IRRIGATION CONTROL SYSTEM

• US 20090050214A1
• Filed: 08/18/2008
• Published: 02/26/2009
• Est. Priority Date: 08/20/2007
• Status: Active Grant

• Current Assignee: Yissum Research Development Company of the Hebrew University of Jerusalem Ltd. (Hebrew University of Jerusalem), Netafim Limited (Orbia Advance Corporation, S.A.B. de C.V.)
• Original Assignee: Yissum Research Development Company of the Hebrew University of Jerusalem Ltd. (Hebrew University of Jerusalem), Netafim Limited (Orbia Advance Corporation, S.A.B. de C.V.)
• Inventors: Shani, Uri, Schweitzer, Abraham
• Granted Patent: US 8,051,871 B2
• Time in Patent Office: Days
• US Class Current: 137/78.300
• CPC Class Codes: A01G 25/167 Control by humidity of the soil itself or of devices simulating soil or of the atmosphere; Soil humidity sensors
• CPC Class Codes: G01N 7/10 by allowing diffusion of components through a porous wall and measuring a pressure or volume difference
• CPC Class Codes: Y02A 40/22 Improving land use; Improving water use or availability; Controlling erosion
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/189 Soil moisture sensing

Abstract

A tensiometer for use in determining matric potential of a soil comprising: a water inlet; a hydraulic coupler comprising a porous material for providing hydraulic coupling between water that enters the inlet and the soil; and a septum that seals water that enters the inlet against ingress of air via the porous material.

Claims

1. A tensiometer for use in determining matric potential of a soil comprising:

a water inlet;

a hydraulic coupler comprising a porous material for providing hydraulic coupling between water that enters the inlet and the soil; and

a septum that seals water that enters the inlet against ingress of air via the porous material.

2. A tensiometer according to claim 1 wherein the porous material comprises a geotextile.

3. A tensiometer according to claim 1 wherein the porous material is adapted to enable growth of plant roots therein.

4. A tensiometer according to claim 1 wherein the septum comprises a septum surface, at least a part of which is contiguous with water that enters the inlet.

5. A tensiometer according to claim 4 wherein the tensiometer comprises a water labyrinth having baffles.

6. A tensiometer according to claim 5 wherein a portion of the septum surface contacts the baffles.

7. A tensiometer according to claim 4 wherein the septum comprises a membrane and the septum surface is a surface of the membrane.

8. A tensiometer according to claim 7 wherein the membrane comprises a plurality of layers.

9. A tensiometer according to claim 8 wherein the layers comprise a first layer having a bubbling pressure greater than about a maximum absolute value of the matric potential of the soil in which the tensiometer is used.

10. A tensiometer according to claim 9 wherein the first layer is supported by at least one support layer.

11. A tensiometer according to claim 10 wherein the first layer is sandwiched between two support layers.

12. A tensiometer according to claim 1 wherein the septum has a bubbling pressure greater than about a maximum absolute value of the matric potential of the soil in which the tensiometer is used.

13. A tensiometer according to claim 9 wherein the bubbling pressure is about equal to one atmosphere.

14. A tensiometer according to claim 1 comprising an elastic member that resiliently presses the porous material to the septum.

15. A tensiometer according to claim 1 and comprising a water reservoir coupled to the water inlet.

16. A tensiometer according to claim 1 and comprising a device for providing a measure of pressure in the water reservoir.

17. An irrigation system comprising:

an irrigation pipe having at least one output orifice for outputting water from the pipe;

at least one tensiometer according to claim 1 coupled to the irrigation pipe so that water output from an orifice of the at least one orifice is constrained to pass substantially directly from the orifice through the hydraulic coupler.

18. An irrigation system according to claim 17 wherein the irrigation pipe comprises at least one emitter and an output orifice is an orifice of the at least one emitter.

19. An irrigation system according to claim 17 wherein the at least one emitter is an integrated emitter.

20. An irrigation system according to claim 18 wherein the at least one emitter comprises a plurality of emitters.

21. An irrigation system according to claim 17 wherein each of the at least one tensiometer is coupled to a same water reservoir.

23. Apparatus for use in determining matric potential of a soil comprising:

A tensiometer according to claim 1; and

a same water reservoir to which all the tensiometers are hydraulically coupled.

22. Apparatus for use in determining matric potential of a soil comprising:

a plurality of tensiometers; and

a same water reservoir to which all the tensiometers are hydraulically coupled.

24. Apparatus according to claim 22 and comprising a valve adapted to connect the irrigation system to a water source and operable to enable water from the water source to enter the reservoir and remove air therefrom.

25. An irrigation system comprising:

an irrigation pipe having at least one output orifice for outputting water from the pipe;

at least one tensiometer comprising a hydraulic coupler for coupling the tensiometer to soil irrigated by the irrigation system; and

a valve adapted to connect the irrigation system to a water source and operable to enable water from the water source to enter the at least one tensiometer and flush air from the tensiometer and coupler.

26. A tensiometer for use in determining matric potential of a soil comprising:

a water inlet;

a hydraulic coupler comprising a porous material for providing hydraulic coupling between water that enters the inlet and the soil; and

a valve adapted to connect the tensiometer to a water source and operable to enable water from the water source to enter the tensiometer and flush the hydraulic coupler.

27. A method of irrigating a field, the method comprising:

acquiring a calibration water matric potential for the field; and

irrigating the field with an amount of water responsive to the value of the calibration matric potential.

31. A method according to claim 27 wherein the field comprises plants and acquiring the calibration water matric potential comprises acquiring the matric potential when the plants exhibit relatively small water demand.

32. A method according to claim 27 wherein irrigating the field with an amount of water comprises providing a pulse of water.

33. A method according to claim 32 wherein providing an amount of water comprises acquiring a water matric potential measurement for the field in addition to the calibration water matric potential, comparing the additional water matric potential measurement to the calibration water matric potential, and irrigating the field with an amount of water responsive to the comparison.

34. A method according to claim 33 wherein comparing the additional water matric to the calibration matric potential comprises determining their difference.

35. A method according to claim 34 wherein providing a pulse of water comprises providing the pulse responsive to the difference.

36. A method according to claim 27 wherein providing water comprises providing water continuously.

37. A method according to claim 36 wherein providing water continuously, comprises determining an irrigation period responsive to the calibration water matric potential and providing water continuously for the determined irrigation period.

38. A method according to claim 37 wherein determining the irrigation period comprises determining the irrigation period responsive to a difference between the calibration water matric and a previously determined calibration water matric.

28. A method according to claim 28 wherein irrigating a field comprises performing an irrigation cyclically.

29. A method according to claim 28 wherein irrigating the field cyclically comprises irrigating the field in diurnal cycles.

30. A method according to claim 29 wherein acquiring a calibration water matric potential comprises acquiring a calibration water matric potential at least once a day.

39. An irrigation system comprising:

an irrigation pipe having at least one output orifice for outputting liquid from the pipe;

at least one hydraulic coupler coupled to the irrigation pipe so that liquid output from an orifice of the at least one orifice passes through the hydraulic coupler; and

at least one sensing means coupled to the hydraulic coupler to sense a property associated with liquid in the hydraulic coupler, responsive to which property output of water via the at least one orifice is controlled.

40. An irrigation system according to claim 39 wherein the sensed property comprises matric potential.

41. An irrigation system according to claim 39 wherein the sensed property comprises moisture content of the hydraulic coupler.

42. An irrigation system according to claim 39 comprising a controller that controls output of water via the at least one orifice responsive to the sensed property.