Controlled Water Table Irrigation System Effect on Growing Medium Water Potential

The CWT irrigation system consists of a capillary mat placed on a level bench so one side extends over the edge of the bench into a trough containing a nutrient solution maintained at a controlled distance below the bench. The nutrient solution is drawn by capillarity up to and over the bench surface. As plants use the nutrient solution or as water evaporates from the media, it is replaced from the trough. The automatic system maintains a constant air/water ratio in the growing media. Geraniums were grown in a peat based media in 15-cm pots at 0, 2, and 4 cm CWT. In a separate study, the water potential was determined in two media. Water potential was determined at the bottom, middle, and top of the container at 0, 2 and 4 cm CWT every 2.5 hrs during the light period. Geraniums at 0 and 2 cm had the greatest leaf area and dry weight. The 0- and 2-cm treatments were >25% greater than plants at 4 cm CWT. The roots of plants at 0 cm CWT were concentrated at 2–4 cm above the bottom of the container, whereas roots at 2 cm CWT uniformily extended from the center to the bottom. Water potential was about the same in each media within each CWT treatment. The water potential from top to bottom decreased slightly about midafternoon on a sunny day when water demand was the greatest. Media at 0 CWT at the container bottom had 0 water potential; whereas the water potential at 2 and 4 CWT had a lower water potential.

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681 Controlling Stress in Container-grown Plants

HortScience ◽

10.21273/hortsci.35.3.516b ◽

2000 ◽

Vol 35 (3) ◽

pp. 516B-516

Author(s):

Jack W. Buxton

Keyword(s):

Water Potential ◽

Nutrient Solution ◽

Water Demand ◽

Automatic System ◽

Irrigation System ◽

Dry Weight ◽

Light Period ◽

Media Study ◽

The Media ◽

Water Ratio

The controlled water table irrigation system (CWT) consists of a capillary mat placed on a level bench so one side extends over the edge of the bench into a trough containing a nutrient solution maintained at a controlled distance below the bench. The nutrient solution is drawn by capillarity up to and over the bench surface. As plants use the nutrient solution or as water evaporates from the media, it is replaced from the trough. The automatic system maintains a constant air/water ratio in the growing media. Study 1: Geraniums were grown in 15-cm pots at 0, 2, and 4 cm CWT. Geraniums at 0 and 2 cm CWT had the greatest leaf area and dry weight. Plants at 0 and 2 cm CWT were more than 25% greater at 4 cm CWT. The roots of plants at 0 cm CWT were concentrated at 2 to 4 cm above the bottom of the container; whereas roots at 2 cm CWT uniformly extended from the center to the bottom. Study 2: Water potential in a coarse and fine textured media was determined at the bottom, middle and top of the container at 0, 2, and 4 cm CWT every 2.5 h during the light period. Water potential was about the same in each media within each CWT treatment. At the container bottom at 0 CWT water potential was 0; whereas the water potential at 2 and 4 CWT was lower. The water potential from top to bottom decreased slightly about mid afternoon on a sunny day when water demand was the greatest. The CWT system is potentially a commercially adaptable irrigation system for container crops. It also is a cheap, reliable tool for studying water stress on the crop growth and quality.

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Irrigation of Geraniums with an Automatic Controlled Water Table System

HortScience ◽

10.21273/hortsci.33.3.522d ◽

1998 ◽

Vol 33 (3) ◽

pp. 522d-522 ◽

Cited By ~ 1

Author(s):

J.W. Buxton ◽

D.L. Ingram ◽

Wenwei Jia

Keyword(s):

Water Potential ◽

Leaf Area ◽

Water Table ◽

Nutrient Solution ◽

Irrigation System ◽

Central Area ◽

Dry Weight ◽

Trickle Irrigation ◽

Run Off ◽

Optimum Water

Geraniums in 15-cm pots were irrigated automatically for 8 weeks with a Controlled Water Table (CWT) irrigation system. Plants were irrigated with a nutrient solution supplied by a capillary mat with one end of the mat suspended in a trough below the bottom of the pot. The nutrient solution remained at a constant level in the trough. Nutrient solution removed from the trough was immediately replaced from a larger reservoir. The vertical distance from the surface of the nutrient solution and the bottom of the pot determined the water/air ratio and water potential in the growing media. Treatments consisted of placing pots at 0, 2, 4, and 6 cm above the nutrient solution. Control plants were irrigated as needed with a trickle irrigation system. Geraniums grown at 0,2 and 4 CWT were ≈25% larger than the control plants and those grown at 6 CWT as measured by dry weight and leaf area. Roots of plants grown at 0 CWT were concentrated in the central area of the root ball; whereas roots of plants in other treatments were located more near the bottom of the pot. Advantages of the CWT system include: Plant controlled automatic irrigation; no run off; optimum water/air ratio.

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Production of Vegetable Transplants with the Controlled Water Table Irrigation System

HortScience ◽

10.21273/hortsci.31.4.633a ◽

1996 ◽

Vol 31 (4) ◽

pp. 633a-633

Author(s):

Jack W. Buxton ◽

Wenwei Jia

Keyword(s):

Water Table ◽

Nutrient Solution ◽

Production Systems ◽

Irrigation System ◽

Root Penetration ◽

Growing Medium ◽

Cabbage Seed ◽

The Media ◽

Greenhouse Vegetable ◽

Solution Surface

Cabbage seed was germinated and grown to transplanting size in a 98-cell tray using an automatic irrigation system based on the principle of maintaining a constant water table (CWT) relative to the growing medium in transplant trays. Seedlings obtained a nutrient solution from a capillary mat with one end suspended in a trough containing the solution. The distance between the nutrient solution surface and the transplant tray bottom was regulated with a water level controller. The nutrient solution was resupplied from a larger reservoir. A polyester material on top of the capillary mat allowed solution movement to the roots but prevented root penetration into the mat. The water table placement below the tray determined the water content in the growing medium. Seedling growth was evaluated using two growing media combined with two water table placements. Excellent quality seedlings were produced; the CWT irrigation system satisfactory provided water and nutrients for the duration of the crop. The only problems observed were dry cells, less than 2%, because of no media–mat contact and algae growth on the media surface using the higher water table. The CWT irrigation system is adaptable to existing greenhouse vegetable transplant production systems. It is automatic and can provide a constant optimum amount of moisture for seedling growing. It can be adjusted for phases of seedling growing such as more water during germination and can create water stress near transplanting time to either harden off or hold plants because of unfavorable planting conditions.

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Fluctuating Controlled Water Table Irrigation

HortScience ◽

10.21273/hortsci.39.4.769d ◽

2004 ◽

Vol 39 (4) ◽

pp. 769D-770

Author(s):

Jack W. Buxton* ◽

Janet Pfeiffer ◽

Darrell Slone

Keyword(s):

Water Potential ◽

Leaf Area ◽

Water Table ◽

Water Surface ◽

Irrigation System ◽

Dry Weight ◽

Control Treatment ◽

Optimum Placement ◽

Growing Medium ◽

Rate Of Movement

A controlled water table irrigation system (CWT) automatically provides water to plants. One edge of a capillary mat, on the bench surface, draws water from a trough (water table) below the bench. Each treatment trough was 30 cm long. As the distance between the water surface and the bench surface increases, the water in the growing medium decreases, the air increases; and the water potential decreases. In previous studies a constant CWT of 2 cm below the bench surface was the optimum placement for producing 15-cm pots of geranium. In this study the water table fluctuated between two distances below the bench surface. The fluctuating treatments were 2 cm to 3 cm, 2 cm to 4 cm, and 1 cm to 4 cm. The control treatment remained at a constant 2 cm below the bench surface. The fluctuating treatments were established by using two liquid level controllers connected to a switching mechanism that allowed the water table to fluctuate between the treatment settings. The rate of movement from the higher level to the lower level was determined by the rate of transpiration and evaporation occurring in individual treatments. The amount of water used for each treatment was determined by counting the number of times the solenoid turned on and multiplying this by the amount of water added to the trough. The leaf area and dry weight were the same for plants grown in 2 cm, 2 to 3 cm, and 2 to 4 cm treatments and these treatments were significantly greater than plants in the 1 to 4 cm treatment. The amount of water used by all treatments was nearly the same.

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419 A Laboratory Demonstration of Water Stress on Plant Growth

HortScience ◽

10.21273/hortsci.35.3.465d ◽

2000 ◽

Vol 35 (3) ◽

pp. 465D-465

Author(s):

J.W. Buxton ◽

T.D. Phillips

Keyword(s):

Water Stress ◽

Plant Growth ◽

Water Potential ◽

Nutrient Solution ◽

Irrigation System ◽

Net Photosynthesis ◽

Science Courses ◽

Vertical Distance ◽

Plant Water Potential ◽

Solution Surface

Students in plant science courses have difficulty thoroughly understanding the effect of water stress on net photosynthesis and its consequences—reduced plant growth, productivity, quality, and profit. A laboratory demonstration utilizing a controlled water table irrigation system (CWT) provides a nearly constant plant water potential. Pots are placed on a capillary mat with one end suspended in a trough with nutrient solution. The vertical distance from the solution surface to the pot bottom determines the water potential; the water potential is 0 when the pot bottom is at the same level as the nutrient solution. The greater the vertical distance from solution to the pot bottom, the lower the water potential. For this demonstration, the bench was sloped from 0 to 10 cm above the solution over a distance of 90 cm. Corn, squash, soybean, fescue, and marigold seed were directly sown to either 9- or 15-cm pots and then placed on the CWT sloped bench at five vertical distances above the solution. Weekly, students observed plant growth and at the end of 8 weeks evaluated root and shoot growth. For all species, plant growth was indirectly related to the distance above the nutrient solution. Plants at near 0 water potential were much larger than those grown 8 to 10 cm above the solution.

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456 An Automatic, Controlled Water-Table Irrigation System for Vegetable Transplant Production

HortScience ◽

10.21273/hortsci.34.3.523c ◽

1999 ◽

Vol 34 (3) ◽

pp. 523C-523

Author(s):

J.W. Buxton ◽

Wenwei Jia

Keyword(s):

Water Table ◽

Nutrient Solution ◽

Irrigation System ◽

Growing Media ◽

System A ◽

Fixed Distance ◽

Run Off ◽

Vegetable Seed ◽

Growth Of Seedlings ◽

Water Ratio

The controlled water-table irrigation (CWT) system was evaluated for vegetable seed germination and transplant growth. The system is a modification of capillary mat irrigation except that the mat along one side extends over the edge of the bench into a narrow trough running along the side of the bench. The nutrient solution level in the trough is controlled by a liquid level controller, so it is at a fixed distance below the bench surface. The nutrient solution is drawn by capillarity from the trough upward to the bench surface and then moves by capillarity to the opposite side of the bench. The system automatically maintains a constant air: water ratio in the growing media. Seeds of broccoli, tomato, and pepper were germinated in a 96-cell plug tray and grown to transplanting stage with the CWT system. A factorial experiment consisted of two growing media combined with CWT treatments of 2 and 4 cm. Excellent germination and high-quality seedlings were produced with all treatments. No differences were observed in growth of seedlings at 2 vs. 4 cm or between the two growing media. The CWT system is capable of maintaining a constant uniform water: air ratio in all plug cells on a commercial growing bench. Nutrient solution does not run off the bench. The CWT potentially is an excellent system for the irrigation of vegetable transplants.

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The study of important agronomic traits by multivariate analysis in winter rapeseed cultivars

JOURNAL OF ADVANCES IN AGRICULTURE ◽

10.24297/jaa.v1i1.4240 ◽

2014 ◽

Vol 1 (1) ◽

pp. 20-24

Author(s):

Gader Ghaffari ◽

Farhad Baghbani ◽

Behnam Tahmasebpour

Keyword(s):

Water Potential ◽

Water Deficit ◽

Leaf Water Potential ◽

Seed Weight ◽

Dry Weight ◽

Total Variance ◽

Water Deficit Stress ◽

The Third ◽

High Eigenvalue ◽

Winter Rapeseed

In order to group winter rapeseed cultivars according to evaluated traits, an experiment was conducted in the Research Greenhouse of Agriculture Faculty, University of Tabriz - IRAN. In the experiment were included 12 cultivars of winter rapeseed and 3 levels of water deficit stress. Gypsum blocks were used to monitor soil moisture. Water deficit stress was imposed from stem elongation to physiological maturity. According to the principal component analysis, five principal components were chosen with greater eigenvalue (more than 0.7) that are including 81.34% of the primeval variance of variables. The first component that explained the 48.02% of total variance had the high eigenvalue. The second component could justify about 13.64% of total variance and had positive association with leaf water potential and proline content and had negative relationship with leaf stomatal conductivity. The third, fourth and fifth components expressed around, 10.18, 4.83 and 4.68% of the total variance respectively. The third component had the high eigenvalue for plant dry weight. The fourth component put 1000-seed weight, seed yield, Silique per Plant and root dry weight against plant dry weight, chlorophyll fluorescence and leaf water potential. The fifth component had the high eigenvalue for root dry weight, root volume and 1000-seed weight.

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UTILIZATION OF RAWAPENING PEAT FOR NUTRIENT BLOCK AS A MEDIA NURSERIES Anthocephalus cadaba and Paraserianthes falcataria

Jurnal Rekayasa Lingkungan ◽

10.29122/jrl.v8i1.1980 ◽

2018 ◽

Vol 8 (1) ◽

Author(s):

E. Hanggari Sittadewi., dkk

Keyword(s):

Plant Growth ◽

Physical Properties ◽

Environmental Degradation ◽

Leaf Growth ◽

Rehabilitation Program ◽

Paraserianthes Falcataria ◽

Land Rehabilitation ◽

Mining Areas ◽

Growing Medium ◽

The Media

Nutrient Block is a growing medium product in the form of a square (25 x 25 cm) or cylindrical (diameter = 20 cm, height = 25 cm) made of peat which has been composted, plus adhesive gypsum or tapioca waste. Nutrient Block is designed to support the post mining land rehabilitation program that is now threatening the environmental degradation in mining areas. Nutrient Block products has been proved good for growth because of the media in addition to having physical properties that are capable of storing large amounts of water, contain enough nutrients in the form available to plants,so it can support plant growth. Results of the Nutrient Block application test to Jabon (Anthocephalus cadaba) and Sengon (Paraserianthes falcataria) plants showed that good performance, both plant height and diameter of trees and leaf growth in plants Jabon appear healthy and getting wider.keywords: nutrient block, post-mining land rehabilitation. Paraserianthes falcataria, Anthocephalus cadaba

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Swine Effluent for Tomato in a Plasticulture Production System

HortScience ◽

10.21273/hortsci.33.3.524a ◽

1998 ◽

Vol 33 (3) ◽

pp. 524a-524 ◽

Cited By ~ 1

Author(s):

Kent Cushman ◽

Thomas Horgan

Keyword(s):

Production System ◽

Irrigation System ◽

Dry Weight ◽

Water Source ◽

Nutrient Concentrations ◽

Plastic Mulch ◽

Tomato Production ◽

Swine Effluent ◽

Soluble Fertilizer ◽

Source Number

Tomato was grown in Fall 1997 with swine effluent or commercial soluble fertilizer in a plasticulture production system. Four cultivars, `Mountain Delight', `Celebrity', `Equinox', and `Sunbeam', were transplanted to raised beds with plastic mulch and drip irrigation. Preplant fertilizer was not applied. Effluent from the Wiley L. Bean Swine Demonstration Unit's secondary lagoon was filtered through in-line screen filters and applied directly to the plants through the irrigation system. Toward the end of each application, sodium hypochlorite was injected in the line to achieve a free chlorine concentration of ≈1%. Clogging of filters or drip emitters did not occur. Control plants received 100 ppm N from soluble fertilizer injected in irrigation lines supplied by a municipal water source. Number and weight of tomatoes from plants receiving swine effluent were equal to that of plants receiving soluble fertilizer. No differences in fruit quality were evident between treatments. Plant dry weight was also equal for three out of four cultivars. No differences in soil characteristics were detected between treatments after the study. Chemical analysis of the effluent showed a pH of 7.8 and nutrient concentrations of ≈110 ppm NH4-N, 57 ppm P2O5, 150 ppm K2O, and trace amounts of Cu and Zn. Though no differences in yield were detected in this study, the effluent's high pH and high NH4-N content need to be managed more closely for commercial tomato production.

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Effects of Leachate Fertigation and the Addition of Hydrogen Peroxide on Growth and Nutrient Balance in Dracaena deremensis Potted Plants

Agronomy ◽

10.3390/agronomy11010127 ◽

2021 ◽

Vol 11 (1) ◽

pp. 127

Author(s):

Pedro García-Caparrós ◽

Cristina Velasquez Espino ◽

María Teresa Lao

Keyword(s):

Nutrient Solution ◽

Soluble Sugar ◽

Nutrient Balance ◽

Treatment Plant ◽

Dry Weight ◽

Sugar Concentration ◽

Control Treatment ◽

Peat Moss ◽

Clear Trend ◽

Total Soluble Sugar

The reuse of drainages for cultivating more salt tolerant crops can be a useful tool especially in arid regions, where there are severe problems for crops water management. Dracaena deremensis L. plants were cultured in pots with sphagnum peat-moss and were subjected to three fertigation treatments for 8 weeks: control treatment or standard nutrient solution (D0), raw leachates from Chrysalidocarpus lutescens H. Wendl plants (DL) and the same leachate blending with H2O2 (1.2 M) at 1% (v/v) (DL + H2O2). After harvesting, ornamental and biomass parameters, leaf and root proline and total soluble sugar concentration and nutrient balance were assessed in each fertigation treatment. Plant height, leaf and total dry weight had the highest values in plants fertigated with leachates with H2O2, whereas root length, leaf number, RGB values and pigment concentration declined significantly in plants fertigated with leachates from C. lutescens with or without H2O2. The fertigation with leachates, regardless of the presence or absence of H2O2 increased root and leaf proline concentration. Nevertheless, root and leaf total soluble sugar concentration did not show a clear trend under the treatments assessed. Regarding nutrient balance, the addition of H2O2 in the leachate resulted in an increase in plant nutrient uptake and efficiency compared to the control treatment. The fertigation with leachates with or without H2O2 increased nitrogen and potassium leached per plant compared to plants fertigated with the standard nutrient solution. The reuse of drainages is a viable option to produce ornamental plants reducing the problematic associated with the water consumption and the release of nutrients into the environment.

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