Optimizing Irrigation

Irrigation monitoring systems save water and dollars

Credit: ISTOCK/RAPIDEYE

Commercial growers, property managers, and landscapers can attest to how sophisticated and beneficial irrigation monitoring has become in terms of optimizing water consumption and plant growth, and maximizing operational profitability. Two examples from California—where much of the nation’s food supply is produced but where water availability remains a critical public policy issue—illustrate how irrigation monitoring and control systems can serve as a valuable business tool.

Larry Peltzer, a fourth-generation citrus grower and owner of LRP Orange Co. in Visalia, CA, reduced watering time and frequency and improved water efficiency by up to 40% by using wireless irrigation monitoring stations that collect real-time soil moisture data. The company monitors soil moisture trends through the profile on iPads and mobile phones and decided to extend its irrigation cycle to every 12–15 days, as opposed to every seven to nine days. According to Peltzer, extending the cycle allowed LRP to reduce water use by 30–40%.

Peltzer explains that the need for irrigation monitoring arose from a lack of available surface water and depletion of LRP’s underground water supply. Due to those challenges, the company focused on ensuring maximum efficiency in terms of irrigation timing and water volume application. Peltzer adopted Rain Bird’s ClimateMinder system, which was installed and maintained by Irrigation Matters of Tulare, CA. He says that the system has allowed LRP to irrigate less by eliminating guesswork. By using the system, LRP has become more efficient with its water usage and fertilizer application and has also saved on fuel and labor, reports Peltzer. The efficiency increase was clearly due to Irrigation Matters’ interpretation of the ClimateMinder system data and work with the grower to make operational adjustments.

Additionally, LRP increased its crop yield by 15–20% due, in part, to the use of the system. The yield increased to 60-plus bins per acre in 2014, compared with 50-plus bins per acre the previous year. Peltzer and LRP found that the system made the yield increase possible by helping the company reduce the risk of root disease development that otherwise would occur from excessive soil moisture levels. Also, avoiding overwatering ensures that applied nutrients stay in the root zone.

Like many growers, LRP also uses the system to continuously monitor the changes in electrical conductivity (EC) to make sure they are not pushing their fertilizers below the root zone. By taking bulk and pore EC measurements, the company can tell the distance that liquid fertilizer penetrates when it fertigates. Now, LRP is able to keep fertilizer in the root zone. Pointing out that the state is watching nitrate applications closely, Peltzer notes that the company will have evidence to show that it is not abusing its nitrogen applications.

A historic drought in the western United States promises to challenge Peltzer and LRP for at least the next few years. Given the lack of surface water, he acknowledged that his company needs to manage available water as efficiently as possible. One of his ranches has no wells and LRP is allocated only 90 days of surface water. As a result, the company is harvesting its Valencia oranges to take the load off the trees so that they can survive the drought. Use of irrigation monitoring is critical to the survival of operations like LRP.

The need to optimize water use is not confined to produce growers such as Larry Peltzer. Commercial landscapers tasked with keeping building grounds looking green and vibrant need to do so without excessive water consumption. In 2012, Dennis Bryan, president of Water Savers, a water-auditing and consultation company in central California, got a call from a property management company in central California that was struggling to achieve such a balance.

One of the company’s properties was using an excessive volume of irrigation water to maintain vibrant greenery. The appearance of the property was critical to the property owner, but the property manager was getting socked with water bills totaling thousands of dollars every month. A particularly problematic aspect of the billing was that the water rates were graduated, so the rate escalated as consumption increased. The property manager knew that something needed to be done, and fast. He reached out to Water Savers to see if the company could suggest a way to correct the situation.

After completing a site survey, Bryan came up with a solution: deploy a closed-loop irrigation system utilizing Acclima soil moisture sensors and controllers. This system would give the lawn precisely the amount of water needed. Bryan had installed similar systems on other properties and obtained significant savings for the property owners.

At this site, Water Savers installed five controllers and one or two sensors per controller. The system yielded an economic benefit in the first month, one that surprised Bryan, who has a great deal of experience with such systems. Within the first month of installation, the system yielded a savings of 85% compared with the same month the previous year. Further, after 10 months of system utilization, the average savings were about 40–50%. A supplementary benefit of installing the system was that it allowed Water Savers to identify weak points in the system, i.e., weak sprinkler heads. The company replaced those sprinkler heads with units that provided more even distribution of water over the property, contributing to the savings.

Acclima’s closed-loop irrigation system uses data collected by the sensors to set the optimal moisture threshold. The controller applies water if the moisture reading is lower than the threshold. Below: Acclima’s SDI-12 Digital TDT soil moisture sensor

Acclima’s closed-loop irrigation system uses data collected by the sensors to set the optimal. moisture threshold. The controller applies water. if the moisture reading is lower than the threshold.

Optimization Relies on Soil Moisture Sensors
Ultimately, irrigation monitoring systems are all about receiving optimal outputs (plant growth, operational profitability) from optimal inputs (water and fertilizer). More and more users are becoming aware that the Law of Diminishing Returns applies to the application of these inputs after a certain threshold. Monitoring systems serve the valuable role of identifying where optimal input thresholds exist. Finding that threshold and adjusting inputs accordingly results in successful growing and resource management—the latter is increasingly critical as some inputs become more scarce and regulations governing their use grow stricter in many parts of the country.

The idea of actually reducing inputs and getting healthier plants does take some getting used to, according to Acclima’s founder and chairman, Scott Anderson. He notes that many of his customers reap the benefits of water and financial savings by using his irrigation monitoring systems and certainly appreciate them. But, says Anderson, many customers are surprised to see that their lawns and plants become healthier, and greener. Acclima helps these customers to understand that less water allows plants’ roots receive more oxygen and nutrients, the latter of which do not get washed away into the subsoil.

True irrigation monitoring that allows optimization of inputs based on soil moisture content rather than programmed watering times relies on the use of a critical component of a monitoring system: the soil moisture sensor. This unit signals an irrigation controller when to water plants via sprinklers, drip irrigation tubing, and the like. Increasingly, wireless telemetry stations tie together systems on multiple sites, giving irrigation managers the ability to monitor the sites from a central location.

In late 2012, Rain Bird acquired the ClimateMinder system, which consists of …

Water Efficiency May 2016To continue reading the full article check out the May edition of Water Efficiency, please click here. You may need to log-in or subscribe to our magazine.

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