5,673,637 : Soil constituent sensor and precision agrichemical
delivery system and method
18 CLAIMS
What is claimed is:
- 1. A method for sensing substantially instantaneously at least one
chemical or physical constituent of a soil while traversing a field of
said soil and determining substantially simultaneously therewith an amount
of chemical to be applied, comprising the steps of:
- penetrating the soil of a first soil sample while traversing said sample;
- applying a voltage differential across said sample and determining
at least the complex component of the complex resistivity of said sample;
and
- determining a parameter related to said soil constituent from at least
said resistivity component while traversing said sample.
- 2. The method of claim 1 further comprising the step of:
- determining the amount of chemical to be applied to said sample while
traversing said sample.
- 3. The method of claim 1 wherein said physical constituent of said
soil is any of the constituents soil moisture, soil texture, cation exchange
capacity and organic matter.
- 4. The method of claim 2 further comprising the step of:
- applying the amount of chemical to said sample while traversing said
sample.
- 5. The method of claim 4 wherein the chemical applied is herbicide.
- 6. The method of claim 1 wherein said applied voltage differential
is a time-varying voltage differential.
- 7. The method of claim 1 wherein said applied voltage differential
is an alternating current voltage differential.
- 8. The method of claim 1 wherein said applied voltage differential
is applied so as to prevent oxidation-reduction reactions at the electrodes
applying said differential.
- 9. The method of claim 1 further comprising the step of:
- separating the real component of the complex resistivity of said sample
from the imaginary component thereof.
- 10. The method of claim 9 wherein said separation of the real and imaginary
components of the complex resistivity is accomplished by applying widely
separated excitation frequencies in order to separate such components by
frequency separation techniques.
- 11. The method of claim 9 wherein said separation of the real and imaginary
components of the complex resistivity is accomplished by the further step
of:
- utilizing soil textural characteristics to determine gain and offset
factors with which to effect such separation.
- 12. The method of claim 9 wherein said separation of the real and imaginary
components of the complex resistivity is accomplished by utilizing heuristic
gain and offset factors to determine soil textural characteristics.
- 13. The method of claim 9 further comprising the steps of:
- applying a fluid of first conductivity to a portion of said soil being
traversed and determining at least one component of the resistivity of
said soil in the presence of said fluid;
- applying a fluid of second conductivity to said portion of said soil
and determining at least one component of the resistivity of said soil
in the presence of said fluid; and
- determining from said components the resistivity of the soil matrix.
- 14. The method of claim 13 further comprising the steps of:
- subtracting the value of the conductivity of the said matrix from the
in situ measured conductivity to determine a parameter proportional to
the conductivity of the soil solute.
- 15. A system for sensing substantially instantaneously at least one
chemical or physical constituent of a soil while traversing a field of
said soil and determining substantially simultaneously therewith an amount
of chemical to be applied, comprising:
- means for penetrating the soil of a first soil sample while traversing
said sample;
- means for applying a voltage differential across said sample and determining
at least the complex component of the complex resistivity of said sample;
and
- means for determining a parameter related to said soil constituent
from at least said resistivity component while traversing said sample.
- 16. The system of claim 15 further comprising:
- means for determining the amount of chemical to be applied to said
sample while traversing said sample.
- 17. The system of claim 16 further comprising:
- means for applying the amount of chemical to said sample while traversing
said sample.
- 18. The system of claim 15 further comprising:
- means for applying a time-varying voltage differential across said
sample.
|
