Modification of Water Application Rates and Intermittent Control for Sprinkler Frost Protection

2018 ◽  
Vol 61 (4) ◽  
pp. 1277-1285 ◽  
Author(s):  
Yongzong Lu ◽  
Yongguang Hu ◽  
Chen Zhao ◽  
Richard L. Snyder
Keyword(s):  
Control Strategy ◽  
Irrigation System ◽  
Sprinkler Irrigation ◽  
Application Rate ◽  
Intermittent Control ◽  
Water Application ◽  
Modified Model ◽  
Irrigated Area ◽  
Frost Protection ◽  
Tea Field

Abstract. To validate the feasibility of an automated frost protection sprinkler system, a sprinkler irrigation system with an optimal water application rate was designed, constructed, and tested in a tea field. A modified calculation model of the water application rate was provided by simulation with different values of airflow velocity, air temperature, air humidity, and spray water temperature. An intermittent control strategy was provided using a modified model that included the start and stop time of the system and adjustment of the water application rate. Tea field experiments were conducted to evaluate the effect of frost protection based on this control strategy during frost night events. The results showed that a variable water application rate was better suited for frost protection, and the modified intermittent control automatically regulated the water application rate. In early spring and winter heavy frost nights, the canopy temperature (Tc) of the irrigated area remained above -1.2°C and 0°C, respectively, which is higher than the critical damage temperature for tea plants. The Tc of the irrigated area was approximately 2.8°C higher than that of a non-irrigated area. Moreover, the irrigated area with the modified model had a slower temperature rise after sunrise compared with the non-irrigated area, which was beneficial for frost protection. This sprinkler control strategy is an effective frost protection method that could be applied for in tea fields in the Yangtze River region. The calculation and simulation procedure of the water application rate would be applied for constructing sprinklers for different micrometeorological environments. Keywords: Frost protection, Intermittent control, Spraying water temperature, Sprinkler irrigation system, Tea, Water application rate.

scholarly journals Cyclic Sprinkler Irrigation and Pre-irrigation Substrate Water Content Affect Water and N Leaching from Containers

1994 ◽  
Vol 12 (4) ◽  
pp. 198-202
Author(s):  
Nabila S. Karam ◽  
Alexander X. Niemiera
Keyword(s):  
Water Content ◽  
Irrigation System ◽  
Sprinkler Irrigation ◽  
Application Rate ◽  
N Leaching ◽  
Time Interval ◽  
Water Application ◽  
Total N ◽  
Continuous Irrigation ◽  
Continuous Application

Abstract A series of sprinkler irrigation experiments were conducted to determine the influences of water application rate (WAR), pre-irrigation substrate water content (PSWC), and cyclic irrigation on water and N leaching from container-grown plants. Prior to experiments, Marigold (Tagetes erecta L. ‘Apollo’), were glass house-grown in pine bark-filled 3.8 liter (1 gal) containers. Prior to treatment, substrate was dried via evapotranspiration (ET) to targeted PSWCs. A simulated overhead irrigation system applied the daily water allotment in a single continuous application or cyclically (multiple applications); in most cases the respective ET volumes were applied to the substrate. Water application efficiency (WAE; water vol retained in substrate + water vol applied to substrate) was determined, and in some experiments, leachates were analyzed for EC, NO3-N and NH4-N. A negative linear relationship existed between WAR and WAE. Leachate NO3-N and NH4-N concentrations were unaffected by WAR, however, total N leached increased with increasing WAR. WAE of cyclic irrigation was 4% higher (absolute basis) than with continuous irrigation; WAE increased as the time interval between cyclic applications increased from 20 to 60 min. Regardless of how water was applied, WAE was inversely related to PSWC and application volume. These experiments showed that the most effective method to increase WAE is to irrigate at relatively low PSWCs; if irrigation occurs at relatively high PSWCs, then relatively low volumes should be applied.

scholarly journals Centre-pivot irrigation system design for uniform water application rate

2020 ◽  
Author(s):  
Giorgio Baiamonte ◽  
Mustafa Elfahl ◽  
Giuseppe Provenzano
Keyword(s):  
System Design ◽  
Irrigation System ◽  
Design Procedure ◽  
Application Rate ◽  
Water Application ◽  
Irrigation Systems ◽  
Flow Rates ◽  
Irrigated Area ◽  
Application Rates ◽  
Irrigation System Design

<p>In the last few decades, the use of centre-pivot irrigation systems has significantly increased, since it makes farming easier, is more efficient and less time-consuming compared to the other irrigation systems. Several studies have been focused on the hydraulics of the centre-pivot systems. Standard high-pressure impact sprinklers or low-pressure spray sprinklers or Low Energy Precision Application (LEPA) systems are generally mounted on the pipeline.</p><p>To ensure the uniformity of water application, the centre-pivot design requires increasing the flow rates along the lateral, because the sprinklers farther from the pivot move faster, and therefore their instantaneous application rates must be greater. Thus, the irrigated area under a centre-pivot system expands substantially with increasing system length. To irrigate the increased area by maintaining constant the application intensity, the manufacturers propose: i) to increase the flow rates of equally spaced sprinklers, ii) to gradually decrease the spacing of equal-flow sprinklers along the centre-pivot lateral, and iii) to use semi-uniform spacing, which is a combination of the first two methods.</p><p>However, the most common centre-pivot systems have equally spaced sprinklers with increasing flow rates (nozzle sizes) along the lateral, which is probably the easiest method from a practical point of view. Although many definitions and design procedures can be found in the technical literature, a universally accepted design procedure has not yet been found. In fact, the issue of centre-pivot irrigation system design is widely debated and there is still a need for simple, yet adaptive designing guidelines for farmers using these systems, specifically to maximize water use efficiency.</p><p>This study presents an alternative design procedure of centre-pivot irrigation system allowing to set favourable water application rates. First, the sprinklers’ spacing distribution corresponding to a fixed irrigated area along the radial direction is derived. According to this outcome, the results showed that sprinkler characteristics and/or pipe diameter need to be varied along the lateral, based on the desired and uniform water application rate. Then, for a practical case, an application based on the proposed hydraulic design procedure was performed and discussed.</p>

scholarly journals Cold Protection of Leatherleaf Fern in Shadehouses Using Water and Crop Covers

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 808A-808
Author(s):  
Robert H. Stamps
Keyword(s):  
Irrigation System ◽  
Application Rate ◽  
Water Application ◽  
Crop Water ◽  
Irrigation Systems ◽  
Application Rates ◽  
Weight One ◽  
Frost Protection ◽  
Rumohra Adiantiformis ◽  
Supply Water

Six shadehouses were used in tests of irrigation rates and crop covers for cold-protecting leatherleaf fern [Rumohra adiantiformis (Forst) Ching]. Each shadehouse was equipped with two irrigation systems—one over-the-crop to supply heat and one over-the-shadehouse to supply water for sealing the openings in the shade fabric with ice. The over-the-crop irrigation system consisted of frost protection wedge-drive impact sprinklers providing water application rates of 0.30, 0.56, and 0.76 cm/h. Six-m × 9-m spunbonded polypropylene crop covers weighing 20 and 51 g·m–2 were tested. During radiation freezes, all water application rates protected immature fronds from damage. Damage during advective freezes decreased with increasing water application rate, but, even when crop covers were used in conjunction with irrigation, some damage still occurred. Temperatures under the lighter-weight cover were higher than under the heavier-weight one, probably because more water passed through the lighter cover to the crop. Water application rates had no effect on frond yield.

scholarly journals Soil Water Infiltration Model for Sprinkler Irrigation Control Strategy: A Case for Tea Plantation in Yangtze River Region

Agriculture ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 206
Author(s):  
Lu ◽  
Liu ◽  
Montazar ◽  
Paw U ◽  
Hu
Keyword(s):  
Soil Water ◽  
Sprinkler Irrigation ◽  
Application Rate ◽  
Water Infiltration ◽  
Water Application ◽  
Slope Gradient ◽  
Infiltration Depth ◽  
Infiltration Model ◽  
Soil Water Infiltration ◽  
River Region

The sprinkler irrigation method is widely applied in tea farms in the Yangtze River region, China, which is the most famous tea production area. Knowledge of the optimal irrigation time for the sprinkler irrigation system is vital for making the soil moisture range consistent with the root boundary to attain higher yield and water use efficiency. In this study, we investigated the characteristics of soil water infiltration and redistribution under the irrigation water applications rates of 4 mm/h, 6 mm/h, and 8 mm/h, and the slope gradients of 0°, 5°, and 15°. A new soil water infiltration model was established based on water application rate and slope gradient. Infiltration experimental results showed that soil water infiltration rate increased with the application rate when the slope gradient remained constant. Meanwhile, it decreased with the increase in slope gradient at a constant water application rate. In the process of water redistribution, the increment of volumetric water content (VWC) increased at a depth of 10 cm as the water application rate increased, which affected the ultimate infiltration depth. When the slope gradient was constant, a lower water application rate extended the irrigation time, but increased the ultimate infiltration depth. At a constant water application rate, the infiltration depth increased with the increase in slope gradient. As the results showed in the infiltration model validation experiments, the infiltration depths measured were 38.8 cm and 41.1 cm. The relative errors between measured infiltration depth and expected value were 3.1% and 2.7%, respectively, which met the requirement of the soil moisture range consistent with the root boundary. Therefore, this model could be used to determine the optimal irrigation time for developing a sprinkler irrigation control strategy for tea fields in the Yangtze River region.

Effect of sprinkler irrigation system on air temperatures and use of chemicals to protect cherry and peach trees from early spring frost

2006 ◽  
Vol 46 (5) ◽  
pp. 697 ◽  
Author(s):  
C. Tsipouridis ◽  
T. Thomidis ◽  
I. Xatzicharisis
Keyword(s):  
Gibberellic Acid ◽  
Irrigation System ◽  
Sprinkler Irrigation ◽  
Early Spring ◽  
Copper Hydroxide ◽  
Chlormequat Chloride ◽  
Spring Frost ◽  
Air Temperatures ◽  
Frost Protection ◽  
Peach Trees

The use of some chemicals including vitamins C and E, copper hydroxide, gibberellic acid, pinolene, urea, captan, ethephon, chlormequat chloride and paclobutrazol for early spring frost protection of cherry and peach trees was studied. Applications before frost of urea, copper hydroxide and a mix of glycerine or captan + vitamins C and E reduced the damage to flowers (at rates up to 40–60%), while application of gibberellic acid in combination with captan and pinoline 6 h after frost, reduced the damage by 40–50%. Ethephon delayed the bloom time of peach and cherry trees for about a week. Placing 2 sprinkler heads (200 L/h) on the tree at 40 or 280 cm height raised the temperatures 2.0 and 1.0–1.5°C, respectively.

Growth and yield of rice under sprinkler irrigation on a free-draining soil

1985 ◽  
Vol 25 (3) ◽  
pp. 636 ◽  
Author(s):  
J Blackwell ◽  
WS Meyer ◽  
RCG Smith
Keyword(s):  
Irrigation System ◽  
New South ◽  
Sprinkler Irrigation ◽  
Sprinkler System ◽  
Growth And Yield ◽  
Pan Evaporation ◽  
Water Application ◽  
Class A ◽  
South Wales ◽  
Class A Pan

A line-source sprinkler irrigation system was used to study rice growth under irrigation on a free-draining soil in the Murrumbidgee Irrigation Area of New South Wales. Ponded rice was grown on the same soil for comparison. Seven levels of sprinkler water application were examined, ranging from 26 to128% of Class 'A' pan evaporation. Apparent efficiency of water use ranged from 3.4 kg of grain/mm for the highest yielding sprinkler treatment to 1.85 kg of grain/mm for the highest yielding ponded treatment. Excellent weed control was achieved by herbicides applied through a sprinkler system.

scholarly journals Effects of Travel Speed and Collector on Evaluation of the Water Application Uniformity of a Center Pivot Irrigation System

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1916 ◽  
Author(s):  
Yongchong Li ◽  
Xin Hui ◽  
Haijun Yan ◽  
Diyi Chen
Keyword(s):  
Cross Section ◽  
Irrigation System ◽  
Weighted Average ◽  
Travel Speed ◽  
Application Rate ◽  
Water Application ◽  
Center Pivot ◽  
Average Water ◽  
Coefficient Of Uniformity ◽  
Selection Of

Water application uniformity is an important performance parameter when designing and operating an irrigation system. Performance tests of a center pivot irrigation system equipped with fixed and rotated spray plate sprinklers (FSPS and RSPS, respectively) were conducted at five travel speeds. The effects of travel speed, collector size, and setting height on water application uniformity were evaluated using Heermann and Hein’s coefficient of uniformity (CUH). The CUH was 12.7% higher for the RSPS than the FSPS and decreased as the travel speed increased. Collector size and setting height affected CUH, and CUH was higher when the collector had a large opening cross-section compared to the collector with a small opening cross-section. CUH was higher when the collector with a low setting height compared to when it a high setting height for the FSPS. However, collector setting height had no effect on CUH for the RSPS. The weighted average water application depth (Dw) decreased as the travel speed increased. Collector size had no significant effect on Dw, but Dw with a low collector setting height was larger than the values with a high collector setting height. The water application rate increased as distance from the pivot point increased and was higher for the FSPS than the RSPS. The results will improve the selection of travel speed and collector when the water application uniformity of a center pivot irrigation system is evaluated.

scholarly journals Capillary Mats for Maintenance of Plants in the Retail Nursery

2008 ◽  
Vol 18 (2) ◽  
pp. 250-255 ◽  
Author(s):  
Ursula K. Schuch ◽  
Jack J. Kelly ◽  
Trent Teegerstrom
Keyword(s):  
Irrigation System ◽  
Sprinkler Irrigation ◽  
Cost Effective ◽  
Well Water ◽  
Water Application ◽  
Overhead Irrigation ◽  
Effective System ◽  
Set Up ◽  
True Alternative ◽  
Overhead Sprinkler

Capillary mats and overhead sprinkler irrigation were used in a simulated retail environment to maintain annual and perennial plants in containers for various time periods during summer and winter. Combining the results from both seasons, four species with dense canopies had larger canopy sizes when maintained on the capillary mats, three species requiring more drainage had larger canopies with overhead irrigation, and five species were unaffected by irrigation systems. Substrate electrical conductivity was higher for some species in winter for plants on capillary mats, conserving fertilizer compared with overhead irrigation. Most species tolerated either irrigation system well. Water application was 71% less in summer and 62% less in winter to maintain plants on capillary mats compared with overhead irrigation. An economic analysis compared the investment required for setup and maintenance of plants in a retail situation using hand watering, overhead sprinkler, or capillary mat irrigation. The partial budget indicates that capillary mats are a labor-saving alternative to hand watering in a retail nursery and will compensate for the higher initial investment within less than 1 year. The overhead sprinklers are the most cost-effective system of the three because of less costly initial set-up and maintenance than the capillary mats; however, they are not a true alternative to hand watering in a retail situation because they interfere with customer traffic and worker activities.

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