Soil sensors and CO₂ sensors contribute to achieving sustainable development goals

Soil sensors assist in detecting soil salinity damage 

Climate change caused by global warming has led to rising temperatures and sea levels, resulting in increased droughts and heavy rainfall-related damage worldwide. Oceans and land across the globe are suffering from various adverse effects. Among these, the negative impact on farmland soil - such as stunted plant growth - poses severe threats to food supply stability. To achieve sustainable agriculture, prompt measures must be taken to address affected soil. 

Currently, water damage from heavy rainfall is often linked to global warming. Conversely, some regions are experiencing reduced rainfall due to climate change, leading to soil salinity accumulation and crop damage. In arid areas, the amount of groundwater rising to the surface and evaporating exceeds rainfall. As a result, salts from groundwater accumulate near the surface (salt accumulation), which can cause crop damage. Improper irrigation can also contribute to soil salinity. Additionally, seawater inundation from tsunamis is another cause of increased soil salinity. 

The primary effects of salinity damage on crops include: 

1. Osmotic Stress: High salt concentration in the soil solution makes it difficult for plants to absorb water, leading to water deficiency even when soil moisture is adequate. This reduces overall plant growth and causes wilting.
2. Ion Toxicity: Excessive sodium (Na⁺) and chloride (Cl⁻) ions can accumulate in plant tissues, becoming toxic and disrupting cellular functions. This can damage roots and leaves, causing leaf burn, necrosis, and premature leaf drop.
3. Nutrient Imbalance: Salts interfere with the uptake of essential nutrients such as potassium, calcium, and magnesium. This imbalance can weaken plants, reduce photosynthesis, and impair metabolic processes.
4. Reduced Germination and Seedling Growth: High salinity can inhibit seed germination and slow down seedling development, leading to poor crop establishment.
5. Lowered Yield and Quality: Salt stress often results in stunted growth, fewer flowers and fruits, and overall lower crop yields. The quality of produce may also decline due to physiological stress.
6. Soil Structure Degradation: Salt accumulation can deteriorate soil structure by causing soil particles to disperse, reducing aeration and water infiltration, which further stresses plants.

To monitor temporal changes in farmland salinity, soil sensors can be deployed. By embedding soil sensors in fields and using wireless communication, data can be continuously collected throughout the growing season. These sensors simultaneously measure ground temperature, EC (electrical conductivity), and temperature. Since higher salt content increases electrical conductivity, the EC value serves as an indicator of salinity levels, enabling ongoing observation of changes. 

High-quality soil sensors enable soil condition visualization 

Soil sensors are designed for continuous monitoring and visualization of soil and water conditions in agriculture. Murata's soil sensors integrate three sensors into a single package, allowing simultaneous measurement of EC (electrical conductivity), moisture (volumetric water content, VWC), and temperature in soil or water. The proprietary 9-electrode EC sensor employs multiple measurement modes and unique algorithms to eliminate soil-related uncertainties. 

Murata's soil sensors feature a 9-electrode EC sensor with proprietary algorithms, enabling precise measurement of pore water conductivity and fertilizer levels. EC measurements are influenced by soil properties, air, moisture, and ions, but Murata's EC sensor mitigates these uncertainties through versatile measurement modes and adjustable resistance ranges (cell constants). The high-precision moisture sensor compensates for temperature dependence and suppresses ion interference. With an IP68-rated robust structure and corrosion-resistant design, the sensor withstands harsh outdoor environments. Its proprietary technology also supports measurements in artificial growth media like rock wool and cocopeat. 

Murata's soil sensors utilize unique algorithms to measure fertilizer content exclusively. Soil consists of three components: soil particles, air, and pore water. Traditional sensors with fewer electrodes often struggle with accuracy due to moisture interference. However, Murata's sensors employ specialized algorithms to isolate fertilizer measurements, preventing over-fertilization and soil/water pollution from excessive chemical use. 

The sensors also incorporate high-precision moisture sensors that correct temperature dependence and minimize ion interference. Automated irrigation and fertilization systems often face temperature-related challenges, and dielectric-based sensors can be affected by ion-induced permittivity changes. Murata's proprietary algorithms and high-frequency measurements effectively counteract these issues. 

Murata's soil sensors offer simple yet versatile interfaces, integrating EC, moisture, and temperature sensors into a compact design. The product lineup includes five series: RS232E (SLT5005), UART (SLT5006), RS485 (SLT5007), SDI-12 (SLT5008), and RS485MODBUS (SLT5009). 

Built for durability, Murata's soil sensors withstand outdoor conditions. Since they are deployed long-term in soil and water, the sensors must be rugged and corrosion-resistant. Murata's design features a robust casing with IP68-rated dustproof and waterproof protection. Low-voltage operation and corrosion-resistant materials ensure long-term reliability. Installation is straightforward - simply bury the sensor in the soil for immediate use in any environment. 

Primary applications of Murata's soil sensors include long-term monitoring of soil temperature, salinity, moisture, and fertilizer levels in agriculture, as well as irrigation system control. They are also used for water quality monitoring in rivers, lakes, and aquaculture ponds, and for soil and water research. 

CO₂ concentration monitoring ensures safety and enhances crop growth 

CO₂ (carbon dioxide) is a colorless, odorless gas at room temperature, released into the air through human and animal respiration and organic combustion, and absorbed by plants via photosynthesis. Global warming is largely attributed to increased greenhouse gases like CO₂, methane, nitrous oxide, and fluorocarbons, with CO₂ being the most significant contributor. Reducing CO₂ emissions is critical to mitigating global warming and preserving ecosystems. 

CO₂ concentration also affects human health. While CO₂ is used in dry ice and fire extinguishers, improper use leading to high atmospheric concentrations can cause CO₂ poisoning. The recommended indoor CO₂ level for proper ventilation is below 1,000 ppm. Frequent ventilation is essential in crowded spaces like homes and offices. CO₂ sensors, particularly NDIR (non-dispersive infrared) types, are highly effective for accurate monitoring and management. 

In agriculture, CO₂ monitoring is equally vital. Plants consume CO₂ during photosynthesis, and enclosed greenhouses often face CO₂ deficiency. Using CO₂ generators and sensors to regulate greenhouse CO₂ levels can enhance crop growth, yield, and quality. 

CO₂ sensor reliability varies by application. In agriculture, sensors must endure high-temperature, high-humidity environments, condensation, and even sulfur fumigation for disease prevention - conditions that are harsh for electronic devices. 

CO₂ sensors have diverse applications, including promoting photosynthesis in agriculture, managing HVAC systems in buildings, monitoring in-vehicle air quality, and detecting refrigerant leaks. Sensor selection depends on accuracy, reliability, environmental resistance, maintenance-free operation, size, price, and output interface requirements. Some applications prioritize compact size and affordability, while others demand long-term accuracy and durability without calibration.

CO₂ sensors for smart agriculture and greenhouses

Murata offers CO₂ sensors (IMG-CA0012-00) designed for smart agriculture and greenhouses. These sensors provide long-term stability, high measurement accuracy, and low maintenance. Their excellent temperature performance makes them ideal for greenhouses with significant daytime fluctuations and high humidity. Low drift minimizes excessive fuel use and ensures stable CO₂ application for higher yields. The Murata’s sensors feature moisture-resistant coatings, high-performance air filters, and built-in surge protection. Models with easy-to-install enclosures and cables are also available.

Murata's CO₂ sensors detect carbon dioxide concentrations using a non-dispersive infrared (NDIR) sensing principle. Inside the sensor, an infrared light source emits light through a gas chamber containing the air sample. CO₂ molecules absorb specific wavelengths of this infrared light. A photodetector measures the amount of light that passes through the chamber without being absorbed. By analyzing the reduction in light intensity at the CO₂-specific wavelength, the sensor accurately determines the concentration of CO₂ in the air. This method provides precise, stable, and fast measurements, making Murata’s CO₂ sensors ideal for applications like indoor air quality monitoring and HVAC systems.

Additionally, Murata's CO₂ sensors are suitable for building HVAC control and indoor environment monitoring. With a 10-year design life, duct-installable models simplify replacement. Automatic drift correction and maintenance-free operation enhance energy efficiency.

Conclusion

Soil sensors and CO₂ sensors demonstrate strong potential in advancing sustainable development goals. Precise soil monitoring enables water-efficient, fertilizer-saving, and high-yield agriculture. Meanwhile, CO₂ sensors ensure safety and boost crop productivity. Murata's soil and CO₂ sensors will play a critical role in achieving food security, environmental sustainability, and smart management, paving the way for a greener future for humanity and the planet.