Study on the optimal water content for blueberries
To optimize the irrigation strategy, producers must have a clear understanding of the humidity, drainage and EC levels. Today we will talk about the optimal conditions we want to reach.
“Maintaining optimal moisture conditions for crops growing in substrate requires a clear understanding of substrate characteristics, plant physiology and water uptake,” explains Ziv Omer, DrainVision Product Manager and agronomist at Paskal.
DrainVision, Paskal's wireless irrigation monitoring system, provides a deeper insight into drainage performance and water availability, saving water and fertilizers while improving quality and quantity of yield.
Differences between crops
“The production in different substrates with a limited volume, with different physical and chemical characteristics and water retention capacity; differences between crops and rapid depletion of water and nutrients can cause plant stress,” Ziv explains.
Therefore, in order to obtain an optimal water content in the substrate, an accurate and in-line monitoring of the water content is required.
“The most widely used irrigation controllers in greenhouses are based on the measurement of radiation, since it provides a good estimate of transpiration. However, this practice may be too limited, since there are more factors that affect plant transpiration, such as: humidity, temperature, greenhouse cover, plant variety, crop age, type of substrate, and more." .
Irrigation at fixed intervals is also a common practice, but requires additional attention, as drainage samples should be taken several times a day.
Close to the target
In some cases, the daily percentage of accumulated drainage is close to the target level, but with DrainVision the amount of drainage, time, uniformity and EC can be monitored more accurately throughout the day.
“For example, if the timing of irrigation is not precise, excessive drainage can occur in the morning or afternoon, causing a lack of drainage during the middle of the day when transpiration is at its peak, causing fluctuations in the water content and the EC level of the substrate”, explains Ziv.
Cranberry case study
For optimal production of blueberries with high yield and quality fruits, precise irrigation management is required.
“Water stress at critical moments in the development of the blueberry plant can drastically affect the yield and quality of the fruit. However, blueberry plants under water stress may not show visual signs of stress. Careful irrigation management is a key factor in achieving good yields and good plant development, and is also important for long-term plant health. On the other hand, excess watering reduces blueberry root activity, increases nutrient leaching and causes diseases such as Phytophthora”, warn.
"Implementing DrainVision in blueberry crops allows growers to provide the optimal water content throughout the day, as well as save costs on water and fertilizer."
The following graphs represent the irrigation strategy in a blueberry plantation under meshes. In this case, the producer defined two irrigation programs for the day;
- Shorter irrigation cycles and shorter intervals from morning until early afternoon.
- Longer irrigation cycles with longer intervals in the evening
Program 1- Irrigation began at 8:00 am, when the water content was approximately 1.500 g below the capacity of the field (55.136 g). The maximum capacity was reached at 9:15 am, and from that moment, and with a stable water content, it remained until 2:00 pm
To provide a constant availability of water, when the transpiration rate is high, short irrigation cycles were programmed with short intervals between cycles. The drainage performance was uniform during the irrigation period, which allowed for constant leaching and mineral runoff.
Program 2: started at 2:00 pm, characterized by a greater volume of irrigation with longer intervals between cycles.
As seen in the graph, the water content peaked at 2:00 pm, indicating a short interval before the first long watering. Since the irrigation cycles in program 2 had a volume of 610 ml, with a drain target of 30%, the first cycle should have started 430 grams below the capacity and weight of 54.706 grams (2:55 pm ). Subsequently, the lower water content that was maintained during that period also helped promote root development, prevented diseases, improved plant resistance to pathogens and allowed mineral runoff.
Guy Tamir, Agricultural Research and Development, Central Mountain Region, Israel, says that by using DrainVision, they now have the ability to adjust the watering practice of blueberry plants based on water uptake, determining the amount of leaching required . "In the near future we will also begin to compare the rate of plant growth between different irrigation practices following the DrainVision data."
New features of Drainvision
DrainVision can be synchronized with other main irrigation systems that will allow irrigation to be automatic. There are alerts available in the application that will notify the producer when any of the measured parameters cross the defined thresholds.
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