ES2396322B1 - Provision for measuring soil parameters, and method of use - Google Patents

Abstract

An arrangement for measuring soil parameters includes a soil moisture and salinity sensor, capacitive or condenser based, a predetermined moisture transfer medium, located in a volume adjacent to said sensor, such that the transfer medium substantially occupies the field of influence of said sensor. The transfer medium is arranged so that moisture can be transferred with the soil to be measured, and said sensor is intended to measure and produce data representative of the volume content of water of said transfer medium. Means for processing the sensor data determine both soil moisture and soil salinity of said medium. Using the volume content of the soil moisture measured and the moisture release curve of the medium, it is possible to deduce the soil matrix potential. The salinity of the measured medium corresponds to the salinity of the soil that is in a position capable of transferring moisture with the transfer medium.

Description

Provision for measuring soil parameters, and method of use

The invention relates to the measurement of the matrix potential of soils and the salinity of soils.

BACKGROUND

The retention and movement of water in soils, its absorption and transport in plants and its loss or elimination in the atmosphere are all phenomena related to energy. All substances, including water, have a tendency to transform or change from a higher energy state to a lower energy state. Water movements in soils will generally occur from an area where the energy level of the water is high (wet soil) to an area where the energy level is low (dry soil). If the relevant energy levels are known at various points in the soil, then it is possible to predict the direction of water movement.

  Three important forces affect the energy level of soil water.

First, the adhesion, or attraction that the soil matrix exerts on the water, provides a matrix or tensor force (responsible for adsorption and capillarity phenomena) that markedly reduces the energy state of the molecules of adsorbed water. To a lesser extent, cohesion forces, which describe the attraction of water molecules to each other, decrease the state of energy. Together, these forces produce a suction force inside the ground.

Second, the attraction that ions and other solutes exert on water gives rise to osmotic forces, which tend to reduce the level of energy in the soil solution. The osmotic movement of pure water that is produced through a semipermeable membrane to enter a soil solution is evidence of the low energy state of the soil solution.

The third main force that acts on soil water is the force of gravity, which tends to attract water down. The energy level of water at a given height within the soil profile is, thus, greater than that of water at a lower height. This difference in energy levels causes water to flow down.

It is useful to compare the energy levels of soil water with that of a sample of pure water outside the soil, in an environment that is maintained at standard pressure, temperature and height levels. The difference between the energy levels of pure water and soil water is called the potential of soil water.

The potential of soil matrix on water is always negative, because a certain force is required to extract water from the soil matrix, which implies that water is moving from a lower energy state to the state of Higher energy of pure water.

Each type of soil has the ability to retain a specific volume of water due to its texture and its volume of pores or porosity of the soil (the empty spaces between solid colloids). The matrix force or the matrix potential (\ m) that is produced as a result of the phenomena of adhesion (or adsorption) and capillarity, influences the retention of moisture in the soil, or the total amount of water stored in the soil, as well as in the movement of soil water.

The volume of water contained in the soil when it has been irrigated and completely drained (the instant of time in which the maximum amount of water is contained against gravity) is called the field capacity of that type of soil.

Consequently, a type of fine textured soil, such as clay, contains, by virtue of its physical nature, a large number of small pores and capillary channels in which water can be retained against the attraction of gravity , due to the matrix potential exerted by the soil on the soil water. In contrast, coarse, sandy soil has a smaller number of pores, although larger, and in which a lower matrix potential contributes to a lower potential for water storage in the soil and a lower field capacity.

The size and quantity of the pores in the type of soil and a given water content in the soil in a given instant of time determine the matrix potential by which the water adheres to the soil particles in this type of soil. . This matrix potential is equivalent to the negative tension (suction matrix potential) that the roots of the plants have to overcome to extract water from the soil for absorption.

The permanent wilting point is defined as the water content for which plants are no longer able to extract water from the soil with sufficient flow or velocity to meet their physiological needs. The physiological needs of plants are determined by the loss of water in the atmosphere (evaporation), and at the point of wilting the plants wilt and die. The permanent wilting point is usually reached at a matrix potential of –15 bar.

A fundamental practical utility of the concepts of field capacity and wilting point is the determination of a flow of soil water available to plants (PASW - “Plant Available Soil Water Range”). The storage of water in the soil available for plant use is generally calculated as between the field capacity and the point of permanent wilting.

Different soils may have relationships between impregnation or water content and the matrix potential (of tension or suction) that differ greatly (for example, a sandy soil can retain less than 5% of water content at a matrix potential of -15 bar, while a clay soil is able to retain that amount three times). Clearly, the more compact a mixture or compound of soil, the lower the capacity of retaining soil moisture, as a result of the volume of pores or reduced porosity, is also true in reverse. Consequently, different absolute amounts of water are stored in different soil textures.

The concept of water storage available for plants in the soil is an important factor in determining the amounts of irrigation for a crop field or other soil-plant system. For practical reasons, excess irrigation quantities with respect to field capacity are lost. This is because the excess soil water is removed by percolation, and this should be avoided in the interest of conserving water resources. There is also the risk of elimination by dragging or leaching of salts and beneficial soluble chemical compounds, from the area within which the crop extracts soil water containing these salts and chemical compounds.

The relationship between the volume content of the water in the soil (%) (which is the amount, in percent, of the soil water that is retained by the soil, based on volumetric calculations) and the soil water stress (suction, matrix potential) is called a water retention characteristic, and this relationship can be described mathematically with the use of a soil water release curve.

Gravimetric content of soil water = (ratio in% between kg of water / kg of soil) x 100 = both percent

Volumetric content of soil water = (the ratio between water weight / dry soil weight) x (specific density of dry soil / water density) = cm3 of water / cm3 of soil

A tensometer is but one of a certain number of devices that are used to measure the force thanks to which the soil retains water, which, in turn, is related to the degree of difficulty that the root system of a Plant found to extract water from the soil. While there are many other devices, tensometers are typically used by farmers and plant and soil researchers to measure this soil characteristic.

The parameter measured by a tensometer is provided in units of centibars (cb) and millibars (mb), and is known as the "soil matrix potential" (\ m). In recent years, the equivalent in the decimal metric system (units of the International System), the kilopascals (kPa), has also been adopted as a unit of measurement of the soil matrix potential. The soil matrix potential indicates the degree to which the plant needs to create an energy differential in its root system, in order to initiate the displacement of moisture from the soil into its root system.

  The tensometers provide their measurement, as mentioned, in centibars, with 100 centibars equivalent to one bar. The higher the reading in centibars, for example, 40 cb, the more difficult it is for the plant's root system to extract moisture from the surrounding soil, and conversely, the lower the reading, for example, 10 db, It is easier for you.

Tensometers are relatively simple devices that comprise a hollow tube provided with a tip of ceramic material porous to water but impervious to air (specifying this impermeability by a certain air inlet value, of, for example, 1 bar), which forms the lower end of an elongated and waterproof tube. The tube is filled with water and sealed by means of an upper cap. A vacuum measuring device is fixed to the upper cap, and the small volume of air remaining above the water, inside the tube, is used to measure the pressure inside the tube. The tube is then buried in a hole made for this purpose in the ground, so that the ceramic tip is in intimate contact with the ground and at a certain depth within the soil profile.

When the soil matrix potential is lower (more negative) than the equivalent pressure inside the tip of the tensometer, which occurs when the roots of the plant draw water from the soil surrounding the ceramic tip of the tensometer, the water is It travels from the tensometer along a gradient of potential energy to the ground, through its saturated porous cup. This action creates a negative suction or tension, which is detected by the pressure measuring device as an increase in the negative (vacuum) pressure at the top of the tube. The flow of water into the soil continues until equilibrium is reached, and the suction outside the tensometer equals the soil matrix potential. Once rain or irrigation has occurred, the porous spaces within the soil fill with water. The water will then move back, through the ceramic tip, into the tube of the tensometer, due to matrix forces that are now lower, which in turn decreases the negative pressure (vacuum) of the measuring instrument.

The exchange of water between the tensometer and the ground on which it is located occurs only at a specific negative pressure (suction, matrix potential) of the ceramic tip. A tip of ceramic material with an air inlet value of 80 cb and on which a matrix potential of 100 cb acts will allow air to travel inside the tensometer tube. As soon as this happens, the negative pressure of the instrument will quickly fall to a value close to 0 cb, and the measurement provided by the instrument will not reflect the predominant real matrix potential of 100 cb, so the instrument will not be, consequently , usable under such conditions. In order to rectify this situation, the tensometer tube must be filled with water. It will be necessary to operate a manual vacuum pump, fixed to the top of the tensometer tube, to extract water from the ground through the ceramic tip of the tensometer, in order to purge any air bubbles that have been trapped inside the ceramic tip with water. This correction arrangement will once again establish the exchange of water only (inside and outside) between the soil and the water reservoir or accumulation of the tensometer tube, so that it is possible to take appropriate measures by means of the tensometer.

The installation of the tensometers according to the following lines of action is typical:

•

 They are installed shortly after the sprouting of the plants, between healthy plants with an average size and in a place that represents an average soil type of the planted crop.

•

A tensometer is usually installed at a depth for which the root density is maximum, for example, 30 cm, and another can be placed in the vicinity of the lower part of the active root zone, for example, at 60 cm , which constitutes a profile measuring station. These depths may vary according to the type of crop.

•

 Usually one or two seasons are used per crop of the same age and variety. It is possible to use other stations to reflect changes in soil topography. The readings should be taken at the same time each day, preferably in the morning, taking into account that the fluctuation of the soil matrix potential may require more than one reading per day.

•

 At a minimum, readings should be taken every two days on medium textured soils, and every day on light textured soils.

•

 It is advisable to record the tensometer readings with 30-minute intervals and continuously, in order to generate sufficient data on which to rely to make decisions regarding irrigation control. Tensometers with the possibility of recording or memory are provided with a pressure transducer instead of a manual pressure measuring device.

  Unfortunately, tensometers present various problems, including those described above, and operate within a limited measurement range, which, in the best case, is between 0 cb and 80 cb. Tensometers require specialized implementation procedures and include the use of water from which the gas has been removed. The air tends to penetrate the ceramic material of the sensor, especially when the ground tension exceeds the air inlet value. For temperatures below zero, the water in the appliance freezes, leaving it non-operational. The device is fragile and, despite its simple construction, requires continuous maintenance. The type of maintenance includes completely filling with water from which the gas has been removed, performing a vacuum pumping in order to purge the air from the device, as well as the need to periodically add anti-algae substances, in order to avoid seaweed development

In addition, a tensometer attracts the roots of the plants in its immediate vicinity, because it is a constant source of moisture. The last of the aforementioned problems may undermine the relevance of the measures taken, since the measuring point on the ground on which the tensometer is located can now have a root length density per volume of soil significantly greater than the surrounding crop .

A tensometer is limited in its ability to determine the matrix potential, which must be between 0 kPa (saturation) and 80 kPa (dry). This is mainly due to the fact that the vacuum measuring device, or pressure gauge, measures a partial vacuum with respect to the outside atmospheric pressure, and the fact that the general failure of the water columns in the macroscopic systems that have occurred to withstand voltages that exceed 1 atmosphere or 1 bar, or 100 kPa. Some agricultural crops are subject to controlled soil moisture conditions that exceed this threshold, and therefore the tensometers cannot be used reliably in these applications.

The matrix or tensor potential is described here as a force per unit area, or pressure, that has units of pascals or megapascals (1 MPa = 10 bar, 100 kPa = 1 bar). An atmosphere is equivalent to the pressure exerted by a 100 cm high water column.

There are also problems related to the reading interval and associated with soil texture. For example, the hydraulic contact between a matrix of coarse-grained sand and the tip of the tensometer is interrupted more easily than in soils with heavier or more compact texture (below 85 kPa).

A tensometer is not compensated in depth. The tensometer equation is:

'm =' gauge + (zgauge - ztip)

The vertical distance from the plane of the zgauge measuring device to the ztip tip must be added to the matrix potential measured by the measuring device (expressed as a negative amount) in order to obtain the matrix potential at the tip depth. This takes into account the peak or maximum positive at the depth of the tip of ceramic material, exerted by the water column of the tensometer located above.

The accuracy of the tensometer is not more than +/- 1.2 kPa in wet conditions. A higher resolution at the “wet end” would make it possible for tension measurement technology to be applicable in other markets, such as nurseries and greenhouses. Containment means, consisting mainly of materials such as peat, bark, sand, perlite and vermiculite, are combined in order to form a mixture that maintains a large percentage of the volume content of water. However, a measure of the matrix potential of between 8 and 10 kPa indicates that the mixture is a relatively dry medium.

Tensometers cannot be used immediately after installation. The sensor tip has to soak for a couple of days in water devoid of gas. Allowing the tip to dry completely would leave the instrument useless for measurement until it got wet again.

Depending on the hydraulic resistance of the tip (cup) of the tensometer and the surrounding soil and the contact area between the tip and the ground, the response of the tensometer, for some instruments, can be delayed behind the changes of suction in the ground , that is, there is a finite response time.

  Tensometers do not tolerate frost. If the water inside the tube freezes, the expansion caused by the formation of ice is potentially capable of destroying the instrument.

The installation of the instrument can cause problems, especially in deep installation, for which the tip of the tensometer has to be pushed into a slightly under-sized hole located at the bottom of a larger access hole. The tip can break and detach easily while being pushed into the under-sized hole located in a lower position that cannot be seen.

Air bubbles often appear inside the tube filled with water that connects the porous tip with the pressure gauge. This occurs due to the reduced solubility of the gases at low hydrostatic pressures (as well as at high temperatures), and also because of the diffusion of the gases from the existing gaseous air phase in the unsaturated soil, through the porous walls of the tip of the tensometer. The appearance of these bubbles does not directly deny the measurement but reduces their sensitivity.

Consequently, tensometers require intensive maintenance that requires continuous work. The risk of not being able to take tensometer readings persists because the instrument has stopped working due to lack of proper maintenance.

A tensometer that provides a measurement point is not very useful for indicating the dynamics of the soil moisture profile through the area of the crop roots. It is common practice to use three to four individual tensometers to provide measurement points across the soil profile, which can triple or quadruple the requirements of manual maintenance, already intensive.

Tensometers are not able to measure increasing and decreasing levels of salinity, since the wall of the porous cup of the tensometer is permeable to both water and solutes. The solutes contained in the soil solution diffuse freely inside the cup, so that the water contained in the tensometer tends to adopt the same composition and concentration of solutes (osmotic potential) as the water in the surrounding soil.

The accuracy of the instrument and the accuracy of the measurement of the matrix potential for the purpose of scheduling commercial crop irrigation is of vital importance to the person responsible for growing the crop, since the economic performance of its exploitation depends on the quality of these measurements.

In addition, it is known that for a particular negative tension of soil water, the crop will be subjected to a situation of lack of water. Clearly, the ultimate goal is to provide information for adequate crop control based on accurate tensometer readings, since these will be used to make fundamental decisions for irrigation control.

5 Not only are the water content and its associated matrix potential important for irrigation programming over time, but also the regulation of the concentration of fertilizer in the soil. More particularly, it is of fundamental importance that there is a contribution of beneficial solutes in the soil water (such as those provided by the fertilizer) at a depth that is in the area of active absorption of the crop's root system. Fertilizing salts are easily washed away or eliminated by leaching from the root zone in humid environments, as a result of rains, or in arid environments, as a result of irrigation practices from above.

It is possible that naturally accumulate concentrations of harmful salts on the soil surfaces of arid or semi-arid regions due to the effects of meteorological agents on rocks and minerals, aided by insufficient rains that are not able to wash these salts from the upper layers of

15 floor When irrigation is practiced, there will also be a potential risk of damaging the health of the crop in areas where salts from irrigation water and fertilizer salts accumulate in the root region.

In poorly drained soils, the downward movement of irrigation water and fertilizer salts towards groundwater or groundwater is impeded, leaving salts in the soil that will creep up later, to the surface, according to the water of irrigation evaporates. This creates a saline soil. Historically, large increases in the demand for crop food worldwide have been met by extending irrigation practices. However, in many areas the need for good drainage was overlooked, and the salinization procedure has been accelerated.

  Saline concentrations may also be increased in the root zone as

25 as a consequence of the rise of water saturation layers, or groundwater layers, or the horizontal movement of fossil salt deposits, which move over impermeable geological layers. These can finally ascend or flow to the ground surface in the lowest or most depressed parts of the land, leading to the formation of salt leaks.

In arid areas of the world, where evaporation is intense, the accumulation of salts in irrigated soils must be controlled to ensure the success of plant production and to stop fertilizer leaks to waterways.

Soil salinity and its inseparable water content can be used to determine the dynamics of fertilizer displacements through the soil profile.

It was the verification of the exposed disadvantages of the current methods for measuring the humidity and salinity of the soil that motivated the proposal of the following device and installation method.

In sum, the inventors have developed a method and means capable of measuring and monitoring the volume content of soil water, soil matrix potential and soil salinity in a wide variety of soil types.

The arrangement and method are aimed at providing certain advantages over existing technology, and have the following qualities:

 one.

Increased accuracy and precision.

2.

 Increased measurement interval.

3.

 Increased measurement resolution.

Four.

 Ability to use in a variety of soil types.

45 5. There is no need for calibration (it uses a factory-original calibration and a unique data processing model).

6.

 Almost continuous tracking ability.

7.

 Immediate use capacity.

8.

Delay time reduced.

 9.

Simplified installation

10.

 Sensor that does not require maintenance.

eleven.

 Capacity for depth compensation (calibration is not necessary).

12.

 Frost proof sensor.

13.

 Solution to the problem of profile measurement.

14.

 It does not attract roots that can adversely affect or distort recorded data.

15. Ability to simultaneously measure the salinity of the soil solution, the volume content of the soil water and the matrix potential.

In order to suppress the need to calibrate a specific soil salinity sensor when measuring soil salinity in hundreds of different soil types, the invention, in a preferred arrangement, provides a single specific calibration equation of the soil. sensor. This calibration equation can be applied to all sensors that are manufactured after sensor normalization. The sensor is calibrated for the matrix potential and the salinity of the soil solution (salinity of the pores water) only in the predetermined means of displacement or transfer of moisture that has sufficient volume and is located around said sensor , such that said transfer means substantially occupies the field of influence of said sensor, and said transfer means is located in moisture communication with the soil that is desired to be measured with said particular sensor, and not for the surrounding soil with the that the transfer medium maintains hydraulic contact and moisture exchange.

What the inventors describe here is a method and means to measure the water content in the soil and the salinity of the soil within a single transfer medium for which the determination of the soil matrix potential is reduced to the mere use of a query table. The combination of the sensor and the transfer medium is calibrated once and remains true throughout the time of use of the transfer medium.

This solution is based on the fact that the transfer medium has the property of allowing the displacement of available solutes in soil moisture to and from the surrounding soil.

In addition, it is important that the sensor's field of influence for the measurement of soil moisture and salinity be completely located within the specified transfer medium. For sensors that use electromagnetic techniques and that are used to determine soil moisture and salinity, the field of influence of radiated electromagnetic radiation remains, preferably, fully within the volume of the transfer medium.

The use of a specified transfer medium ensures that the measurements taken by the sensor, as well as the data processing model, calibrated only for the specified transfer medium, provide an accurate value of the soil matrix potential. According to the model, it is possible to simultaneously measure the volume content of water in the transfer medium and, therefore, the salinity of the soil solution entering the transfer medium.

The inventors have developed an arrangement of elements that, when used in a predetermined way, provides a way of measuring the matrix potential and the volume, associated and measured, volume of soil water of the transfer medium (in order to deduce the matrix potential), as well as the salinity of the soil solution that is introduced into the transfer medium.

The obvious advantage of said arrangement and method is that only a combination of elements has to be calibrated (the elements consisting of the sensor, the transfer medium and the data processing model). This calibration is performed in the laboratory, with the type of transfer medium to be used, and the resulting calibration equation is then valid for all sensors that are manufactured (for that particular physical construction). The transfer medium is arranged in such a way that its displacement or moisture transfer characteristics make the model usable in most types of soil. In addition, this apparatus and this arrangement are based, not on the matrix potential detected with the use of the tensometer principle, but on the measurement of the complex dielectric constant of the transfer medium in order to deduce the total volume content of water of the soil in the transfer medium, with the use of an electromagnetic sensor that does not need maintenance and that is insensitive to the measurement interval. The calculation of the soil matrix potential is performed using a previously obtained soil water release curve (calibration equation), deducted for the transfer medium.

In the most useful way, the arrangement does not require adjustments or corrections of any kind between uses, for a wide variety of different soil types. Already at the place of employment, a spectacular arrangement, previously calibrated, including the default transfer medium, just needs to be installed. Due to the automated techniques of measurement and data collection, it is possible to collect useful data for presentation to the user in an adequate time and without any unwanted delay caused by the operation of the measuring devices. The measurement results are given in well-known units, that is, the matrix potential in kilopascals (kPa) and the salinity of the soil solution in milli-Siemens per centimeter (mS · cm-1).

BRIEF DESCRIPTION OF THE INVENTION

In the invention, contemplated in a broad aspect, the method of measuring soil parameters comprises the steps of:, or placing said sensor in a position adjacent to,

a) placing a capacitive base soil moisture sensor within a predetermined means of displacement or transfer of moisture that has sufficient volume and that is located around said sensor, such that said transfer means substantially occupies the field of influence of said sensor, and said transfer means is located in moisture communication with the ground that is desired to be measured with said sensor, and

b) measure the complex dielectric constant of the transfer medium in order to deduce the volume content of water from said transfer medium with the use of said sensor, and process said measurement to determine the matrix potential of said soil.

An alternative to step a) is a capacitive base soil moisture sensor, a predetermined means of moisture transfer, located in a volume surrounding said sensor, such that the transfer means occupies the field of influence of said sensor, and said transfer means is in moisture communication with said floor, in which a) said sensor and said predetermined transfer means are located on the floor of which one or more characteristics are to be measured.

Even in a further aspect of the invention, a mixture of compounds suitable for placing on the ground, and also suitable for allowing the movement of water and solutes from said surrounding soil, and for the common location of one or more sensors for The measurement of the water content and the salinity of the soil, for said surrounding soil, comprises diatomaceous earth or fine sand, either small pellets or glass particles or other suitable elements, or a mixture thereof.

In yet a further aspect of the invention, a capacitive sensor is placed outside a container permeable or transparent to the radio frequency but impervious to the solution, which is filled with a transfer medium intended to measure the matrix potential. , of the water content in the soil and the salinity of the transfer medium. This embodiment may be applied to a configuration in which the soil to be measured is within a volume contained in the transfer medium.

Specific embodiments of the invention will be described below in some additional detail and in relation to the accompanying figures, which serve for their illustration. These embodiments are provided by way of illustration, and are not intended to be restrictive of the scope of the invention. Suggestions and descriptions of other embodiments may be included within the scope of the invention, but they may not be illustrated in the accompanying figures, or alternative features of the invention that are not described in the figures may be shown in the figures the memory.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a single coil / transfer medium installation in a surrounding soil environment, according to the invention;

Figure 2 shows an installation of multiple coils / transfer medium in a surrounding soil environment, according to the invention;

Figure 3 is a schematic representation of detection devices and visual presentation of soil moisture and salinity parameters;

Figure 4 illustrates a diagram of soil moisture and salinity, showing the tendency exhibited by water content and soil salinity over time;

Figure 5 illustrates a variety of forms of the transfer medium; Y

Figure 6 illustrates a variety of sensor configurations.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Figure 1 illustrates a sensor 10 located in a single / composite coil installation 12 which, in turn, is located on the floor 14, whose moisture content and soil salinity characteristics are to be measured. Each of the elements described above is illustrated in cross-section in Figure 1, although the three-dimensional characteristics are immediately deduced.

The sensor of this embodiment is capacitive, and an example thereof is described in US Patent No. 5418466, of the same assignee as the Patent associated with this Report. However, any sensor that uses electromagnetic radiation can be used to provide the ability to measure soil moisture and salinity.

The sensor used in this embodiment refers to a device capable of providing moisture and salinity measurement. In particular, to a sensor and the method to use it that provide values of the dielectric constant of a transfer medium. The values then need to become a volumetric moisture content in the soil (mm3), a soil matrix potential \ m, in kPa, and a soil salinity, in deci-Siemens per centimeter (dS / cm).

A sensor apparatus comprising a pair of condensing elements (conductive rings 16) has been arranged (shown in cross section in Figure 1) in a tuned circuit 18. The details of the tuned circuit will be known to those skilled in the art, and is It is possible to obtain general details of the circuit of the previously mentioned US Patent No. 5,418,466.

The sensor described in US Patent No. 5,418,466 uses two metal rings to form the plates of a condensing element (C). The rings form a part of an LC oscillator, so it oscillates at a frequency that depends on the values of L (inductance) and C (capacity). If C is constant, like L, in an LC circuit, its resonance frequency f is inversely proportional to the permissiveness of the surrounding transfer medium. Permitivity is the ability of the transfer medium to resist the formation of an electric field within it. Conversely, the dielectric constant of a material is the measure of the amount of electrostatic energy that can be stored per unit volume when a unit of voltage is applied to the transfer medium.

The sensor capacity is a function of the surface of the sensor rings, their separation distance and the dielectric material located in the vicinity of the rings. In the case of the sensor, the area of the rings and the separation distance between them are fixed, and therefore the capacity (C) is a mere function of the dielectric constant of the surrounding material, which, in the embodiment according With the invention, it is a moisture transfer medium. If the inductance (L) is fixed, then the oscillation frequency is only a function of the capacity (C), which (as already established), is a function only of the dielectric material. Thus, as the moisture content of the dielectric material changes, so does the dielectric constant of the material and, consequently, the oscillation frequency is related to changes in the moisture content of the soil.

The switching between the two sensor frequency modes is achieved by switching between two fixed inductors connected to the LC oscillator. The oscillator then oscillates within two different frequency bands (above and below 27 MHz), and varies in these bands depending on the dielectric constant of the material in the vicinity of the rings (that is, the ground). Operating in one of the modes (that is, preferably at 150 MHz, which is well above 27 MHz), the effect of varying the salinity content results in a negligible effect on the oscillation frequency, and, therefore, The output of the oscillator depends fundamentally on the soil moisture. For operation in the other mode (that is, preferably at 5 MHz, which is widely below 27 MHz), the oscillation frequency depends not only on changes in soil moisture (as in the first mode), but which also depends, in part, on changes in salinity. Simplifying, if the response obtained in the first way is based on the response obtained in the second way, then the result would be an indication of the salinity of the soil.

A profile of the distribution of soil moisture and salinity is obtained by placing multiple sensors at various depths, typically 10 cm apart from each other in a coaxial arrangement. In the arrangement for measuring humidity and salinity according to this embodiment, the sensors are installed in a circuit board. The plate also acts as a circuit board that can be inserted into, and removed from, a hollow tube intended to be placed within a predetermined transfer means, in turn located on the ground to be measured. Most likely, the measurements represent the actual characteristics of the soil, since the transfer medium immediately adopts the soil matrix potential of the surrounding soil. This is very different from the existing and previous sensor arrangements. Most of the previous arrangements for the placement of the sensors did not present a high probability of accurately measuring the characteristics of the adjacent soil, due to their tendency to create air spaces between the sensor and the surrounding soil.

In order to provide an arrangement with the transfer medium that only needs to be calibrated once with the chosen sensor, the volume of transfer medium immediately surrounding the sensor is supplied to the system user as a previously mixed material or compound that is choose so that it offers a transfer medium that presents a known moisture migration. The supply of the material or compound in this way is done merely for reasons of convenience, since the ingredients can be obtained and available for use independently, or they can be mixed by the user at the place of application. It is preferred that the transfer medium includes one or more of the following ingredients:

  1) Diatomaceous earth.

  2) Fine sand.

3) Small diameter balls (for example, glass).

4) Balls or artificial granules in the appropriate way.

  5) Others (possibly small amounts of bentonite, to which other or other materials are added).

The transfer medium or a compound of two or more ingredients is preferably provided in a semi-wet state, and is placed by the user in an already prepared cylindrical container, around a cylindrical sensor. The volume of the container is, as described above, large enough to envelop the radiation influence field of the electromagnetic sensors. In this embodiment, the cylindrical vessel has approximately 20 cm radius for the particular frequencies used of 5 MHz and 150 MHz. However, the field of influence is electromagnetic and, evidently, its power is attenuated by the transfer means in different grades depending on the transfer medium. It has been experimentally established by the inventors that, at the appropriate frequency, 95% of the signal attenuation occurs in the first 4 cm radius of the transfer medium, while 99% of the attenuation is given in the first 10 cm radius of the transfer medium. Consequently, a radius of 20 cm is used in this embodiment.

The previously mixed transfer medium does not need to be compacted, although it can be lightly taped to level the upper surface. The ingredient or compound can be considered as a means of hydraulic transfer through which the moisture in the surrounding soil around the sensor arrangement flows in or out, since the humidity will move according to the various exposed forces in the above. It will take some time to establish a balance between these forces, and this will depend on the level of moisture in the soil.

Located at the top of the hole, now filled for the most part, there is a disc-shaped barrier 20. The barrier is substantially impervious to moisture and is placed in such a way that it prevents water from rain or irrigation from transferring directly from the top of the land to the transfer medium surrounding the sensor. The barrier can be made of plastic and supplied with the set of items provided to the user, or it can be made at the place of application by the user himself with a material such as, for example, bentonite.

Consequently, the hydraulic transfer medium will contain only moisture and any solutes (typically from fertilizer and other salts) that have migrated from the surrounding soil.

The fact of using a transfer medium that directly serves as an interface with the soil being tested avoids the need to use semi-permeable membranes, as was the usual practice with other devices and sensors. These membranes show osmotic effects that concentrate the liquid on one side and dilute the liquid on the other side, which adversely affects the measures being carried out.

Figure 2 illustrates two such sensors and means in an arranged coaxial arrangement, vertically separated. Elements analogous to those of Figure 1 are illustrated in Figure 2, and the upper sensor and transfer medium differ from the lower sensor and transfer medium by the suffixes a and b, respectively.

The importance of interfacial polarization effects (displacement of charges) in heterogeneous materials, such as wet soil, has been recognized as a distorting characteristic that will affect the measurement of soil moisture that employs capacitive elements at certain frequencies. It has been found that the relaxation frequency of relatively macroscopic electric dipoles associated with interfacial polarization occurs at frequencies less than 27 MHz.

Consequently, the sensor described in the aforementioned US Patent No. 5,418,466, on behalf of the same applicant, in one of its operating modes, uses frequencies widely above 27 MHz when measuring the complex dielectric constant , so that the dipole interaction does not contribute to the complex dielectric constant detected by the sensor. In another mode of operation, the sensor uses a frequency below 27 MHz.

In addition, at frequencies above 27 MHz, the complete dielectric constant detected by the sensor is fundamentally a function of the water content in the soil and, typically, also of the shape of the soil particles, their porosity and the arrangement Geometric particles.

The relationship between water content, conductivity and complex dielectric constant at frequencies below 27 MHz is a function strongly dependent on soil type, temperature and solute concentration of the soil solution.

In this way, it is possible to quantify the changes that have occurred over time in the conductivity of the soil, by measuring the complex dielectric constant at frequencies above 27 MHz (HF - high frequencies) and at frequencies below 27 MHz (LF - low frequencies). During these measurements of the soil moisture level, the sensors are in a fixed position on the floor. By maintaining two constant parameters (soil moisture and soil type), changes in the relative complex dielectric constant can be caused only by a variation in two other parameters. These variables are the conductance, as a function of the salts dissolved in the soil water per unit volume, and the temperature of the surrounding transfer medium.

There is still some speculation on the part of the inventors about whether the use of frequencies above and below 27 MHz is appropriate for all solute concentrations, particularly in high salinity environments. However, by way of example, said arrangement is used in this Report.

In this invention the described double mode frequency sensor is preferably used, although this is located within a hydraulic transfer means such that its field of influence is also contained within the volume of the transfer medium. In turn, the transfer medium is in contact with the soil to be measured, which allows, if the energy conditions are appropriate, that the soil solutions move in and out of the hydraulic transfer medium until it is reach a balance.

Calculation Stages

Referring to Figure 4, the high frequency measurement of the sensor indicates the water envelope content 1 of the hydraulic transfer medium. This does not represent the volume of water content of the surrounding soil for any given time, because the texture and volumetric capacity resulting from the storage of water from the transfer medium, for the hydraulic transfer medium, is different from the texture and to the resulting volumetric capacity of water storage of the transfer medium for the soil, at the moment in which the same measurement of matrix potential occurs in the hydraulic transfer medium and in the soil.

However, the energy level or water matrix potential in the hydraulic transfer medium is the same as the water matrix potential contained in the surrounding soil when the energy balance between these two means is reached.

The measurement of the matrix potential within the hydraulic transfer medium then reflects the soil matrix potential that the plants have to overcome in order to extract the water. This is similar, in principle, to measuring the matrix potential or negative suction within a tensometer to determine the soil matrix potential.

The functional relationship between the volume content of water <of a soil and the matrix potential of a soil, \, is described, for many types of soil, by means of specific hyperbolic soil equations that are called curves of soil water release. As a result of the almost infinite combination of soil types worldwide, many curves of soil water release remain to be determined. If a soil water release curve is known for a certain transfer medium, it is possible to determine either the volume content of water <, using the parameter \, or determine the matrix potential \ using the parameter <.

In this invention, an HF (high frequency) measurement will be used as a function determined in the laboratory for the sensor hydraulic transfer medium, using a suspended or hanging water column and a pressure plate apparatus. This solution provides the ability to establish a functional relationship between HF and \, in order to cover a range between 0 kPa and a limit yet to be determined. This limit is, at present, approximately 15 bar, as determined by the capacity of the pressure apparatus that will be used to obtain the soil water release curve.

  By keeping two parameters constant (the sensor transfer medium and the matrix potential, measured at a high frequency), changes in the negative dielectric constant can only be caused by a variation of the other two parameters.

Variable parameters are conductance, which is a function of the salt dissolved in the water of the sensor's hydraulic transfer medium (soil) per unit volume, and the temperature of the surrounding transfer medium. Both are measured, respectively, using the sensor's LF mode and an integrated temperature sensor. The osmotic potential can be ignored, since there are no semi-impermeable walls between the transfer medium and the ground.

The hydraulic transfer medium is permeable to both water and solutes. The solutes of the soil solution diffuse freely within the transfer medium, so that the water contained in the hydraulic transfer medium acquires the same composition and concentration of solute (osmotic potential) as the soil water.

Maintaining the tensor or constant matrix potential requires a correction that uses two other dimensions. Namely, the correction of the matrix potential for the gravity potential (height) and the hysteresis effects of the matrix potential in relation to the water volume content of the hydraulic transfer medium. The correction is achieved using multi-dimensional calibration models.

The inclusion of the ability to measure and take into account the matrix potential, the potential for gravity (height) and the effects of hysteresis constitutes a further development of the data analysis techniques described in US Patent No. 5,418,466. This advance allows the same type of sensor and a particular installation technique to be used in a wide variety of soil types, in order to measure the matrix potential, the volume content of water in the soil (if the curve is known of release of water from the specific soil for that soil) and the salinity of the soil solution. A multidimensional and calibrated data processing model is required, since the sensor is calibrated for a known transfer medium that reproduces in the field. This model is represented graphically in Figure 3. The flow of data processing is as follows:

Description of the data processing:

The sensor takes gross measurements at a frequency above 27 MHz (HF - high frequency), and gross measurements at a frequency below 27 MHz (LF - low frequency). The gross measurements obtained in both frequency measurements are normalized using the following equation:

Frequency at scale (SF) = (air measurement - transfer medium measurement) over (air measurement - water measurement)

Normalized high frequency values are denoted by SFH, and normalized low frequency values are denoted by SFL.

  SFH is calibrated based on the volume content of water <of the hydraulic transfer medium.

  SFH is also calibrated with the matrix potential \ of the hydraulic transfer medium (Function B), and constitutes one of the final calculated data outputs, that is, the matrix potential.

The salinity of the ECw soil solution (water salinity of the pores), as output of final calculated data, is calculated as a function of the following variables:

  one.

\ = f1 (SFH)

2.

 ECw = f2 (\, SFL)

In order to add the temperature correction to the data processing model, the temperature readings are calibrated with the volume content of water <and, hence, the HFSF (Function A) and, of this, the potential for matrix \.

The inclusion of the temperature t, which constitutes another variable in the processing model, gives rise to the following functions:

  3.

\ = f1 (SFH, t)

Four.

 ECw = f2 (\, SFL, t)

Four variables determine the salinity of the soil:

one.

 The mineralogy of the soil.

2.

 The concentration of soil solutes in the soil solution.

3.

 The potential of soil matrix.

Four.

 Soil temperature

The impact of soil mineralogy (variable 1) in the calculation of soil salinity has been excluded when using a hydraulic transfer medium. The matrix potential (variable 3) is determined using the high frequency measurement mode of the sensor and a specific soil water release curve of the hydraulic transfer medium. The concentration of solutes in the soil (variable 2) is measured using the sensor's low frequency measurement mode, and corrected for the soil matrix potential (variable 3) and the soil temperature (variable 4), to arrive at a precise concentration of solutes in the soil, which is related to an accurate measurement of the soil matrix potential.

Figure 3 shows a schematic representation of the various devices that are used for the detection and visual presentation of soil moisture and salinity parameters, such as the volume content of water in the soil and salinity.

The arrangement of the sensor and the surrounding hydraulic transfer means illustrated in Figure 1 is also shown with reference 30 in Figure 3. The sensor is the source of signals generated by the sensor apparatus (16, 18) in the two modes of functioning. In this embodiment, the described sensor has two modes, although other sensors may not need to work that way. The data generated by the sensor is sent to a data processing device 40, which, in this embodiment, is a data recording device. Data logging devices are well known in the field of use of remote sensors, and do not need to be described in detail here. In this embodiment, the type of data processing required is described in US Patent No. 5,418,466. It is noteworthy, however, that the required processing could be carried out at the same sensor location, or it could be performed at a remote location, such as by means of a computer installed in the user's residence or office. The processing could be carried out on the fly, or it could be carried out in preparation for the generation of the graphic output that is made available to the final user of the arrangement. If some remote processing is done, then there are many known methods for communicating the data to the distant location.

An essential value for the user of the arrangement is the provision of trend information, provided in the form of a graph, of which an example is given in Figure 4.

Figure 4 illustrates an example of a graph that an end user will use to make decisions regarding irrigation control and fertilization.

The graph illustrates parameter 1 as the soil water content and parameter 2 as soil salinity, plotted as a function of a common time on an axis 3.

The units of the water content in the soil are provided in mm of soil water per 100 mm of depth of the hydraulic transfer medium. Alternatively, it is possible to transform the units into a matrix potential using the specific soil water release curve for the hydraulic transfer medium. The exact scale has been omitted, as it varies with the type of hydraulic transfer medium.

Units 2 of soil salinity can be presented as dS / m (deci-Siemens per meter). It is also possible to express them as! S · cm-1 (micro-Siemens per centimeter) and as ppm (parts per million total dissolved solids). 1 dS · m-1 = 100 EC (Electrical Conductivity measured in! S · cm-1) = 640 ppm. The exact scale has been omitted, since it varies with the type of hydraulic transfer medium.

The unit of time axis 3 is shown as hours and days. Time can also be expressed as seconds, minutes, days, weeks, months or years.

Multiple irrigation events 4a to 4f are plotted using the water content axis 1 in the soil and the time axis 3.

  Multiple levels of resulting salinity are plotted 5a to 5g (after each irrigation event), using the soil salinity axis 2 and time axis 3.

The soil salinity level, 5th, on October 31 before 12:00 p.m. it was very low, with a value of 0.1 dS · m-1 (the salinity of rainwater), and was used as a lower baseline 6 for salinity, with respect to which it is possible to measure the increments and Salinity drops.

The soil salinity threshold 7 is specific to each crop and indicates the average salinity in the root zone for which salts begin to affect crop or pasture growth. Beyond this value, the decrease in crop yield can be expected. In this example, the soil salinity threshold has been set at 1.5 dS · m-1, which is the critical threshold for white clover.

  Other important soil salinity thresholds (not shown here) may indicate 25%, 50% and 75% of the yield loss threshold for a particular crop. For example, a soil salinity threshold of 3.6 dS · m-1 indicates 25% of the yield loss threshold for white clover.

Irrigation 4a applied shortly after 12:00 on October 31 contained a salt measurement of 5.8 dS · m-1, and created a 5b level of 5.8 dS · m-1. This level of soil salinity is seriously detrimental to most agricultural crops.

Irrigation 4b on November 1 was applied as a leaching irrigation that was used as distilled water to wash all salts from the soil by washing. This irrigation 4b caused an abrupt drop in salinity that stabilized at a level 5c on November 2, which was close to the base salinity level 7.

Irrigation 4c applied on November 2 contained a salinity level of 1.0 dS · m-1, and caused only a very slight increase in the level, to give a resulting level 5d.

The 4d irrigation applied on November 3 contained a salinity of 2.2 dS · m-1, which increased the salinity level 5e above the critical soil salinity threshold 7 for white clover.

Irrigation 4e, with a salinity of 3.0 dS · m-1, applied on November 4, continued to increase the level of salinity to level 5f.

On November 5 another leaching irrigation event 4f was applied using distilled water, which caused the soil salinity level to drop to a value 5g below the critical soil salinity threshold 7, and continued to decrease to stabilize in a level just slightly above the base 6 salinity level.

The graphic representation provided in Figure 4 allows the user to appreciate the interaction between soil moisture and soil salinity simultaneously and almost continuously for a particular depth level of the soil profile, when multiple sensor arrangements placed are used. in vertical alignment, separated from each other and on the same axis, as illustrated in Figure 2.

Figure 5 shows a variety of forms of the hydraulic transfer means in which a capacitive sensor can be arranged embedded, so that its sphere of influence is substantially contained within the hydraulic transfer means.

The shapes illustrated in Figure 5 are generic. It is considered that the principle of the invention has been adequately described in this Report. Consequently, the choice of the actual form to be used in most situations will probably correspond to the generic forms illustrated. Alternatively, the form may consist of a combination of one or more of these or variations thereof, or in a completely different way. The examples provided are not intended to constitute limitations of the scope of the invention.

The following is a brief explanation of the forms that are suitable for different measurement applications:

1) A square shape on the soil surface can be used to determine the conditions of moisture and surface salinity. A rectangular hole is drilled in the ground, so that the sensor can be embedded in the transfer medium or mounted on a flat plastic surface that forms a cover over the shaped hydraulic transfer medium (HMM - “Hydraulic Migration Medium”) .

2) A triangular shape can be used with the direct placement of the hydraulic transfer medium on the floor surface, in order to make the device more sensitive to the conditions of humidity and salinity of the soil surface. A plastic cover, which takes the form of a roof, in this example, the shape of a roof, will cover the HMM. The sensor may be arranged embedded in the HMM or mounted on the roofing material, located internally to the shape. Water that slides and falls from the roof will move to the sides of the measuring device and penetrate the ground, so that it can also be measured.

3) A cylindrical shape is used when making a hole in the ground and filling it with HMM. The sensor is coaxially positioned with the cylindrical shape of the HMM.

4) A solid or solid ring form is used for the HMM within a pottery container, in which the hole of the HMM ring is filled with a growth medium (perlite, pumice - pumice stone -, pottery mix, etc.). The arrangement of the capacitive elements (not shown here) can be found, either on the outside of the solid ring shape, or be located both inside and outside the shape.

5) The insertion of a metal tip into the floor surface and its filling with the HMM creates the shape of a funnel. The sensor can be placed inside the HMM or placed in a portable tracking device that will be placed on top of the HMM funnel.

6, 8, 9) Soaking the soil to create interception channels in order to control the possible paths of water flow and salinity in the soil profile and in the soil will be a reason to create and use the forms 6 , 8 and 9.

7) Form 7 is, like form 3, cylindrical, although the arrangement of the sensor plates (not shown) is carried out on the outside of the cylinder. This arrangement is useful if the HMM is contained in a tube that is in hydraulic contact with the soil to be measured, assuming that the sensor plates 16 can be arranged so as to allow relatively unimpeded migration or transfer of moisture. of the surrounding soil inside and outside the HMM.

Figure 6 illustrates a variety of sensor shapes that show how different sensors can be used in different ways for the same and different HMM configurations. As a capacitive or capacitor sensor is used in these examples, there must be at least two conductive elements. As can be seen, the elements can be in the form of wire, strips or bands, or plates, and other arrangements for the capacitive elements are possible. In Figure 6, one of the portions of the two-part sensor is shown in a continuous line, and the other portion is shown in a broken line.

The elements can be arranged in such a way that the HMM substantially encloses or substantially encompasses the radiation field (electromagnetic radiation (EM - “Electromagnetic radiation”)) between the elements, and thus forms the dielectric, which will be affected by moisture and salinity of the soil that travels within it, as a result of the balance or energy stabilization that is established between the HMM and the surrounding soil. However, in some cases, only a portion of the electromagnetic radiation generated will be confined within the volume of the HMM. The remaining electromagnetic radiation, in these applications, must be arranged so that it is released into the air or contained within a material inert to salinity and moisture, and, in any case, a known medium that is a material that do not absorb water or salinity, such as air, plastic, ceramic materials, etc.

It will be appreciated by those skilled in the art that the invention is not restricted in use to the particular application described. Nor is the present invention restricted to its preferred embodiment as regards the particular elements and / or features described or illustrated herein. It will be appreciated that various modifications can be made without departing from the principles of the invention. Accordingly, it will be construed that the invention includes all these modifications within its scope.

Claims (11)

1. An arrangement for the measurement of soil parameters, comprising: a container permeable or transparent to electromagnetic energy a capacitive base soil moisture sensor located within a predetermined means of moisture transfer, the predetermined moisture transfer medium, located so that the soil moisture to be measured can be transferred to the predetermined transfer medium, and said sensor measures at frequencies above 27 MHz the complex dielectric constant of the transfer medium by deducting the soil moisture, the volume content of the soil water and the potential of the transfer medium using a soil water release curve based on the hydraulic transfer medium, The sensor measures at frequencies below 27 MHz the complex dielectric constant of the transfer medium by deducting the solute concentration from the soil solution.

2.

Arrangement for measuring soil characteristics according to claim 1, wherein the container is filled with the predetermined moisture transfer medium and the capacitive base soil moisture sensor is located within the predetermined transfer medium.

3.

Arrangement for measuring soil parameters according to claim 1, wherein an empty volume is formed in the predetermined transfer medium, and filled with the soil to be measured.

Four.

Arrangement for measuring soil parameters according to claims 2 and 3, wherein an oscillator oscillates within two different frequency bands one above and another below 27 MHz, and varies in these bands depending on the dielectric constant of the Default means of transfer.

5, Arrangement for the measurement of soil parameters according to claim 1, wherein said predetermined means of transfer contains diatomaceous earth or a fine sand, either small glass beads or an artificial material, or compounds formed with the same.

6.

Arrangement for measuring soil parameters according to claim 2 or 3, further comprising a barrier substantially impermeable to moisture, located above said moisture transfer means.

7.

Arrangement for the measurement of soil parameters, according to claim 2 or 3, in which two or more of said sensors have been placed in an orderly arrangement, separated from each other at a predetermined distance, and said ordered arrangement has been oriented vertically with said transfer means, so that both said arranged arrangement and said transfer means are located on said floor so that said measurements provide a floor profile.

8.

A method for measuring soil parameters, which includes the steps of:

a) placing a capacitive base soil moisture sensor inside a container filled with a predetermined means of moisture transfer, so that the soil moisture to be measured can be transferred to said transfer medium; said sensor measures at frequencies above 27 MHz the complex dielectric constant of the transfer medium by deducting soil moisture, the volume content of the soil water and the potential of the transfer medium using a soil water release curve as a function of the hydraulic transfer medium b) measure the complex dielectric constant of the transfer medium at frequencies below 27 MHz by deducting the solute concentration from the soil solution 9. Method for measuring soil parameters according to claim 8, comprising the additional step of: c) forming an empty volume in said soil to be measured, and filling it with said predetermined means of transfer and a sensor.

10.

Method for measuring soil parameters, according to claim 8, comprising the additional step of:

eleven.

Method for measuring soil parameters according to claim 8, in which two or more of said sensors are placed in an ordered arrangement, separated by a predetermined distance from each other, and said arranged arrangement is oriented vertically with said means of transfer, so that both said arranged arrangement and said transfer means are located on said floor such that said measurements provide a soil profile.

d) forming a barrier substantially impermeable to moisture above said moisture transfer means. SPANISH OFFICE OF THE PATENTS AND BRAND Application no .: 201030852 SPAIN Date of submission of the application: 16.09.2010 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE 51 Int. Cl.: G01N27 / 22 (2006.01) G01N33 / 24 (2006.01) RELEVANT DOCUMENTS

Category

56 Documents cited Claims Affected

X

EN 2276553 A1 (SENTEK PTY LTD) 16.06.2007, the whole document. 1-11

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the date of priority submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims • for claims no:

Date of realization of the report 07.02.2013

Examiner A. Figuera González Page 1/5

REPORT OF THE STATE OF THE TECHNIQUE Application number: 201030852 Minimum documentation sought (classification system followed by classification symbols) G01N Electronic databases consulted during the search (name of the database and, if possible, terms of search used) INVENES State of the Art Report Page 2/5  WRITTEN OPINION Application number: 201030852 Date of Completion of Written Opinion: 07.02.2013 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims Claims 1-11 IF NOT

Inventive activity (Art. 8.1 LP11 / 1986)

Claims Claims 1-11 IF NOT

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/5  WRITTEN OPINION Application number: 201030852  1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

ES 2276553 A1 (SENTEK PTY LTD) 06/16/2007

 2. Statement motivated according to articles 29.6 and 29.7 of the Regulations for the execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement CLAIM 1 Document D01 describes an arrangement for measuring soil parameters comprising a capacitive base soil moisture sensor and a transfer means arranged in such a way that moisture can be communicated or transferred with the soil to be measured. . The sensor measures the complex dielectric constant of the medium comprising calculation means to deduce soil moisture. See D01, claim 1. On the other hand, the use of two sensor operating modes is also described in document D01. In one of the modes the sensor operates at frequencies well above 27 MHz in which the variation in salinity results in a negligible effect and the output depends primarily on soil moisture. For frequency operation widely below 27 MHz, the frequency depends not only on changes in soil moisture but also depends, in part, on changes in salinity. Simplifying, if the response obtained in the first mode is based on the response obtained in the second mode, then the result would be an indication of the salinity of the soil. See D01, page 9, lines 13 to 23. In addition, document D01 mentions the use of a container permeable or transparent to electromagnetic energy for the same purpose as the container mentioned in claim 1. See D01, page 8, lines 10 to 14. Finally, in document D01, the calculation of the volume content of the soil water and the water matrix potential in the hydraulic migration material using soil water release curves is described. See D01, page 9, line 57 to page 12, line 35. Thus, document D01 discloses all the elements of claim 1. In conclusion, claim 1 is novel in accordance with article 6 of Patent Law 11/1986. CLAIMS 2 to 4 Claims 2 to 4 refer to technical characteristics already disclosed in document D01 as indicated below. Therefore claims 2 to 4, depending on claims that are not new, in turn lack novelty.

Reiv. 2:

 Figure 1 illustrates a sensor 10 located in a single / composite coil installation 12 which in turn is located on the floor 14 whose moisture and salinity content characteristics are to be measured.

Reiv. 3:

 On page 8, lines 10 to 14 an embodiment is contemplated in which the soil to be measured is within a volume contained in the migration medium.

Reiv. 4:

In document D01, it is indicated that the oscillator oscillates within two different frequency bands (above and below 27 MHz) and varies in these bands depending on the dielectric constant of the material in the vicinity of the rings (see D01, page 9, lines 13 to 16).

CLAIM 8 Document D01 also describes a method for measuring soil parameters that comprises two stages: a) placing a capacitive or condenser-based soil moisture sensor in a migration or moisture transfer medium and b) measuring the constant complex dielectric of the medium in order to deduce the volume content of water from said medium using said sensor, and process said measurement to determine the matrix or tensor potential of said soil. See D01, claim 6. There are aspects of claim 8 of the application that are not reflected in claim 8 of D01, but these aspects are described in the description. See D01, page 9, lines 13 to 23, page 8, lines 10 to 14 and page 9, line 57 to page 12, line 35. Thus, document D01 discloses all the elements of claim 8 and therefore claim 8 is not new. State of the Art Report Page 4/5  WRITTEN OPINION Application number: 201030852 CLAIMS 5 to 7 and 9 to 11 Claims 5 to 7 and 9 to 11 of the application respectively have the same wording as claims 3 to 7 and 8 to 10 of document D01. Thus, they do not provide any additional technical characteristics that have not already been disclosed in document D01. In conclusion, claims 5 to 7 and 9 to 11, which depend on previous claims that lack novelty, in turn, lack novelty. State of the Art Report Page 5/5