GR1009606B - A system for the high-accurcy variable supply of granular fertilisers - Google Patents

Abstract

Novelty: an integrated system destined for the variable supply of granular nitrogen fertilizers is disclosed. Technical features: compared to existing systems, the invented one is able to accurately detect nitrogen lack in a very small region of plants; the spatial accuracy is of the order of one meter. It is composed of two subsidiary sections (the nitrogen detection section and the variable supply section) both being completely synchronized and intercommunicating. The operation of the system is automated from the detection calibration and the variable nitrogen supply up to the registration of the intervention data.

Description

DESCRIPTION

System of variable supply of granular fertilizer with high point accuracy.

The present invention relates to an integrated system for the variable delivery of granular fertilizer with high spatial resolution to agricultural crops. The system is mounted on an agricultural vehicle capable of entering fields during the growing season, so we recommend that the vehicle be a tractor (Figure 1, no. 10).

For variable fertilizer delivery, the fertilizer spreader (Figure 1, no. 1 ) fertilizes, with the amount of fertilizer required, the area detected by the system at a given time, as the vehicle moves through the field.

Detection is achieved with active multispectral sensors (Figure 1, no. 2A and 2B), which measure the point reflectance of the foliage at two wavelengths.

The spot fertilization rate is calculated by a computer (Figure 1, no. 3) that uses an algorithm (Narr = Nopt * √(1 - SI/ΔSI, Holland-Schepers 2010) that takes into account the values of the foliage reflectance.

Lubrication values feed an electronic device (Figure 1, no.

4) which gives the corresponding fertilization command to the appropriate fertilizer distributor (Figure 1, no. 1).

Variable delivery is accurately achieved in different crops (e.g. grain, maize, cotton) because the sensors (Figure 1, no.

2A, 2B) measure foliage reflectance at 730nm (red edge) and 780nm (near infrared) and the computer (Figure 1, no. 3) calculates the red edge normalized difference vegetation index (NDVI) based on the two wavelengths. This vegetative index is similar to the chlorophyll index which accurately estimates chlorophyll content in a wide range of crops that may differ in leaf area index, foliage architecture and leaf structure (Gitelson et al. 2005).

The variable delivery is achieved under any weather and time conditions, as long as the vehicle is able to enter the field, because the multispectral sensors (Figure 1, no. 2A, 2B, ..., 2h) are of an active type, which means that they emit and measure reflectance at their own pulsed wavelengths independent of those of visible light.

Common to the few variable delivery granular fertilizer systems on the market today are:

(a) Detection System: by placing sensors (Figure 2 no. 2) on the vehicle (Figure 2, no. 10) at a distance (height) of several meters from the target (foliage) (Figure 2 no. 8);

and,

(b) Distribution System: using a spinner spreader, the distribution of the fertilizer (Figure 2, no. 9) is done with a radius ranging from 5 to 15 meters (Figure 2, no. 11).

The long distance of the sensors from the target does not allow for pinpoint accuracy of detection, and fertilizer spreaders of this type do not allow for pinpoint accuracy of fertilizer distribution even if the detection system had such specifications.

The purpose of the present invention is to create methods and tools, with which the accuracy of diagnosing nitrogen deficiency in a very small area of plants will be maximized and the accuracy of fertilizer distribution in this area will be increased, so that the variable supply system can respond to spatial accuracy required in lubrication in that particular area. The system also can operate under any weather and time conditions to meet the rapid demands of agricultural crops.

According to the scientific literature, the spatial accuracy of variable delivery needs to be on the order of one meter to be compatible with the natural variation of soil properties, and therefore, to achieve effective nitrogen spot fertilization in agricultural crops.

The solution to this problem is achieved in two ways:

(a) by increasing the point accuracy of the diagnosis by placing active sensors (Figure 1, no. 2A, 2B) with high spatial resolution (at least 40,000 Hz) in close proximity to the foliage (60 cm) and,

(b) by replacing the rotary fertilizer spreader (Figure 2) used to date, with a fertilizer spreader (Figure 1, no. 1) of linear (one-dimensional) rather than surface (two-dimensional) release.

The fertilizer distributor of the invention distributes pointwise (linearly) (Figure 1 no. 9) the granular fertilizer between the rows of planting, through nozzles (Figure 1, no. 5A, 5B, ..., 5h) with point accuracy, the same as that of of orders it receives.

The number and distance of the nozzles between them depends on the type and size of the fertilizer spreader and the type of crop.

The system consists of:

1. Active nitrogen deficiency detection sensors (Figure 1, no. 2A and 2B).

2. Electronic computer for calculating the necessary amount of nitrogen (Figure 1, no. 3).

3. Device for calculating the speed of the system (Figure 1, no. 6).

4. Electronic device for calculating the release time of the amount of fertilizer calculated by the computer (paragraph 2) in combination with the speed of the vehicle (paragraph 3) (Figure 1, no.

4).

5. Fertilizer distributor (Drawing 1, no. 1), which executes the command received from the electronic device (paragraph 4).

6. Nozzle system of appropriate number (Figure 1, no. 5A, 5B, .. Bn).

The system is installed on a killivant (Figure 1, no.

7) and is connected to the PTO (Power Take Off) and the vehicle battery (Figure 1 no. 10) or only to the battery.

The system is programmed so that, after the initial settings, the calibration and variable fertilizer delivery functions are performed in an automated manner. The system layout is shown in Figure 1.

The initial actions are:

1. Connecting the kilibanda carrying the system to the vehicle for towing and transport.

2. Connecting the hydraulic pump of the distribution system to the PTO (Power Take Off) or the vehicle battery. Through this pump the fertilizer distribution system works (Diagram 1, no. 5A, 5B, ..., 5n).

3. Placement of the sensors (Figure 1, no. 2A, 2B) above different planting lines, at a height of 60 cm, on average, from the top of the foliage.

In the computer (Figure 1, no. 3) the constants for the specific crop are entered, such as the optimum nitrogen dose to maximize the yield of the crop (Nopt), the differential adequacy index (ASI) and the appropriate vegetative index (NDRE) is selected. according to Holland & Schepers (2010).

Calibration of the system for the specific field crop is achieved by processing the foliage data along a representative strip of the field.

During this minute process, the sensors (Figure 1, no. 2A, 2B) record the variation of the vegetative index values and the computer calculates (Figure 1, no. 3) the reference value corresponding to 95% of the normal distribution. This vegetative index reference value represents plants with nitrogen sufficiency and is used to calculate the sufficiency index (SI) according to the concept of "virtual reference" for the specific crop in the specific field (Holland & Schepers 2011).

After the calibration process, the system is now in normal operation mode. As the vehicle (Figure 1, no. 10) is in motion, the computer (Figure 1, no. 3) records the data from the sensors (Figure 1, no. 2A and 2B) and calculates the adequacy index (SI) based on of the reference value and then the nitrogen dose based on the reference value, the optimal nitrogen dose (Nopt) and the differential adequacy index (ASI) according to the algorithm (Holland and Schepers 2010).

The electronic device (Figure 1, no. 4) receives the nitrogen dose command from the computer (Figure 1, no. 3), and the vehicle speed from the speed sensor (Figure 1, no. 6) and sends its own of the final command to the fertilizer spreader (Figure 1, no. 1) with a frequency of 1Hz corresponding to approximately 1.2 meters on the planting line (Figure 1 no. 8) when the vehicle moves at a normal speed (4-4.5 Km/ h).

The variable rate fertilizer spreader (Figure 1, no. 1) executes the fertilizer dose command and the nozzles (Figure 1, no. 5A, 5B, ...5h) release the calculated amount of granular fertilizer once they reach the corresponding field area.

The whole process is carried out in real time and with a spatial accuracy of about 1 meter, when the vehicle is moving at the usual speed for field work (4-4.5 Km/h).

During calibration and variable flow lubrication, data is recorded as a function of the coordinates of each position from the GPS built into the computer (Figure 1, no. 3).

This data includes latitude, longitude and altitude, course, speed, date and time, values at various wavelengths and lubrication dose per sensor.

After the end of fertilizing with a variable fertilizer supply, the operation data is evaluated and verified.

Bibliography

Gitelson, A. A., Vina, A., Rundquist, D. C., Ciganda, V. & Arkebauer, T. J. (2005). Remote estimation of canopy chlorophyll content in crops. Geophysical Research Letters, doi: 10.1029/ 2005G1022688.

Holland, K. H., & Schepers, J. S. (2010). Derivation of a variable rate nitrogen application model for in-season fertilization of com. Agronomy Journal, 102, 1415-1424.

Holland, K. H., & Schepers, J. S. (2011). Active-crop sensor calibration using the virtual reference concept. In J. V. Stafford (Ed.), Precision Agriculture 2011 (pp. 469—479). Prague, Czech Republic: Czech Center for Science and Society.

Claims (3)

1. Method for calculating variable supply of nitrogen fertilization consisting of: (a) Acquisition of plant foliage reflected light signals from multiple sensors (Figure 1 no. 2A, 2B) at 730 and 780 nm. (b) Calculation of average values of the vegetative index NDRE from the 730 and 780 nm wavelengths of the reflected light. (c) Calculation of the reference value of the vegetative index NDRE=(R78o nm - R730 nm) / (R780 nm R730 nm) where B=foliage reflectance value at the corresponding wavelength. The reference value is the NDRE value corresponding to the cumulative 95% of the normal distribution of values from a representative strip of the field without the need to create a nitrogen-sufficient strip. (d) Calculation of required fertilizer supply through algorithmic calculation, based on the formula Napp = Nopt * √(1 — SI/ΔSI where Napp=nitrogen dose, Nopt=optimal surface nitrogen dose to maximize crop yield, SI=NDRE value / NDRE reference value and ΔSI=SI difference parameter between zero and optimal nitrogen dose. 2. A variable supply nitrogen fertilization device specially adapted to implement the method of claim 1, consisting of two sub-parts: the detection part and the variable supply part. (a) The detection section (Figure 1 no. 2 and no. 3) measures the foliage reflectance during the plant growth stage by active multispectral sensors with a frequency of at least 40,000 Hz (Figure 1 no. 2A, 2B) placed at a height 60 cm from the foliage. The computer (Figure 1 no. 3) then averages the foliage reflectance values, enters them into the algorithm to calculate the point units of fertilization required by the plants, and transfers the fertilization commands at a frequency of 1 Hz to the variable supply section (Figure 1 no. 2, no. 4 and no. 5). (b) In the variable supply section, the electronic device (Figure 1 no. 4) accepts orders for nitrogen doses on the planting line (Figure 1 no. 8) from the computer (Figure 1 no. 3) and sends the commands with a frequency of 1 Hz to the fertilizer distributor (Figure 1 no. 1) in real time, corresponding to every 1.2 meters on the planting line (Figure 1 no. 8) with a speed of movement of 4.4 kilometers per hour. The fertilizer distributor executes the fertilizer dose commands by releasing the calculated amount of fertilizer through nozzles (Figure 1 no. 5A, 5B, . 5n) with pinpoint accuracy the same as that of the commands it receives. The release of fertilizer is spot (linear) (Figure 1 no. 9) and not on wider surfaces like rotary fertilizer spreaders (Figure 2 no. 11). 3. A variable supply nitrogen fertilization device, according to claim 2, installed on a killivant (Figure 1 no. 7), which is connected to the Power Take Off (PTO) and the vehicle battery (Figure 1 no. 10) or only with the battery.