Juli Ban, Product Manager (Function Devices), Murata
There is growing concern in the agricultural sector and governments, widely reported in the media, about food production and whether it will be enough to meet unprecedented demand in the future. Continuing population growth (particularly in developing countries), coupled with limited reserves of suitable land and labor availability problems, coupled with numerous environmental factors, mean that there is an increasing and frequent risk of shortages. in the food supply.
It is now widely recognized that technology will need to play a major role in next generation farming activities, thus contributing to the transition away from less efficient traditional methods and the existing reliance on manual labor. This technology will significantly increase the yield of crops per hectare of land and make better use of essential resources, in addition to reducing labor costs.
Increase in world food production
Based on United Nations figures, it has been extrapolated that the world population will grow from 7.900 billion to more than 10.000 billion in the next 35 years. As a consequence of this, there will be at least another 2.000 million more people than today who will have to be fed, quite a challenge considering that feeding the current population is already complicated. Combating climate change and protecting biodiversity makes it no longer acceptable to increase the area of arable land through deforestation. Other methods must be found to make better use of existing crop fields.
A key aspect for the adoption of smart agricultural practices will be the acquisition and subsequent analysis of data. Sensor devices will be installed on agricultural land in order to provide updated information on the main parameters affecting food production (such as air temperature, humidity, lighting levels, etc.). This will allow farmers to have the information required to respond to changing circumstances, whether they are short-term fluctuations in growing conditions or trends that will require a long-term solution.
Irrigation and fertilizers represent two major operating expenses for farmers. Similarly, the electrical supply of lighting needed by vertical farms and indoor fruit and vegetable farms will be among their main annual financial outlays. It is therefore essential to ensure that these aspects are used optimally; hence it is necessary to install advanced sensors.
Main sensor requirements
Sensors used in the agricultural sector must have certain characteristics to perform their assigned role effectively. First, they must be robust enough to support the application environment so that they can function continuously. Second, they must provide accurate data, otherwise decisions made by farmers based on this data could be incorrect and crop production volumes or quality could be affected. Finally, these sensors must be accompanied by the appropriate connectivity.
soil measurements
One of the many areas of agriculture where constantly updated parameter data will be very valuable is soil as it will allow farmers to know how much nutrient and salt ions are present and whether the amount of rainfall is sufficient. They will be in a position to find out whether they are using the correct amounts of fertilizer or whether the installed irrigation system is working satisfactorily, as well as to look for signs of groundwater contamination.
The distribution of the sensors in the soil will depend on the type of crop and the degree of monitoring of the parameters. For crops with a higher value (such as grapes used to make wine) a higher density of sensors will be justified. The frequency of data acquisition will also depend on the crop, as will the methods used. On outdoor farms updates every 30 minutes are likely to be adequate, while indoors it could be as low as 5 minutes.
As Figure 1 shows, the soil samples will basically consist of the soil mineral itself (in the form of grains), air spaces, and capillary water. Soil nutrients, along with fertilizer chemicals, will be transported in the capillary water. The detailed study of the state of the soil will require measuring the electrical conductivity (EC). In this way, data on the composition of the soil are obtained from the resistance properties of its components.
Figure 1: Composition of the soil.
One of the problems with existing soil sensing devices is that their accuracy can be negatively influenced by variations in temperature and excessive water content, as well as by the presence of chemicals. Another problem that must be considered is that the rocks located between the electrodes of the sensor can affect the results obtained. For this reason, a multi-electrode setup will offer much higher accuracy. The need to resolve these issues was what prompted Murata engineers to develop a more sophisticated soil sensor.
With the Murata soil sensor it is possible to continuously monitor the condition of the soil. This highly integrated device incorporates three detection functions that allow examining different parameters simultaneously. These functions are:
- A sensing element with nine electrodes to determine EC.
- A moisture sensing element that measures electrical permittivity, to provide a value of volumetric water content.
- A temperature sensing element.
The nine-electrode EC sensor is unique on the market. It allows the generation of various measurement patterns, thus eliminating uncertainty about the results obtained. The humidity sensor covers the range of volumetric moisture content between 0 and 60% and maintains a full scale humidity accuracy of ±3%. The temperature sensor supports a temperature range of -20°C to 60°C with an accuracy of ±1,0°C and applies a proprietary algorithm that compensates for the influence of temperature on EC measurements. The device incorporates another proprietary algorithm that allows obtaining the exact values of the fertilizer content, thus identifying possible excessive use.
Murata's soil sensor device offers high accuracy and is more economical than competitor solutions. It is supplied in a robust IP68 housing to protect against the ingress of dust and liquids. You can choose between UART, RS232E, RS485-MODBUS and SDI-12 interfaces, as well as wireless connectivity via a Bluetooth LE transceiver. Sensor data acquisition times are easily adjusted. Readings are taken every 30 minutes, so three AA batteries are capable of powering the device for a minimum of 6 months before replacing.
Before presenting this solution, Murata carried out extensive trials on various farms in Asia. He has been successfully used to analyze salinity levels in rice fields, fertilizer use in fruit trees, and irrigation efficiency in peanut fields.
Conclusion
A digital transformation of the agricultural sector must be launched to boost the food supply chain and alleviate scarcity problems. Innovations like the three-in-one soil sensor described above have the potential to make a substantial contribution to making farming more data-driven, thereby increasing productivity and lowering operating costs.
