We unify profitable farming and environmental protection
In modern agriculture the amount of nutrients in soil is commonly adjusted by the application of fertilizers. The fertilizer dose has to be carefully adapted to the plant demands, since under-supply as well as over-supply lead to reduced yield. In addition, excessive use seriously harms the environment if fertilizers are not taken up by crops but get washed into ground water. In order to apply the appropriate amount of fertilizers, precise knowledge of nutrient concentrations in the soil and plant needs is required.
At the moment open field crops are fertilized using slow-dissolving solid fertilizer, applied while sowing in an experience-based quantity. Once the fertilizer is applied, the farmer has no control on the rate in which it is dissolved and so when it is available for the plants, or has the possibility of correcting the dose during the growth of the crop. A system for calculating and applying on-demand fertilizers in open field crops, together with a fast and simple method for the routine surveillance of these nutrients is not yet available. Laboratory analysis or the complex application of several measurement procedures have to be applied at the beginning of the season. As a consequence, the applied fertilizer dose is often based on estimations, with adverse effects on environment and profit.
We have developed a full fertigation system composed of:
- A soil nutrient sensor system for the combined measurement of NO3, NH4, K and PO4 at the field. For the measurement, a soil sample is suspended in a universal extraction liquid. After filtration, the amount of dissolved nutrients is measured in this liquid. In this way, only a single extraction procedure followed by a single measurement is required, minimising the work for the generation of nutrient concentration maps and depth profiles.
- A software system which will receive the sensor data and process it together with crop growth models and weather data to calculate the required amount of fertilizers for each growth stage.
- A mixing and dosing unit, designed specifically for the requirements of an open field, and prepared to dissolve any needed fertilizer combination. The dosing unit can be coupled with any standard irrigation system, adapting the dose not only to the required amount of nutrients for each crop period but also to dynamically adapt to the variation of irrigation rate.
The three developed prototypes have been tested in a corn field in Brandenburg, Germany, during the season 2013. 25Ha test site in this field has been fertigated using the OPTIFERT prototypes. The soil and plants have been monitored and analysed periodically during the whole season, as well as neighbour 25Ha reference test, which was fertilized under standard practice. The performance of prototypes and test field have proven satisfactory.