scholarly journals A Two-dimensional, Dynamic Model for Root Growth Distribution of Potted Plants

1993 ◽  
Vol 118 (2) ◽  
pp. 181-187 ◽  
Author(s):  
De-Xing Chen ◽  
J. Heinrich Lieth
Keyword(s):  
Spatial Distribution ◽  
Root Growth ◽  
Soil Water Potential ◽  
Extension Rate ◽  
Root Weight ◽  
Two Dimensional ◽  
Weight Density ◽  
Whole Plant ◽  
Root Weight Density ◽  
Growth Distribution

A two-dimensional mathematical model was developed to describe the time course of root growth and its spatial distribution for container-grown plants, using chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] as the model system. Potential root growth was considered as consisting of several concurrent processes, including branching, extension, and death. Branching rate was assumed to be related sigmoidally to existing root weight density. Root growth extension rate was assumed to be proportional to the existing root weight density above some threshold root weight density in adjacent cells. The senescence rate of root weight density was assumed to be proportional to existing root mass. The effects of soil matric potential and temperature on root growth were quantified with an exponential function and the modified Arrhenius equation, respectively. The actual root growth rate was limited by the amount of carbohydrate supplied by the canopy to roots. Parameters in the model were estimated by fitting the model to experimental data using nonlinear regression. Required inputs into the model included initial root dry weight density distribution, soil temperature, and soil water potential data. Being a submodel of the whole-plant growth model, the supply of carbohydrates from canopy to roots was required; the total root weight incremental rate was used to represent this factor. Rather than linking to a complex whole-plant C balance model, the total root weight growth over time was described by a logistic equation. The model was validated by comparing the predicted results with independently measured data. The model described root growth dynamics and its spatial distribution well. A sensitivity analysis of modeled root weight density to the estimated parameters indicated that the model was more sensitive to carbohydrate supply parameters than to root growth distribution parameters.

scholarly journals `Ben Lear' and `Stevens' Cranberry Root and Shoot Growth Response to Soil Water Potential

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 795-798 ◽  
Author(s):  
Dana L. Baumann ◽  
Beth Ann Workmaster ◽  
Kevin R. Kosola
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Area ◽  
Growth Rates ◽  
Soil Water Potential ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Water Potentials ◽  
Whole Plant

Wisconsin cranberry growers report that fruit production by the cranberry cultivar `Ben Lear' (Vaccinium macrocarpon Ait.) is low in beds with poor drainage, while the cultivar `Stevens' is less sensitive to these conditions. We hypothesized that `Ben Lear' and `Stevens' would differ in their root growth and mortality response to variation in soil water potential. Rooted cuttings of each cultivar were grown in a green-house in sand-filled pots with three different soil water potentials which were regulated by a hanging water column below a fritted ceramic plate. A minirhizotron camera was used to record root growth and mortality weekly for five weeks. Root mortality was negligible (2% to 6%). Whole plant relative growth rates were greatest for both cultivars under the wettest conditions. Rooting depth was shallowest under the wettest conditions. Whole-plant relative growth rates of `Ben Lear' were higher than `Stevens' at all soil water potentials. `Stevens' plants had significantly higher root to shoot ratios and lower leaf area ratios than `Ben Lear' plants, and produced more total root length than `Ben Lear' at all soil water potentials. Shallow rooting, high leaf area ratio, and low allocation to root production by `Ben Lear' plants may lead to greater susceptibility to drought stress than `Stevens' plants in poorly drained cranberry beds.

scholarly journals Root and nitrate-N distribution and optimization of N input in winter wheat

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bin-Bin Guo ◽  
Bei-Cheng Liu ◽  
Li He ◽  
Yang-Yang Wang ◽  
Wei Feng ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Root System ◽  
N Uptake ◽  
Root Weight ◽  
N Application ◽  
Weight Density ◽  
N Supply ◽  
Nitrate N ◽  
N Input ◽  
Root Weight Density

AbstractScientific management of nitrogen (N) fertilizer has a significant effect on yield while also reducing the environmental risks. In this study, we conducted field experiments over three years at two different sites (Zhengzhou and Shangshui) in Henan Province, China, using different N application rates (0, 90,180, 270, and 360 kg ha−1) to determine the relationships between soil N supply and N demand in winter wheat (Triticum aestivum L.). Optimal N input was then determined. Both sites showed the same trend. Namely, aboveground N uptake and soil nitrate N (NO3−-N) increased with increasing N, while NO3−-N decreased with increasing soil depth, gradually moving downwards with growth. A significant correlation (p < 0.001) between increasing aboveground N uptake and increasing NO3−-N was also observed under N application, with the best relationships occurring in the 20–60 cm layer during jointing-anthesis (R2 = 0.402–0.431) and the 20–80 cm layer at maturity (R2 = 0.474). Root weight density showed the same spatial-temporal characteristics as NO3−-N, following a unimodal trend with increasing N, and peaking at 90 kg ha−1. The root weight density was mainly distributed in the 0–60 cm layer (above 80%), with the 20–60 cm layer accounting for 30% of the total root system. In this layer, the root weight density was also significantly positively correlated with aboveground N uptake. Wheat yield reached saturation under high N (>270 kg ha−1), with a sharp decrease in N use efficiency (NUE) and linear increase in residual NO3−-N. To balance yield and the risk of environmental pollution in the experimental area, an N application rate of 180–270 kg ha−1 is recommended under sufficient irrigation, thereby supporting a well-developed root system while ensuring balance between N supply and demand.

scholarly journals Optimized Nitrogen Application Increases Soil Water Extraction by Changing in-Season Maize Root Morphology and Distribution in Rainfed Farmland

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1606
Author(s):  
Liang Tang ◽  
Haoran Sun ◽  
Ruxiao Sun ◽  
Yinan Niu ◽  
Jingrong Song ◽  
...  
Keyword(s):  
Controlled Release ◽  
Root Length ◽  
Root Length Density ◽  
Soil Layer ◽  
Water Extraction ◽  
Root Weight ◽  
Urea Treatment ◽  
Weight Density ◽  
Root Weight Density ◽  
Controlled Release Urea

The proper promotion of a deep root system is important for maize cultivation to improve water use efficiency in the arid and semi-arid Loess Plateau. Here, a field experiment was conducted to assess the effect of combined controlled release urea and normal urea on root growth and water extraction of maize in dryland fields. Maize in the combined controlled release urea and normal urea treatment had greater root systems compared to those in the normal urea treatment and no N application treatment. Compared to the urea treatment, combined controlled release urea and normal urea advanced the root length density and root weight density in the 0–10 cm soil layer at R1 stage by 30.99% and 45.03% in 2016 and by 20.54% and 19.13% in 2017. The root length density also increased at the dent stage (R5) by 52.05% and 47.75% in 2016 and 2017, and root weight density increased by 19.58% in 2016. Combined controlled release urea and normal urea promoted production of fine roots and root distribution, as well as decreased soil water storage (SWS) in the deep soil layer at the R5 stage. The grain yield was positively correlated with root length density and root weight density in the topsoil layer at the silking stage (R1) and in the whole soil profile at the R5 stage, suggesting that better root system management is helpful for increasing crop grain yield. Therefore, this work demonstrates that combined use of controlled release urea and normal urea to higher crop yields might attribute to increasing water extraction by optimizing in-season maize root morphology and distribution in the rainfed farmland of the Loess Plateau.

scholarly journals Summer Cultivation Increases Field Infiltration Rates of Water and Reduces Soil Electrical Conductivity on Annual Bluegrass Golf Greens

HortScience ◽  
2001 ◽  
Vol 36 (4) ◽  
pp. 776-779 ◽  
Author(s):  
Robert L. Green ◽  
Laosheng Wu ◽  
Grant J. Klein
Keyword(s):  
Electrical Conductivity ◽  
Bulk Density ◽  
Root Zone ◽  
Water Infiltration ◽  
Root Weight ◽  
Soil Electrical Conductivity ◽  
Annual Bluegrass ◽  
Infiltration Rates ◽  
Weight Density ◽  
Root Weight Density

Summer decline of annual bluegrass (Poa annua L.) putting greens is a major concern of golf course superintendents. Low soil water infiltration rates and high concentrations of salts in the root zone are contributing factors. This study was conducted to determine the effects of summer cultivation treatments on field infiltration rates of water, soil salinity, oxygen diffusion rates (ODR), bulk density, total and air-filled porosity, and root weight density. This research was conducted during two summer seasons (1996 and 1997) on a practice putting green located at Industry Hills Golf Courses, City of Industry, Calif. The green was constructed to U.S. Golf Association (USGA) specifications in 1978. Cultivation treatments consisted of: 1-3) water injection cultivation (WIC) applied with a Toro HydroJect every 21 d (raised position), and every 14 or 21 d (lowered position); 4) solid tine cultivation (STC) applied every 14 d; and 5) no cultivation (check). Results showed WIC and STC significantly increased field infiltration rates of water and lowered overall soil electrical conductivity of the extract (ECe) at depths of 2.5 to 7.5 cm and 7.5 to 15.0 cm in the root zone. The effects of WIC, raised position, did not differ significantly from those of STC, but infiltration rates of water were greater on all rating dates. Cultivation treatments had no significant effects on overall soil ODR, bulk density, and porosity or on overall root weight density.

Effect of time and amount of first irrigation on the root distribution and fodder yield of oats

1987 ◽  
Vol 108 (2) ◽  
pp. 299-303 ◽  
Author(s):  
B. R. Sharma
Keyword(s):  
Root Distribution ◽  
Forage Yield ◽  
Root Weight ◽  
Initial Growth ◽  
Weight Density ◽  
Fodder Yield ◽  
Use Efficiency ◽  
Root Weight Density ◽  
Better Than ◽  
Yield Of Oats

SummaryWater-use efficiency and forage yield of irrigated oats depend to a large extent on water application during initial growth. Root distribution, growth and fodder yield of oats as influenced by time and amount of first irrigation were studied in the field for 2 years. Root-weight density of each layer, profile-root-weight density and yields decreased progressively when the first irrigation was delayed. Application of a small amount of irrigation (20 mm) at day 25 proved to be better than applications of 50 or 70 mm at later stages.

Soil Water Effect on Root Activity, Root Weight Density, and Grain Yield in Winter Wheat

Crop Science ◽  
2017 ◽  
Vol 57 (1) ◽  
pp. 437-443 ◽  
Author(s):  
Yin Wu ◽  
Hezhou Wang ◽  
Xiwen Yang ◽  
Zhaojiang Meng ◽  
Dexian He
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Soil Water ◽  
Root Activity ◽  
Root Weight ◽  
Water Effect ◽  
Weight Density ◽  
Root Weight Density

Effect of drought on ericoid mycorrhizae in wild blueberry (Vaccinium angustifolium Ait.)

2003 ◽  
Vol 83 (3) ◽  
pp. 583-586 ◽  
Author(s):  
E. Jeliazkova and D. Percival
Keyword(s):  
Spatial Distribution ◽  
Soil Depth ◽  
Block Design ◽  
Soil Profiles ◽  
Root Weight ◽  
Vaccinium Angustifolium ◽  
Ericoid Mycorrhizae ◽  
Randomized Complete Block Design ◽  
Influence Of Water ◽  
Wild Blueberry

To evaluate the influence of water exclusion on the mycorrhizal coloni zations in wild blueberry, and to examine the spatial distribution of mycorrhizae among roots of wild blueberry plants that were in both the vegetative and cropping stages of production, a randomized complete block design was used. The mycorrhizal coloniz a tions were equally distributed throughout upper and lower soil profiles in both stages of production. Nevertheless, soil moisture levels in water exclusion treatments were as much as 50% lower than the control, drought stress had no effect on mycorrhizal colonization levels or on any other of the measured responses. Root weight and volume decreased as soil depth increased from 0-7.5 to 7.5-15 cm. Key words:

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