Precision Agriculture Practice: How to Optimize Irrigation and Fertilization through Soil Sensors?

In traditional agriculture, irrigation and fertilization often rely on the experience of farmers and unified field management, which can easily lead to significant waste of water resources and fertilizers. This not only increases production costs, but may also cause environmental problems such as soil degradation and groundwater pollution due to excessive irrigation and fertilization. With the development of technology, precision agriculture has emerged, and its core lies in "perception" and "execution". And soil sensors serve as the "nerve endings" of agriculture, becoming a key technology for achieving precise irrigation and fertilization.

1、 The 'Ear and Eye' Power of Soil Sensors: Sensing the Mystery of the Underground World

Soil sensors are data collection devices deployed in fields that can monitor key soil indicators in real-time and continuously. The main types include:

• Soil moisture sensor:

  By measuring the dielectric constant and other characteristics of the soil, it accurately reflects the volumetric moisture content of the soil. This is the most direct basis for determining whether irrigation is needed and how much irrigation is needed.

• Soil Conductivity (EC) Sensor:

  Soil conductivity is highly correlated with the concentration of soluble salt ions in the soil, which mainly come from fertilizers. Therefore, the EC value can indirectly reflect the fertility status of the soil, indicating "where fertilization is needed" and "how much is needed".

• Temperature sensor: Soil temperature affects seed germination, microbial activity, and nutrient decomposition rate, and is an important reference for adjusting agricultural activity time.

• Multi parameter composite sensor: integrates multiple sensing functions, can simultaneously measure moisture EC、 Temperature and even pH value provide a more comprehensive picture of soil health.

These sensors convert the collected analog signals into digital data, which is transmitted to the cloud or local platform through wired or wireless (such as LoRa, NB IoT, 4G/5G) networks to provide data support for decision-making.

2、 From data to decision-making: optimizing the closed-loop system of irrigation and fertilization

Having data alone is not enough, the key is how to use it to make scientific decisions. The application of soil sensors constitutes a precise management loop of "perception analysis execution".

1. Precise irrigation: on-demand water supply, say goodbye to "patting the head"

• Set threshold, automatic triggering:

  The system sets the soil moisture threshold for starting and stopping irrigation based on the water demand of crops at different growth stages. For example, when the soil moisture content in a certain area is detected to be below the set lower limit, the system will automatically or remind farmers to turn on the irrigation system in that area; When the moisture reaches the upper limit, it will automatically stop. This completely avoids ineffective irrigation.

• Draw a moisture distribution map: By deploying sensors at different locations in the field, a spatial distribution map of moisture in the field can be generated. Managers can clearly see which areas are dry and which areas are wet, thus achieving variable rate irrigation (VRI) for different regions, accurately replenishing only water scarce areas, and greatly improving water resource utilization efficiency.

2. Precise fertilization: supply fertilizer as needed to achieve "weight loss and efficiency improvement"

• Insight into fertility gains and losses: The distribution map of field fertility drawn by soil EC sensors can reveal the spatial variability of soil nutrients. The traditional uniform application of fertilizers is wasteful in areas with high fertility and insufficient in areas with low fertility. Based on this map, Variable Rate Technology (VRT) can be implemented.

• Fertigation synergy: In modern drip or irrigation systems, the combination of soil moisture and EC data is crucial. The system can monitor the concentration and distribution of fertilizer solution in the soil in real time after irrigation, ensuring that crop roots can efficiently absorb nutrients while absorbing water, achieving synchronous management and efficient utilization of water and fertilizer.

3、 Practical value and long-term benefits

The benefits of deploying soil sensor systems are comprehensive and far-reaching:

• Increasing yield and improving quality: Ensuring that crops are in the optimal water and fertilizer environment throughout the entire growth cycle helps to increase yield and improve the quality of agricultural products.

• Resource conservation:

  Can save up to 20% -50% of water usage and 15% -30% of fertilizer input, directly reducing production costs.

• Environmental protection: Reduce fertilizer leaching and deep leakage, effectively prevent non-point source pollution, protect groundwater resources, and promote sustainable agricultural development.

• Improve efficiency: Implement automation and intelligent management, reduce dependence on manpower, enable farmers to manage larger areas of farmland, and remotely monitor and operate through mobile phones or computers to respond to sudden weather changes.

Conclusion

Soil sensors, as the sensing cornerstone of precision agriculture, are profoundly transforming traditional agricultural production methods. It enables farmers to "see through" the soil, shifting from guessing based on experience to making decisions based on data, achieving refined and intelligent management of irrigation and fertilization activities. With the continuous advancement of sensor technology and the continuous decrease in costs, this technology will gradually move from large-scale farms to more widespread applications, providing a hopeful technological path for global agriculture to address water scarcity, ensure food security, and promote green development challenges