Irrigation Control of Container Crops by Means of Tensiometers (original) (raw)
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Scheduling Irrigation Using Automatic Tensiometers for Pea Crop
2018
Recent technological advances have made soil water sensors available for efficient and automatic operation of irrigation systems. Automatic soil water sensor-based irrigation seeks to maintain a desired soil water range in the root zone that is optimal for plant growth. Automatic tensiometers were buried at 30 cm depth under the sandy soil surface of Nubaria experimental station of NRC, subjected to drip irrigation system to automatically schedule irrigation for pea crop. Soil moisture potentials 70, 75 and 85 kPa, represented 3 irrigation treatments and 3 Potassium treatments 50, 75 and 100% of 100 kg fed. -1 , the officially recommended amount of Potassium fertilization for a pea crop by the ministry of agriculture in Egypt for sandy soils, were scheduled and added with the drip irrigation portions. The obtained results revealed that using soil moisture potentials 70, 75 and 85 kPa were equivalent to 85, 75 and 60% of the field capacity of the soil, respectively. The average crop...
Journal of Horticulture and Forestry, 2011
In upland areas of Northern Thailand, lychee (Litchi chinensis, Sonn.) is one of the predominant fruit crops. Fruit development takes place during the dry season (January until June). Therefore, high lychee yields can only be obtained under irrigation. As water is an increasingly scarce resource in the hillsides, strategies for more efficient water use are fundamental for a sustainable increase in agricultural production. An Automatic Tensio Control (ATC) unit was developed to use soil matric potential to open and close the inlet valve of a micro-irrigation lateral. In order to test the functioning of the ATC in the field, four different irrigation regimes have been tested in cooperation with local farmers on 10 year old lychee trees on a commercial orchard in Mae Sa Mai, close to Chiang Mai, Thailand. Testing the ATC on station and under field conditions, it has proven its reliability in maintaining a favorable moisture regime in the soil. The irrigated lychee trees responded to ATC irrigation with a higher yield and higher fruit weight compared to the other treatments. ATC works without electric components, so that it can be operated in areas without electricity. Furthermore, it is assembled from cheap and simple materials. Thus, it can be easily copied and adapted to different agro-ecological and socioeconomic environments.
Agriculture and Agricultural Science Procedia, 2015
Irrigation is a crucial practice that operators often perform empirically, relying on their own experience, especially in productive areas characterized by low technology agriculture (i.e. several parts of Mediterranean countries). One of the possible approach for proper irrigation scheduling is measuring the soil water potential, simple and easy to manage. The purpose of this research was to examine the effects of two different irrigation regimes (obtained by the use of tensiometers connected to a relay controller) on yield, fruit quality and water consumption of greenhouse tomato (Solanum lycopersicum L. cv Naxos) and cucumber (Cucumis sativus L., cv Sarig, in the first cropping cycle, and the local landrace 'Mezzo lungo di Polignano', in the second one) grown on a silty-clay soil in Mediterranean conditions. For each species, two tests (August-February and February-July cycle) were carried out in a plastic greenhouse-tunnel. Drip irrigation was adopted, with automated schedule based on tensiometer readings. Two water potential irrigation set-points were compared: -100 and -400 hPa for tomato and -100 and -300 hPa for cucumber, in both cycles. Yield (marketable and unmarketable) and quality traits of fruits (soluble solids, dry matter and titratable acidity) were determined. Water consumption was calculated at the end of each crop cycle. In the first cycle, the two water regimes did not affect the yield of tomato and cucumber. The cucumber irrigated at the lowest soil water potential set-point produced fruits with 8% higher dry matter. In the second cycle, the tomato irrigated at the potential of -400 hPa showed a 40% lower yield (mainly due to the lower fruit size) compared to that of plants irrigated at -100 hPa. However, the fruits of tomato plants irrigated at -400 hPa showed total soluble solids, dry matter and titratable acidity, respectively 41, 45 and 59% higher than plants irrigated at -100 hPa. In both crop cycles, a water saving of 35% and 46%, on average, for tomato and cucumber, respectively, was obtained using the lowest potential as irrigation set-point. Proper use of tensiometer could allow a better use of water resource. Selection of proper water potential set-points according to the cultivation season is crucial for satisfactory results. The positive effects of a controlled and moderate water stress on fruit quality should be taken into account.
Journal of Agricultural Science and Technology B
Water is scarce in Palestine and water saving is becoming very important issue. Water management is one of the promising solutions to save water. The purpose of this work was to study the effect of two types of irrigation regimes on water consumption, yield and growth parameters of cucumber (Cucumis sativus L.) under open field conditions. Cucumbers were grown on a silty-clay soil in Palestinian local conditions. The irrigation regimes used were farmer based irrigation (FI) and tensiometer based irrigation (TI). The results showed that there were no significant difference in crop yield between FI (3.5 kg/plant) and TI (3.4 kg/plant). Dry matter was 14.7% less in TI treatment than that in FI treatment, while water saving was 35.7% in TI treatment. Thus, proper use of tensiometer could be utilized for a better use and management of water resource. Selection of proper water potential set-points according to the cultivation season is crucial for satisfactory results.
Problem statement: In irrigation water management, irrigation water use represents a substantial opportunity for agriculture water savings. Automation of irrigation systems, based on Soil Moisture Sensors Systems (SMSS) has the potential to provide maximum water use efficiency by maintaining soil moisture at optimum levels. Approach: The objective of this research was to evaluate the performance of soil moisture sensors under field conditions during growing season in two different irrigated. This evaluation to be conducted with regard to accuracy; precision; quickness of the response to moisture variation. Moreover to quantify the easiness of use, this encompasses installing and operating the instrument as well as interpreting the readings. Results: The Watermark resulted in higher tension readings than the tensiometers. While Watermark showed a consistent and increasingly drier estimate of water content compared to tensiometers. However, the trend of soil water tension curves that resulted from both treatments was very similar. The linear relationships of the Soil Moisture Content (SMC) obtained from all sensors and gravimetric measurement were observed to be best fit. The correlations (R 2 ) are ranging from 0.96-0.98 and from 0.91-0.95 for tensiometers and watermarks successively. The statistical analyses indicate that changeability existed between soil water contents by the sensors and the gravimetric method. Conclusion: Soil Moisture Sensors Systems (SMSS) can be used: To monitor soil moisture sensors under wheat crop cultivation practices using intelligent irrigation system. The tensiometers and Watermarks were less responsive to the soil drying between irrigations than GM. So, Watermark can operate in a drier range than tensiometers, but with a lower resolution at the wet end of soil water tension. Anyhow, watermark remains a good tool for automatic irrigation scheduling and be integrated with inelegant irrigation systems even the noted drawbacks.
Automatic controller to water plants
Scientia Agricola, 2010
Despite the massive demand of water for plant irrigation, there are few devices being used in the automation of this process in agriculture. This work evaluates a simple controller to water plants automatically that can be set up with low cost commercial materials, which are large-scale produced. This controller is composed by a ceramic capsule used in common domestic water filters; a plastic tube around 1.5 m long, and a pressostate used in domestic washing machines. The capsule and the pressostate are connected through the tube so that all parts are filled with water. The ceramic capsule is the sensor of the controller and has to be placed into the plant substrate. The pressostate has to be placed below the sensor and the lower it is, the higher is the water tension to start the irrigation, since the lower is the pressostate the higher is the water column above it and, therefore, the higher is the tension inside the ceramic cup to pull up the water column. The controller was evaluated in the control of drip irrigation for small containers filled with commercial organic substrate or soil. Linear regressions explained the relationship between the position of pressostate and the maximum water tension in the commercial substrate (p < 0.0054) and soil (p < 0.0001). Among the positions of the pressostate from 0.30 to 0.90 m below the sensor, the water tension changed from 1 to 8 kPa for commercial substrate and 4 to 13 kPa for the soil. This simple controller can be useful to grow plants, applying water automatically in function of the water tension of the plant substrate.
MCAST Journal of Applied Research & Practice
The Maltese islands face challenges of water scarcity owing to a lack of rainfall and limited water resources (RDP 2021). The main sources of water for agriculture in Malta come from the mean sea-level aquifer, the perched aquifer, rainwater harvesting, and treated sewage effluent. However, most of these are dependent on precipitation which is another problem in itself due to the scarcity of rainfall in more recent years. Although soil tensiometers have been in use in agriculture for decades, in Malta there is no evidence of their use. Research was done on the potato crop variety Cara which was divided into two groups: the control which was irrigated by observation of the crop and soil, and the experimental group which was irrigated using soil tensiometers. The irrigation volume was recorded for each group and, during harvesting, the weight and number of tubers were recorded. This experiment demonstrated that the water use efficiency can be improved with the use of soil tensiometers...
Software for the automatic control of irrigation using weighing-drainage lysimeters
Agricultural Water Management, 2015
Among all the existing methods to study crop water requirements, necessary for an efficient irrigation management, the most accurate is the one based on the use of weighing lysimeters. The best known lysimeters are those used for crops in bare soil, with similar dimensions to the plantation frame of the measured species. These lysimeters are buried in the ground, require civil works, have a high cost and are commonly used in experimental plots to determine crop coefficients. There are cheaper and smaller scale lysimeters used to monitor water balance in pots without civil works. Although crop coefficients obtained from these lysimeters are not comparable to those obtained from crops in the ground, they may be useful to accurately determine the plants water needs so they can be used as a reference to irrigate the rest of potted plants of the plot. The objective of this work was to develop and evaluate a software system to optimize irrigation using weighing lysimeters in a potted crop. The software was programmed in a compact embedded controller using the LabVIEW graphical programming language with the Real-Time module. This controller receives data from the lysimeters throughout a Modbus/RS-485 communication network, processes them and realizes the calculations to control the irrigation valves in real time. The system was tested in an experimental plot owned by the "Escuela Politécnica Superior de Orihuela" with Vitis Vinifera L. cv Bobal. The software allowed the acquisition and data logging as well as irrigation scheduling based on water balance obtained from weighing lysimeters i.e. based exclusively on actual crop water needs.
Agricultural Water Management, 2015
This research aims at testing an automatic control irrigation system, using a wireless sensor network, in traditional Galician vineyards of Vitis vinifera (L.) cv. 'Godello' and cv. 'Mencía' to determine the threshold values of soil water potential at which plant stress begins, calibrating crop coefficients, building soil-water characteristics curves and measuring plant water status. In the cv. 'Godello' trial, rain-fed and two irrigations systems (surface and subsurface drip irrigation) were conducted over two growing seasons (2012-2013); during the same seasons cv 'Mencía' was also studied, but only under rain-fed conditions. The SIMDualKc model, which estimates soil water balance by means of the dual K c approach, was used to estimate crop evapotranspiration (ET c) by calibrating the full basal crop coefficient for the vine and cover crop (K cb full), which represents the transpiration component of ET c , and a soil evaporation coefficient (K e). The model was calibrated and validated by comparing model simulations with TDR observed soil water content data. Granular matrix sensor (GMS) was linked in a wireless sensor network; soil water potential measured with GMS, was used to correlate with TDR data. Leaf water potentials (LWP)-midday and stem-allowed us to obtain plant water status. A good fit was obtained between SIMDualKc model and TDR (r 2 > 0.74), TDR and LWP (r 2 > 0.65), TDR and GMS (r 2 > 0.81), showing that continuous measures with GMS permit establishing a threshold value related with leaf water potential (midday or stem). For both cultivars, the threshold was « soil = −0.1 MPa. The process applied in this study proved to be useful for managing water in real-time in a vineyard; triggering the irrigation system when the threshold value was reached.