12.8.2021
Area-specific crop management is more in demand than ever among farmers. Political requirements, environmental protection and increasing operational productivity mean that plant managers are constantly looking for new ways to apply existing resources, such as fertilizer, as efficiently as possible. Experts rely on plant sensors for this purpose. With ISARIA PRO Active and ISARIA PRO Compact, ISARIA offers farmers two reliable sensors for site-specific management. This raises the question: How does measurement work with an ISARIA plant sensor? We would like to answer this question for you below.
The plant sensors ISARIA PRO Active and ISARIA PRO Compact Differ in the Measurement methodology. The ISARIA PRO Active is considered an active plant sensor because it actively irradiates the plant population with its own light source. The ISARIA PRO Compact, on the other hand, uses sunlight as a light source and does not have its own light source. This is why we speak of a passive measurement principle. A passive plant sensor depends on a reference (irradiation sensor on the roof of the tractor), which measures the intensity of solar radiation. This makes it possible to relativize the reflection of the plant population. Both plant sensors measure the light reflected by the plant population in the same way while crossing the plant population.
The ISARIA PRO Active is an active plant sensor and can therefore be used independently of daylight. Four high-performance LEDs, which are integrated in the sensor head, act as the light source.
In this process, the artificial light source emits light waves in the near infrared and infrared ranges, which are reflected back by the plant population. This reflection is measured by a detector in the sensor. The process works independently of solar radiation, as leaf green in the near infrared and infrared ranges reflects approximately 7 times as strongly as in the visible range. The two sensor heads are guided between 80 and 120 cm above the upper edge of the inventory. In doing so, they measure vertically downwards. The operation and system setup of the plant sensor work via a separate terminal, which communicates with the sensor via Bluetooth.
The ISARIA PRO Compact is a compact plant sensor based on ISOSBUS for use during the day. This plant sensor is easy to install on the tractor's exterior mirrors. In addition, a light sensor is installed on the tractor roof to determine the current solar radiation. The two sensors on the mirrors measure the light reflection of the plant population diagonally downwards at an angle of 45°. This does not use a separate light source as output radiation, but solar radiation. It makes no difference whether the radiation is diffuse — such as when the sky is cloudy — or directly. A stable measurement is possible up to a solar angle of 10°. Even below 10°, further measurements can be made — however, the measurement result may be somewhat less accurate. In contrast to ISARIA PRO Active, this plant sensor is fully ISOBUS compatible and can be used with any ISOBUS-enabled Communicate terminal.
Good to know: Farmers do not have to estimate for themselves until when they can measure with the passive plant sensor. If the position of the sun is too low, the system warns that an error-free measurement is no longer possible.
Regardless of whether it is an active or passive plant sensor — both plant sensors measure the light reflected by the plants during the crossing. These reflection values are calculated in the ISARIA system. This results in two plant indices. The biomass index provides information on population density. The N supply index, on the other hand, reflects the current nitrogen supply to the stock. On the basis of these two indices, the correct amount of fertilizer for the current stock is calculated independently, depending on the chosen fertilization strategy. So that you always optimally supply your plant populations.
