How Can Farmers Reduce Center Pivot Irrigation Costs by 50%
Center pivot irrigation is a common technique in farming, yet it has the highest costs. Diesel alone can cost up to $25,000 yearly for 15 acre-inches per center pivot system. Farmers have enormous pressure to reduce costs and save water, but it’s not easy without jeopardizing crop quality and yield. It requires a systematic and careful process.
This 4-step irrigation optimization approach using wireless soil moisture sensors can help farmers reduce water consumption! With a reduction of up to 50%, they can slash center pivot diesel costs by a hundred thousand USD in 20 years, with a payback in less than 2 years.
Read this blog for the four-step irrigation optimization approach – and check out the cost saving calculation example!
Typical Center Pivot Irrigation Costs
Center pivot operating costs consist of, e.g., diesel, electricity, oil and lubricants, repairs and maintenance, labor, and more. Diesel fuel is one of the primary operating costs, and it varies greatly. According to the University of Georgia’s crop production budget 2019, a center pivot irrigation system can consume diesel worth $12.50, and electricity for $7.00 per every irrigated acre-inch.
So, if 15 acre-inches are applied during a season, the total yearly diesel bill becomes $187.5 per acre. This corresponds to a total of $25,600 of yearly diesel expenditure for a fully-rotating center pivot system assuming a 136 acre field. If electricity was used, the total yearly energy cost in the same scenario would be $14,280.
Reducing the Costs via Optimized Irrigation – What are the Risks?
The center pivot operating costs are directly proportional to the utilization of the system: the number of runs and the amount of water pumped. Reducing water consumption is a challenging task, however. The lack of accurate soil moisture data has been the biggest constraint – i.e., how much water plants can get from the soil currently and how much irrigation is needed?
Optimal soil moisture is critical for plants. Recent research on soil moisture optimization showed that yield losses start to develop well before drought reaches the wilting point. Actually, plant growth slows down immediately when root-zone soil moisture falls below the optimal range.
Even a small water deficiency has several negative impacts on plants: less water reduces photosynthesis, which slows down growth. Reduced water uptake means less nutrient uptake.
So, decreasing water usage without continuous, underground soil moisture monitoring is a huge risk, because traditional above-ground weather observation appliances such as rain gauges, evaporation models, or drones do not represent underground conditions accurately.
How to Reduce Water Consumption Safely?
There is no one-size-fits-all approach to water savings because required actions depend on farm location, soil quality, overall weather conditions, crop type, and several other parameters.
However, by continuously monitoring underground soil moisture, and optimizing center pivot irrigation based on reliable feed-back, farmers can follow the best-practice methods – such as the four-step irrigation optimization approach – more accurately. This enables farmers to reduce water consumption more efficiently and with a lower risk than traditional techniques – such as manual inspection, evaporation models, or weather observations.
The Four-step Approach for Optimizing Irrigation
Here’s how to optimize center pivot irrigation based on reliable underground soil moisture data to save diesel and electricity costs, and water.
1. Obtain the Optimal Soil Moisture
Always aim to optimize and maintain your soil moisture at Field Capacity
level (FC). It is optimal for plant root health: water is readily available, and there is plenty of oxygen for transpiration. But, if plants consider FC as optimal moisture content, how much drier soil plants can tolerate? Use underground soil moisture sensors to define the lowest acceptable soil moisture level to save even more water. However, monitor soil moisture continuously to avoid too dry soil and slowed down plant growth. On the other hand, soil moisture above the FC level also hampers growth and causes water leakage.
2. React on Incidental Rainfalls Accurately
Observe how natural rainfall influences root zone moisture to know how much you can cut back on center pivot irrigation to save water. Note, that rain gauge’s information does not indicate actual underground soil moisture, and precipitation does not fall evenly nor neccessarily remain still.
3. Optimize Irrigation Based on In-field Soil Moisture Variations
Take into account in-field soil moisture variation in the center pivot runs to reduce water consumption locally. Soil moisture is never evenly distributed across a field. It can vary highly from one area to another, and you should optimize irrigation accordingly – or at least be aware of the high and low values.
4. Deploy the Controlled Deficit Irrigation strategy
Deploy the Controlled Deficit Irrigation (CDI) strategy to put just the right level of stress on plants to achieve higher crop quality and save lots of water while suffering only a tolerable yield loss.
Without continuously monitoring the actual root-zone soil moisture, this delicate balancing comes with an unacceptable risk of total crop failure.
Soil Monitoring in Center Pivot Irrigation – Is there an easy way to do it?
Running center pivot irrigation systems and managing a comprehensive underground soil moisture measurement system simultaneously in the same area is complicated with traditional solutions.
There is an easy way, now! The new wireless underground soil monitoring solution doesn’t affect center pivot operations. Farmers can simply bury wireless soil sensors in different parts of the field at different depths. The Soil Scout sensors measure underground soil moisture, temperature, and salinity, and upload the data every 20 minutes. Farmers can see the information on a smartphone or laptop continuously and in real-time.
Based on this data, farmers can follow long-term trends, compare root-zone soil moisture in different areas, and plan the center pivot irrigation runs in an optimized way – to improve productivity, reduce water consumption, and save operating costs!
The wireless soil sensors are easy to install; simply dug them into the soil. They do not have cables, so farmers can place them deep enough to stay safe from the center pivot wheels. The battery can operate up to 20 years underground; no maintenance is needed.
How to Estimate the Center Pivot Irrigation Cost Savings?
Center pivot irrigation diesel and electricity expenditure varies from one farm to another based on the amount of pumped water, water source, fuel consumption, the price of diesel per liter, cost of electricity per kWh, and many, many other reasons. However, based on rule-of-thumb assumptions, savings of up to 50% can be achieved as per the diagram below.
The irrigation optimization guide explains more about how to estimate water savings. With the below calculation model, you can estimate the potential cost savings in a specific scenario.
What’s the payback time for the Soil Scout wireless underground soil monitoring solution?