Balancing the field: Controlled environment agriculture through measurement technology

Controlled Environment Agriculture (CEA) is one of the fastest growing segments in food markets around the world. As the demand for locally grown and organic products continues to rise, the demand is being met by today’s modern greenhouses, vertical and container farms. The advancements in technology and techniques available today allow growers to produce more, with greater consistency, while using less energy and resources.

Growers can use technology to create optimum growing conditions with a high degree of precision in their facilities, allowing them a wider variety of crops with dependable results. Enclosing and climate controlling a facility can allow farmers to grow a crop from seed to harvest in less time, obtain higher yields in each cycle, and have more harvest cycles per year.

Optimizing the layout of a greenhouse can provide additional capacity when compared to conventional farming. Employing vertical farming and drip irrigation techniques can easily surpass what can be grown with traditional methods, or even in a traditional greenhouse. Considering that the more common crops grown indoors are greens, vine crops, flowers and other nursery crops, the potential for layering is limited only by lighting resources, which has become substantially less expensive in recent years.

Decreased pesticide use is also an advantage to CEA agriculture, as integrated pest management is more easily implemented. This results in a cleaner environment, sustainable crop protection, and satisfying pesticide-free food demand.

Water conservation is another major benefit to CEA. By being able to control water use through either hydroponic or aeroponic methods along with simply not losing water to ground infiltration, indoor operations require significantly less fresh water to operate. In areas that are facing water shortages and restrictions, this can be a major viability factor.

Overall energy efficiency is a key component to a CEA operation. The electricity demands of a greenhouse, automated or not, are significantly higher than with conventional agriculture, as HVAC systems and lighting are an energy burden. This is where quality sensors can make the difference. Closely monitoring the conditions in the growing space can lead to energy savings and healthier crops.

Who grows with CEA?

As almost any crop can be grown indoors, and the benefits of CEA can be seen in many different markets, from flower and ornamental growing to produce production. CEA production techniques can mean the difference between 1-2 harvests per year and 4-6 harvests per year, as well as the ability to rotate harvest periods for consistent delivery. Just about every crop grown indoors can benefit from these techniques. Some of the most popular crops currently are lettuce greens, micro-greens, vine crops and flowers. Commodity crops, mushrooms and fruits are also grown in CEA operations. A big part of the decision about what to grow results from projected profitability meeting the demand at the most favorable margins.

Types of controls

Greenhouse control can range from simple and occasional measurement with manual venting to full continuous monitoring systems and automated controls. Vaisala offers a range of instruments to suit every level of control. From sophisticated continuous monitoring systems using our own data-loggers and viewLinc software to simple and accurate hand-held sensors, Vaisala instruments meet the need for reliable measurement and data.

Put simply, better climate control means improved crops. Also, having accurate and reliable measurements will lower the costs of production through efficient resource management. The measured parameters that are of most importance are humidity, temperature, carbon dioxide, weather conditions, light, nutrients and hydration. These parameters are not only measured to promote growth rates, but also to prevent crop damage that can occur at the extreme ends of these conditions.

Humidity parameter

Humidity can be the most difficult environmental factor to control in a greenhouse and is a key performance indicator. It is directly related to the temperature of the air and can change drastically with relatively small changes in temperature. For every 20-degree drop in temperature, the water-holding capacity of the air is cut in half, and the relative humidity is doubled. This is why a decrease in temperature overnight can result in high humidity and condensation. Vaisala HUMICAP® sensors can survive getting wet, and will measure accurately once they dry.

Good watering practices and proper ventilation are the best ways to control humidity within greenhouses, and having accurate humidity measurement allows farmers to make timely and informed control decisions.

Temperature parameter

Plants can survive and grow over a wide range of temperatures also, but there are optimum temperatures for each species that encourage the optimum growth rate.

Temperature regulation is done through either natural venting or through mechanical means, such as HVAC. Knowing the temperature regulation challenges of your facility is important, and it is recommended that you study or map the different areas of the growing space to identify hot or cold spots. Accurate and dependable Vaisala temperature sensors can provide these critical measurements, which will aid in crop selection and layout decisions.

CO2 parameter

The benefits of carbon dioxide supplementation on plant growth and production within the greenhouse environment have been well understood for many years, as carbon dioxide is an essential component of photosynthesis. Examples of how productivity is increased by CO2 include earlier flowering, higher fruit yields, improved stem strength and flower size. In fact, net photosynthesis can increase up to 50% as CO2 levels increase from ambient to 1,000 ppm.

One problem observed in enclosed growing operations is that the plants will consume the available CO2, creating a deficiency and limiting growth. Supplemental CO2 - either generated through combustion or supplied in gas, liquid or solid forms - is a common way to provide the crops with this critical resource. There is also a human safety concern when supplying the gas. Accurate CO2 measurements from Vaisala CARBOCAP® sensors offer control of this resource, with long-term stability and a low cost of ownership. Learn more by downloading our application note on optimizing plant growth with CO2 measurement.

Summary

The bottom line in any greenhouse or controlled environment agriculture system is determined by the efficiency and profitability of the operation:

• Precise measurement and controls produce efficient and profitable results
• Precise measurement begins with quality sensors that are accurate and dependable
• Accuracy and dependability reduce overall cost of ownership
• Quality measurement is worth the investment, because it directly affects the bottom line

Make the best out of your operation with quality measurement tools from Vaisala. For more information, please Contact us.