrose yields and actual evapotranspiration (ETc) over the season, with slopes of about 100 (cane) and 13 (sugar) kg (ha mm)−1 (but variable). Water stress during tillering need not result in a loss in yield because of compensatory growth on re-watering. Water can be withheld prior to harvest for periods of time up to the equivalent of twice the depth of available water in the root zone. As alternatives to traditional furrow irrigation, drag-line sprinklers and centre pivots have several advantages, such as allowing the application of small quantities of water at frequent intervals. Drip irrigation should only be contemplated when there are well-organized management systems in place. Methods for scheduling irrigation are summarized and the reasons for their limited uptake considered. In conclusion, the ‘drivers for change’, including the need for improved environmental protection, influencing technology choice if irrigated sugar cane production is to be sustainable are summarized.


2020 ◽  
Author(s):  
Jing Yan ◽  
Nathaniel A. Bogie ◽  
Teamrat Ghezzehei

Abstract. Most plants derive their water and nutrient needs from soils, where the resources are often scarce, patchy, and ephemeral. In natural environments, it is not uncommon for plant roots to encounter mismatched patches of water-rich and nutrient-rich regions. Such an uneven distribution of resources necessitates plants to rely on strategies that allow them to explore and acquire nutrients from relatively dry patches. We conducted a laboratory study to provide a mechanistic understanding of the biophysical factors that enable this adaptation. We grew plants in split-root pots that permitted precisely controlled spatial distributions of resources. The results demonstrated that spatial mismatch of water and nutrient availability does not cost plant productivity compared to matched distributions. Specifically, we showed that nutrient uptake is not reduced by overall soil dryness, provided that the whole plant has access to sufficient water elsewhere in the root zone. Essential strategies include extensive root proliferation towards nutrient-rich dry soil patches that allows rapid nutrient capture from brief pulses. Using high-frequency water potential measurements, we also observed nocturnal water release by roots that inhabit dry and nutrient-rich soil patches. Soil water potential gradient is the primary driver of this transfer of water from wet to dry soil parts of the root zone, which is commonly known as hydraulic redistribution (HR). The occurrence of HR prevents the soil drying from approaching the permanent wilting point, and thus supports root functions and enhance nutrient availability. Our results indicate that roots facilitate HR by increasing root-hair density and length and deposition of organic coatings that alter water retention. Therefore, we conclude that biologically-controlled root adaptation involves multiple strategies that compensate for nutrient acquisition under mismatched resource distributions. Based on our findings, we proposed a nature-inspired nutrient management strategy for significantly curtailing water pollution from intensive agricultural systems.


Soil Research ◽  
1985 ◽  
Vol 23 (3) ◽  
pp. 373 ◽  
Author(s):  
WC Boughton ◽  
DM Freebairn

Five-min recession constants were calculated for surface runoff and interflow using hydrographs of runoff from five 1-ha catchments at Greenmount near Toowoomba in south-east Queensland. The recession constants were converted to half-flow periods, i.e. the time required for flow rate to halve during an exponential recession. The half-flow periods of surface runoff and interflow on the 1 ha catchment are compared with published data from catchments of much larger size in New South Wales, and it is shown that the ratio of interflow half-flow period to surface runoff half-flow period does not vary much over six orders of magnitude of catchment size. Calculations of maximum rates of interflow and volumes of interflow storage show that both rates and volumes are possible in the plough depth of surface soil. The results support the evidence of interflow obtained earlier in unit hydrograph studies of runoff on these same catchments.


2011 ◽  
Vol 48 (2) ◽  
pp. 222-237 ◽  
Author(s):  
ALEMTSEHAY TSEGAY ◽  
DIRK RAES ◽  
SAM GEERTS ◽  
ELINE VANUYTRECHT ◽  
BERHANU ABRAHA ◽  
...  

SUMMARYAt various locations in North Ethiopia (Tigray), field experiments were conducted from 2006 to 2009 to assess the crop response to water stress of tef (Eragrostis tef (Zucc.) Trotter) under rainfed, fully irrigated and deficit irrigation conditions. Observed soil water content (SWC), canopy cover (CC), biomass production (B) and final grain yield (Y) were used to calibrate and validate AquaCrop for tef. Data from an experiment in a controlled environment in 2008 were also considered in the calibration process. Simulations of SWC, CC, B and Y were evaluated by determining the index of agreement, the root mean square error, the coefficient of determination and the Nash–Sutcliffe efficiency. The statistical parameters showed an adequate fit between observations and simulations. The model was able to simulate for tef growing under rainfed condition the observed fast drop in SWC and CC when the rains ceased. The overall goodness of fit between the observed and simulated CC and SWC indicated that the thresholds for root zone depletion at which water stress (i) affects canopy development, (ii) induces stomata closure and (iii) triggers early canopy senescence were well selected. The normalised biomass water productivity (WP*) for tef was 14 g m−2 for the local variety and 21 g m−2 for the improved variety, which is a lot smaller than the WP* expected for C4 plants (30–35 g m−2). The results revealed an increase of 27% in reference harvest index (HIo) of tef in response to mild water stress during the yield formation of up to 33%. However, severe water stress causing stomata closure had a negative effect on HIo. Once it is properly calibrated, AquaCrop can provide room to improve the water productivity of tef by developing guidelines for good agricultural management strategies.


1991 ◽  
Vol 21 (1) ◽  
pp. 53-57 ◽  
Author(s):  
N. J. Livingston ◽  
E. de Jong

Reversible changes in cell wall water content, elasticity, and osmotic adjustment are all important drought tolerance mechanisms. Pressure chambers have been used extensively to generate water-release curves from which these basic water relations parameters are derived. Major limitations of this technique include the considerable time required to generate water-release curves and the difficulty in avoiding damage to tissue during the process. A simple and practical technique is descried that overcomes these limitations and allows the routine and rapid generation of water-release curves. Needles were removed from hydrated black spruce (Piceamariana (Mill.) B.S.P.) shoots, weighed on a precision balance, and suspended above unsaturated salt solutions of known molality in sealed test tubes held at 5 °C. Eighteen solutions were used with water potentials ranging from −0.09 to −4.67 MPa. Once needles had equilibrated with air above the salt solution (8–30 h depending on needle age), they were weighed and oven-dried. Water-release curves were obtained by plotting paired values of needle relative water content and solution water potential. Typically, 35 curves were generated over 3 days compared with 7 curves generated using a pressure chamber over the same period. There was excellent agreement between methods in estimates of elastic modulus, osmotic potential, and apoplastic water content.


2006 ◽  
Vol 24 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Edward F. Gilman ◽  
Patti J. Anderson

Abstract Trees that were root pruned regularly throughout the production period grew at a slower rate than trees that were not root pruned, but root pruning only in the last year of production did not affect trunk and canopy growth. Trees with root-pruning fabric installed under liners at planting grew at the same rate as trees without fabric during 39 months of field production. Hand spade root pruning throughout the production period increased the number of small diameter (< 3mm) roots and decreased the number of large diameter roots in the root ball compared to trees that were not root pruned. Root pruning only in the last year of production reduced the number of large diameter roots but did not increase the number of small diameter roots. Fabric had no impact on the root system. Root pruning with a hand spade throughout production or only in the last year of production reduced water stress significantly in trees following digging compared to trees not root pruned during production. Root-pruning fabric installed under liners at planting reduced stress following digging 39 months later, but only on two of the days when water stress was measured.


2012 ◽  
Vol 30 (3) ◽  
pp. 137-145 ◽  
Author(s):  
Bruce L. Dunn ◽  
Janet C. Cole ◽  
Mark E. Payton

Experiments were conducted to evaluate potential means for reducing moisture stress in nine herbaceous and woody ornamental species. In Expt. 1 (2009), a water only control treatment and the antitranspirant Stasis™ at two different rates were applied as a drench application before inducing drought stress in the greenhouse by withholding water for two weeks. No significant differences in visual ratings in relation to plant quality were detected among treatments 5 days after application for any species. At 10 days after treatment, visual ratings were better for Veronica at the lower Stasis™ rate, Hibiscus at the low and higher Stasis™ rate, and Weigela at lower and higher Stasis™ rate compared to no Stasis™. At 15 days after treatment, visual ratings were worse for Coreopsis, Rudbeckia, and Salvia at both low and high Stasis™ rates; but, were better for Hibiscus and Weigela at the lower and higher Stasis™ rates compared to the no Stasis™ treatment. In Expt. 2 (2010), the antitranspirants Stasis™ and Root-Zone were evaluated along with a no antitranspirant and well-watered control treatments at single rates. No significant differences in visual ratings existed among treatments five days after application for any species. At 10 days after treatment, visual ratings were higher for Coreopsis, Forsythia, Nandina, and Weigela with Stasis™ or Root-Zone compared to no antitranspirant application. Visual ratings for Rudbeckia and Salvia with Stasis™, and Euonymus with Root-Zone were also better than the stress treatment at 10 days after treatment. At 15 days after treatment, visual ratings were higher for Coreopsis and Salvia with Stasis™ compared to the stress treatment. Rudbeckia, Euonymus, and Weigela with Stasis™ or Root-Zone and Nandina with Root-Zone all had better visual ratings than the stress treatment. Evapotranspiration was not reduced for any Stasis™ or Root-Zone treatment for any species in either experiment compared to control stress treatments.


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