Krone NIR Control dual with calibration model 14.3.1

The data can be georeferenced and easily communicated for example via agrirouter to a farm management software such as Next Machine Management. The yield and nutrient maps can be merged with seed and fertilizer application maps. Through this farmers and agronomists can improve their planning for the next season.

Procedure of near-infrared measurement

The function of a NIR sensor systems is shown in Figure 2. The passing material is separated from the sensor by a sapphire window. During the NIR analysis, the passing material is irradiated with infra-red light source of known spectrum. The reflected or re-emitted light is detected. To compensate for the temperature-dependent shifts in the spectrum, the system runs regular white and dark referencing. 
The measurement data are processed via an evaluation unit and converted into measurement values with unit specifications in a microcomputer using the calibration models stored for the parameters to be determined.

The measurement is performed continuously on the passing material. Measuring values are output every second when in measuring mode. Depending upon the requirements, mean values for user-specific time intervals, or live values, are displayed in real time.
The manufacturer specifies the measurement ranges shown in Table 2 for calibration model 14.3.1.

Table 2: Measurement range of Krone NIR Control dual with calibration model 14.3.1

The scope in the DLG Test is limited on substrates, which are described as manure according to the German Fertilizer Act, so on cattle manure, pig manure, mixed manure from cattle and pig manure, and liquid digestate from cattle or pig manure with renewable raw materials.

The DLG test is available for the measurement of the following ingredients:

• Dry matter content (DM in % Weight.)
• Total Nitrogen amount (N_Total in kg/m³)
• Ammonium nitrogen amount (NH₄­N in kg/m³)
• Phosphate content (Phosphorous Pentoxide; P₂O₅ in kg/m³)
• Potassium (Potassium Oxide; K₂O in kg/m³)

In order to cover a wide range of applications, the test attempts to use a diverse spectrum for each type of substrate:

• Cattle manure: 4 % DM – 9 % DM, where possible from dairy cows and fattened cattles 
• Pig manure: 2 % DM – 7 % DM, where possible from sow-keeping + fattened pigs
• Mixed manure from cattle and pig manure: concentration series as follows 10 %cattle : 90 %pig / 30 %cattle : 70 %pig / 50 %cattle : 50 %pig / 70 %cattle : 30 %pig / 90 %cattle : 10 %pig
• Liquid digestate from cattle or pig manure with renewable raw materials: 5 % DM – 8 % DM

The DLG approval can be awarded for individual types of manure and individual ingredients. To get a DLG recognition, at least the requirements for the measurement of the total nitrogen content (N_Total) need to be met. When the requirements for the measurement of the total nitrogen content are met, other ingredients can be freely chosen.

The process

Depending on each type of manure (cattle manure, pig manure, mixed manure from cattle and pig manure, liquid digestate from cattle or pig manure with renewable raw materials) five individual and as diverse as possible samples are measured and sampled on different farms. For this purpose, a subset of 3 m³ to 5 m³ is pumped from the previously stirred slurry storage in an intermediate tank. 

At the intermediate tank, a pump and a common piping system are installed. On the piping system one or more sensors to be tested and a bypass for sampling are attached. If necessary, a flow meter for the control of flow rates can be attached (see figure 3).

In a preliminary phase the collected manure is intensively homogenized in the intermediate tank by continuous circulation in a closed circuit.

Following this preliminary phase, the measured values of the sensor are documented. Afterwards subsamples for the reference analyses are then taken via the bypass while maintaining inflation around the closed circuit. In order to determine any possible influence on the sensor values, subsequently the flow velocity is varied and the measured values are re-documented.

The manure samples are clearly marked, frozen and stored frozen. Five suitable laboratories are commissioned with the reference analysis. Each laboratory receives partial samples of each manure. The analyses in the laboratory must be carried out using officially recognized methods, preferably wet-chemical methods.

For each manure and each ingredient, the arithmetic mean value is calculated as a reference value from the laboratory results. The assessment of accuracy is based on the relative deviations from the sensor value in comparison with the reference value.