Measurement apparatus for and measurement method of performing subterranean measurements

Abstract

A measurement apparatus (4) for performing subterranean measurements comprises at least one measuring structure (2) comprising at least one microwave sensor (102) for performing the subterranean measurements. The measuring structure (2) digs into the ground and moves inside a cut (600) of the soil (10) while said measurement apparatus (4) moves on the ground, and each of the at least one measuring structure (2) is configured to move in contact with the soil (10) within the cut (600). The at least one microwave sensor (102) measures at and / or below the ground level (12) on one or more sides of the cut (600) repeatedly when moving inside the cut (600).

Description

[0001] Measurement apparatus for and measurement method of performing subterranean measurements

[0002] Field

[0003] The invention relates to a measurement apparatus for and a measurement method of performing subterranean measurements.

[0004] Background

[0005] Subterranean measurements can be performed using a rod embedded in the ground at one end. The part of the rod has at least one sensor such as an impedance sensor and / or a microwave sensor. The sensor may measure moisture, for example. When properties of a larger field are wished to be measured, that is technically challenging. These measurements are performed at certain points, and they represent only a small area. The structure penetrating through the surface of the ground may guide rain to the measurement point which may cause the measurement to overestimate particularly the moisture percentage. Large numbers of rods with sensors are needed. Their spreading over the field(s) takes time and requires working power. How to power the separate sensors that may be far away from each other and gather the information from them is also technically challenging. Additionally, the probability that some sensors fail to function properly increases with increasing number of the rods with the sensors.

[0006] A technical solution to overcome these problems has been to embed an unshielded microwave transmission line in the ground where the microwave signal is delayed in proportion to the dielectric constant of the soil. To embed the cable in the soil and take it back from there is cumbersome and may damage the cable. Roots and some animals may break or cause harm to the cable.

[0007] To avoid these challenges, the surface of the ground has been measured remotely based on reflection of the microwave radiation. This technical solution suffers from disturbances caused by roughness of the surface of the ground and plants. Additionally, the measurement concentrates on the air-soil interface while the properties deeper in the soil cannot be measured. Hence, improvement would be welcome.Brief description

[0008] The present invention seeks to provide an improvement in the measurements.

[0009] The invention is defined by the independent claims. Embodiments are defined in the dependent claims.

[0010] If one or more of the embodiments is considered not to fall under the scope of the independent claims, such an embodiment is or such embodiments are still useful for understanding features of the invention.

[0011] List of drawings

[0012] Example embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which Figures 1 and 2 illustrate examples of a measurement apparatus for performing subterranean measurements;

[0013] Figures 3 and 4 illustrate examples of a measuring structure that is like a blade, a plate or a bar;

[0014] Figure 5 illustrates an example of a pair of a measuring structure that is like a bar and a cutting blade that is a disc;

[0015] Figure 6 illustrates an example of a measuring structure resembling a bar that follows a cutting blade that makes a cut in the soil;

[0016] Figure 7 illustrates an example of a measuring structure that is a disc and has near-field sensor having field on both sides or two microwave sensors on opposite sides of the measuring structures that are blades;

[0017] Figure 8 illustrates an example of two measuring structures that are blades between which the measurement of at least one property of the soil is performed;

[0018] Figure 9 illustrates an example of the measuring structure of a disc form, the measuring structure having means for converting kinetic energy into electrical form;Figure 10 illustrates an example where a reflector is used to measure the at least one property of the soil;

[0019] Figure 11A illustrates an example where the measuring structures are bars extending radially outwards from a shaft;

[0020] Figure 11B illustrates an example of Fig. 11A from behind in direction of the movement of the measurement apparatus;

[0021] Figure 11C illustrates an example of a measurement bar that is forced into the ground and pulled back from the ground repeatedly;

[0022] Figure 11D illustrates an example of measurement bars that are forced into the ground and pulled back from the ground repeatedly;

[0023] Figure 12 illustrates an example where a motorized vehicle pulls the measurement apparatus;

[0024] Figure 13 illustrates an example where the measurement apparatus is motorized;

[0025] Figure 14 illustrates an example where a drag coulter that includes a microwave sensor creates a furrow;

[0026] Figure 15 illustrates an example of a seeder that has a tube system and a disc coulter;

[0027] Figure 16 illustrates an example of a disc coulter;

[0028] Figure 17 illustrates an example of a series coupling of microwave sensors;

[0029] Figure 18 illustrates an example of an accurate attenuation measurement of soil;

[0030] Figure 19 illustrates an example of a data processing unit; Figures 20A and 20B illustrate examples of an irrigation system that can be controlled as a function of location based on the measurement of the at least one property of the soil; and

[0031] Figure 21 illustrates of an example of a flow chart of a measuring method and an irrigation control method.

[0032] Description of embodimentsThe following embodiments are only examples. Although the specification may refer to “an” embodiment in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment.

[0033] Single features of different embodiments may also be combined to provide other embodiments. Furthermore, words "comprising" and "including" should be understood as not limiting the described embodiments to consist of only those features that have been mentioned and such embodiments may also contain features / structures that have not been specifically mentioned. All combinations of the embodiments are considered possible if their combination does not lead to a structural or logical contradiction.

[0034] The subterranean measurement in this document can be defined such that the at least one sensor 102 is and performs at least temporally the measurements below the surface of the ground or the earth. The subterranean measurement may also be called subterraneous or subterrestrial measurement.

[0035] A microwave sensor 102 means in this document a component that transmits and receives microwave radiation, which in this document is made to travel through the soil 10 before the reception. The microwave sensor thus refers to a transmitter and a receiver of the microwave radiation. The microwave sensor 102 detects one or more parameters of the received microwave signal. The one or more parameters may refer to attenuation, a phase shift, Q- value and / or a delay. The Q- value is a quality factor that is a dimensionless parameter that describes how selective a resonant system is with respect to frequencies. The transmitter and receiver may be integrated together, or they may be separate components with a physical distance. The difference or variation of the received signal with respect to the transmitted signal or a reference signal enables formation of information on properties of the soil 10. A person skilled in the art is familiar with microwave measurements, perse.

[0036] Fig. 1 illustrates an example of a measurement apparatus 4 for performing subterranean measurements. The measurement apparatus 4 moves along the ground and comprises at least one measuring structure 2 that digs intothe ground. The measuring structure 2 can be called a bar or a blade in examples of Figs 1 to 10. Because those names describe the measurement structure 2, said names have been used in Figs 1 to 10 for the measurement structures 2 with reference numbers relating to 100. The blade in these Figs is made to dig into the ground and moves laterally at least partly below the ground level 12 within soil 10. The lateral movement refers to a direction of the movement of the measurement apparatus 4, and movement is orthogonal to the direction of gravitation which can be considered vertical. The at least one measuring blade 100 comprises at least one microwave sensor 102 for measuring the soil 10. The ground level 12 means the surface of the earth at the location where the measurement is performed.

[0037] An edge 300 of the at least one measuring blade 100, which is illustrated in Figs 4, 7, 8, 9 and 10, may, in an embodiment, form a cut 600 in the soil 10 (the cut is illustrated in Fig. 6). In an embodiment, the cutting is additionally or alternatively performed by a separate cutting blade 302, 500, see Figs 3, 5 and 6. The measuring blade 100 is then traveling inside the cut 600 of the soil 10. The at least one measuring blade 100 or the cutting blade 302 as if plows the soil 10 but the soil 10 is merely cut by the measuring blade 100 without turning the soil 10. The cut 600 can also be considered a furrow.

[0038] Said at least one measuring blade 100 is moving in a direction orthogonal to a normal N of surfaces of the faces of the blade 100. At least a part of each of the at least one measuring blade 100 is in contact with the soil 10 within the cut 600 while moving through the soil 10. That means, the flat surfaces of the measuring blade 100 are then against the soil 10 of the cut 600 which also enables the at least one microwave sensor 102 to be in contact with the soil 10.

[0039] The at least one microwave sensor 102 measures repeatedly at and / or below the ground level 12 on one or more sides of the measuring blade 100 and the cut 600 while it is moving inside the cut 600. Figs 1, 4 and 7 illustrate the example where the microwave sensors 102 are and / or measure on two sides of the measuring blade 100.In an embodiment, a data processing unit 108 may determine at least one property of the soil 10 at a plurality of locations based on the measurements of the at least one microwave sensor 102.

[0040] In an embodiment, the at least one microwave sensor 102 may comprise a ceramic microwave sensor that may utilize one or more ceramic materials for transmitting and receiving the microwave radiation. Ceramic materials are wear-resistant to corrosion and abrasion in a harsh environment. The microwave sensors are widely used in various engineering applications, and a person skilled in the art is familiar with the microwave sensors, perse.

[0041] The at least one measuring blade 100 can be defined to be a flat and thin structure like a plate. The blade 100 may be sharp-edged. In an embodiment, the sharp edge which may be called a cutting edge 300 may be configured to cut the soil 10 (see Figs 4 and 9). Alternatively, the measuring blade 100 may travel inside a ready-made cut 600, and then the cutting edge 300 may be unnecessary. The measuring blade 100 may be made from metal, such as steel, alloy or other wear resistant materials. The measuring blade 100 can thus effectively endure the wear caused by the movement inside the soil 10. The durable material can extend the lifespan and reliability of the measuring blade 100. All in all, the measuring blade 100 with the at least one sensor 102 may be designed to cut the soil 10 or pass through a premade cut 600.

[0042] As shown in Figs 1, 2, 7, 8 and 9, the at least one measuring blade 100 may be mechanically and electrically connected with a support structure 104 that can imbed the blade 100 into a desired depth inside the soil 10. The support structure 104 may be a part of the measurement apparatus 4 for performing the subterranean measurements. In an embodiment, the depth of the at least one microwave sensor 102 may be adjusted. In an embodiment, the depth of the at least one microwave sensor 102 may be varied regularly or irregularly while the measurement apparatus 4 is moving.

[0043] Fig. 1 additionally illustrates a microwave electronic circuit 106 that generates the microwave radiation. The generated microwave radiation is guided and / or conducted to the at least one microwave sensor 102. The microwaveradiation that is received by the microwave sensor 102 is guided and / or conducted to the microwave electronic circuit 106. The microwave radiation may be conducted between the microwave sensor 102 and the microwave electronic circuit 106 through a coaxial cable, for example. The microwave radiation may be conducted between the microwave sensor 102 and the microwave electronic circuit 106 through a waveguide, for example. A person skilled in the art is familiar with how to generate and guide / conduct microwave radiation, per se.

[0044] In an embodiment an example of which is illustrated in Fig. 2, the support structure 104 may comprise a frame structure 200. The frame structure 200 and the at least one measurement blade 100 are attached together. The support structure 104 may also comprise an adjustment apparatus 202 that may raise and lower the frame structure 200 which then make the at least one measuring blade 100 go up or down within the soil 10. Fig. 2 also illustrates an example of the measurement apparatus 4 that may comprise the support structure 104 and movement mechanics 204 connected with the adjustment apparatus 202. The movement mechanics 204 may have tires 206 or the like which enable the measurement apparatus 4 to move. A person skilled in the art is familiar with movement mechanics, per se. The movement mechanics may utilize electromechanics such as electric motors, chains and gears, for example. Additionally or alternatively, pneumatic and / or hydraulic systems may be utilized.

[0045] In an embodiment an example of which is illustrated in Figs 1, 7 and 8, the at least one microwave sensor 102 may comprise a resonator whose resonance frequency depends on properties of the soil 10 which the resonator is in contact with. This kind of measurement may be performed by a near-field microwave sensor 102 that is designed to detect electromagnetic fields in proximity, i.e. in the near field 114, see ellipses in Figs 1, 6, 7, 8 or 14. A person skilled in the art is familiar with near-field sensor, perse. The maximum distance of the near field 114 that the near-field microwave sensor can detect may be considered about the width of the sensor. That means the near field 114 may extend some centimeters at microwave frequencies. Within the soil 10, the maximum distance of the near field depends on the dielectric properties of the soil. The microwave sensor 102 detectsthe alteration of the electromagnetic field by the variation of the moisture percentage enabling the data processing unit 108 to perform moisture percentage determination, for example, based on the measurement performed by the at least one microwave sensor 102. Another possibility is the measurement of density or porosity of the soil 10, for example.

[0046] In an embodiment an example of which is illustrated in Fig. 3, at least one of the at least one measuring blade 100 is non-rotatable. Any non-rotatable measuring blade 100 may pushed, pulled or forced through the soil 10 for forming the cut 600 in a manner a knife cuts an object. Alternatively, any measuring blade 100 may be guided to travel through a ready-made cut 600 in the soil 10.

[0047] In an embodiment an example of which is illustrated in Fig. 3, the measurement apparatus 4 may comprise at least one cutting blade 302 which may be a a plate. In an embodiment an example of which is illustrated in Fig. 5, the measurement apparatus 4 may comprise at least one cutting blade 302 that may be a cutting disc 500. The cutting blade 300 and the cutting disc 500 may be separate from the measuring blade 100 although the cutting blade 302 in the form of a bar may be integrated with the measuring blade 100 (see Fig. 3). The cutting blade 302 or the disc 500 is in front of the measuring blade 100 in the direction of the movement of the measurement apparatus 4. The cutting blade 302 and the measuring blade 100 may form a pair. Correspondingly, the cutting disc 500 and the measuring blade 100 may form a pair. Then, the cutting blade 302 or the cutting disc 500 forms the cut 600 in the soil 10 and the measuring blade 100 travels at least partly inside the cut 600 when performing the microwave measurements.

[0048] The cutting blade 302 that resembles a bar has a sharp and vertical edge 304 that cuts through the soil 10 ahead of the measuring blade 100 as shown in Fig.

[0049] 3. The vertical edge 304 may include a cutting blade point 306 that makes contact with the soil 10. It may be designed to penetrate and slice through the ground efficiently. This helps create a clean cut 600 by cutting through the soil 10 and any potential plant material on the surface and inside the soil 10. The cutting blade 302 makes it easier for the measuring blade 100 to move within the soil 10 efficiently.Correspondingly, the cutting disc 500 shown in Fig. 5 has a sharp edge 502 that may cut through the soil 10 ahead of the measuring blade 100 while the cutting disc 500 is rotating around its central axis CDCA. This helps create a clean cut 600 by cutting through the soil and any potential plant material on the surface and inside the soil 10. The cutting disc 500 makes it easier for the measuring blade 100 to move within the soil 10 efficiently.

[0050] Each of the at least one cutting blade 300 and / or the cutting disk 500 may cut 600 the soil 10 without removing material of the soil 10 from the cut 600. In that manner, when the measuring blade 100 is pulled, pushed or forced into the cut 600, the material of the soil 10 will be in contact with the surface of the measuring blade 100 and the at least one microwave sensor 102 that is at the surface of the measuring blade 100.

[0051] Fig. 6 illustrates an example where the cutting blade 302, which is the cutting disc 500 in this example, forms the cut 600 in the soil while it is moving, and the measuring blade 100 follows behind the cutting blade 302 and travels at least partly inside the ready-made cut 600. In Fig.6, the microwave sensor has been illustrated to measure the near field 114, which is an example. An additional example in Fig. 6 shows that the microwave sensor 102 transmits microwave radiation (see the zigag arrowhead) toward a receiving microwave sensor or a reflector, which are not shown in Fig. 6.

[0052] In an embodiment an example of which is illustrated in Figs 7 and 9, at least one measuring blade 100 has the shape of a disc and then it may be called a measuring disc. The at least one measuring blade 100 that has the shape of a disc may rotate around its central axis CA in order to form the cut 600 in the soil 10. The measuring blade 100 may travel inside the cut 600 of the soil 10 without removing material of the soil 10 from the cut 600 for making the vertical surfaces of the cut 600 to be in contact with each other. In Fig. 9, the microwave sensors parts 102(1) and 102(2) of the microwave sensor 102 measure in this embodiment on two sides of the measuring blade 100. In Fig. 7, the microwave sensor has been illustrated to measure the near field 114, which is an example.In an embodiment an example of which is illustrated in Fig. 8, the measurement apparatus comprises at least one pair of the measuring blades 100(1), 100(2) at a non-zero distance D from each other. Both measuring blades 100(1) and 100(2) travel inside their own cut 600. The distance D, that is also the distance of the cuts 600, may be about 1 cm to about 50 cm, for example. The microwave sensor parts 102(1), 102(2), which are a microwave transmitter and a microwave receiver, belong to different measuring blades 100(1), 100(2) of said at least one pair and they may transmit a microwave signal through the soil 10 between the measuring blades 100(1), 100(2) of said at least one pair for measuring at least one property of the soil 10 within the distance D, see the doubleheaded zig-zag arrow. Also in this embodiment, at least one of the microwave sensors 102(5) may measure the soil 10 on the side opposite to the microwave sensor parts 102(1), 102(2). Also the material of the soil 10 that is not between the measuring blades 100(1), 100(2) may thus be measured, see the dashed ellipse that represents the near-field 114.

[0053] In an embodiment as shown in Fig. 8, there may be another pair of microwave sensor parts 102(3), 102(4) (transmitter and receiver). They may measure the soil 10 therebetween in a manner similar to the microwave sensor parts 102(1), 102(2). Additionally or alternatively, the microwave sensor parts 102(1), 102(2), 102(3) and 102(4) may cross-transmit or transmit diagonally instead of or in addition to direct transmission (see the double-headed zig-zag arrows). The number of pairs of microwave sensor parts is not limited to two. In case of rotating disc, the cross-transmission signals are not needed because they do not give more information.

[0054] As shown in Fig. 9, the at least one microwave sensor parts 102(1), 102(2), 102(3) is in all depths inside the soil between the range 0 to maximum depth MD when the disc formed measuring blade 100 is rotating while moving forward. In that manner, different layers of soil 10 may be measured and mapped. The trace of each microwave sensor 102 may be a cycloid and a part of the cycloid path is within the soil 10 when the measuring blade 100 is rotating forward without slipping.In an embodiment an example of which is illustrated in Fig. 10, the measurement apparatus 4 comprises at least one pair of the measuring blades 100(1), 100(2) at a non-zero distance D from each other. One blade 100(1) of said one pair of the measuring blades 100 comprises at least one microwave sensor 102. The other blade 100(2) of said pair of the measuring blades 100(1), 100(2) comprises a reflector 1000. The at least one microwave sensor 102 may transmit microwave signal through the soil 10 toward the reflector 1000 that may reflect the microwave communication back to the at least one microwave sensor 102. In that manner, the microwave radiation travels two times the distance D between the blades. The reflector 1000 may comprise a metal blade or the reflector 1000 may be a blade that is fully or partially covered with metal. The reflector 1000 may be a rotating disc or a non-rotating bar or plate. In this arrangement the transmitting and receiving sensors can be installed separately side by side to get better isolation between them.

[0055] Note that the measuring blade(s) 102 may be tilted from a vertical direction. That means, the normal N of the measuring blade(s) 102 is not orthogonal with respect to the vertical direction. Then, also the cut(s) 600 have a corresponding tilt. The tilt may improve contact between the soil 10 and the at least one microwave sensor 102 and reduce the number of reflections and a multipath propagation.

[0056] In an embodiment an example of which is illustrated in Fig. 12, the measurement apparatus 4 may be pulled by a motorized vehicle 1200 such as a tractor, for example. The measurement depth of the at least one microwave sensor 102 may be controlled by the motorized vehicle 1200. Alternatively, the measurement apparatus 4 may have a mechanism for adjusting the depth.

[0057] In an embodiment an example of which is illustrated in Fig. 13, the measurement apparatus 4 may alternatively be a motorized vehicle. When it moves, it may be an unmanned self-driven vehicle or a manned vehicle such that a person drives it.

[0058] In an embodiment an embodiment of which is illustrated in Fig.9, the at least one microwave sensor 102 receives its electrical power from the rotation ofthe at least one measuring blade 100. An electric generator 900 may be attached between the measuring blade 100 and its shaft 904. When the measuring blade 100 rotates, the generator 900 generates electric energy which it can feed to an electronic circuit of the at least one sensor 100 through conductors 902. The generator 900 may include the needed electric circuits for feeding the electric energy in a suitable form to the at least one microwave sensor 102. In a corresponding manner, the at least one microwave sensor 102 may receive its electric power from the at least one cutting blade 500 and / or the reflector 1000 that is a rotating disc. By that way the electronics can be integrated in the rotating cutting blade.

[0059] Fig. 9 illustrates also an embodiment where the rotating measuring blade 100 may include integrated microwave electronics and a wireless transmitter 906. The wireless transmitter 906 may transmit the measurement signal coming from the at least one microwave sensor parts 102(1) to 102(3) of the microwave sensor 102 to a receiver that is in the environment. The receiver may be a separate receiver from the microwave electronic circuit 106 that forwards the measurement information to further processing and / or to a data storage. The at least one microwave sensor 102(2) to 102(3) and / or the wireless transmitter 906 may have memory to store the measurement signal information for a certain period. The wireless transmitter 906 may transmit measurement data when the wireless transmitter 906 is above the ground but may refrain from transmitting while the transmitter 906 is under the ground within the soil 10. The wireless transmitter 906 may have the information whether it is above or below the ground 12 from an angular position of the measuring disc 100, and based on that information, the wireless transmitter 906 can transmit when it is above the ground. The wireless transmitter 906 may comprise a radio frequency transmitter or an ultrasound transmitter.

[0060] Alternatively, the measuring blade 100 of a disc or blade form may have oscillation mechanism that transforms kinetic energy into electrical energy based on an oscillating weight, for example. The oscillating weight may be a rotor that receives the kinetic energy of the vibrational movements of the measuring blade100. An electric generator then transforms the kinetic energy into an electric form through electromagnetic induction. This kind of oscillation system may be corresponding to those in watches, for example. A person skilled in the art is familiar with mechanisms that transform kinetic energy into the electric form, per se.

[0061] In an embodiment, the oscillation mechanism may generate electric energy from the kinetic energy of up and down and sideway vibration of the at least one measuring blade 100 to the at least one microwave sensor 102 of said at least one measuring blade 100 while it is moving and potentially cutting the soil 10.

[0062] Fig. 11A illustrates an example where the measuring structures 2 are measurement bars 100 extending radially outwards from a shaft 1100 which is configured to rotate during operation. The measurement bars 100 penetrate the soil 10 repeatedly, move vertically inside the soil 10 and form cuts 600 in the vertical direction. Fig. 11A shows the cuts 600 behind measuring structures 100 that have also moved along the ground as a part of the measurement apparatus 4. The movement along the ground can be considered lateral movement. The measurement bars 100 have formed the vertical cuts 600 in the soil 10, and the measurement bars 100 have moved in the cut 600 down and up. When forming the cut 600 and moving within it, the at least one microwave sensor 102 of the measurement bars 100 measures the soil 10 during movement at one mor more depths in the similar manner to what taught in Fig. 8 or 10, for example although the movement inside the cut 600 is vertical in this example.

[0063] Fig. 11B illustrates an example of Fig. 11A from behind in direction of the movement of the measurement apparatus. In this example, there are two measuring structure systems 1102, 1104 that have the measurement bars 100(1), 100(2) side by side. A transmitting microwave sensor part 102(1) of the microwave sensor 102 of one of the measuring structure system 1102 may transmit microwave radiation through the soil 10 to a receiving part 102(2) of the microwave sensor 102 of the other measuring structure system 1104 while the rotation of the measuring structure systems is synchronized.In an embodiment an example of which is illustrated in Fig 11C, the measurement bar 100, which may be a single measurement bar 100, may be pushed toward the ground such that it is driven into the ground and inside the soil 10. The cut 600 that has a vertical depth but not lateral length is formed (lateral dimension of the cut is limited to thickness of the bar). Then, the measurement bar 100 is pulled upward back from inside of the ground. Because the bar 100 has at least one microwave sensor 102, the microwave sensor 102 may make measurements during going down into the ground, staying inside the ground and / or rising from the ground.

[0064] In an embodiment an example of which is illustrated in Fig 11D, the measurement apparatus comprises at least two measurement bars 100(1), 100(2). They may synchronously be pushed toward the ground such that they are driven into the ground and inside the soil 10. Then, the measurement bars 100(1), 100(2) are pulled upward back from inside of the ground. Because the bars 100(1), 100(2) have at microwave sensors 102, the microwave sensors 102 may make measurements during going down into the ground, staying inside the ground and / or rising from the ground. One of the bars 100(1), 100(2) may be replaced by the reflector 1000 (see Fig. 10). The reflector 1000 may travel continuously inside the country like explained in association with Fig. 10, or be pushed down and pulled up like the measurement bar 100.

[0065] In Figs 11C and 11D, the measurement bars 100 may be pushed down and pulled up by a pneumatic, hydraulic and / or electric system 1110. In the pneumatic and hydraulic system there may be a cylinder and a piston. The piston may be connected with the measurement bar 100. When the piston is made to move up and down by pneumatic and / or hydraulic pressure, the measurement bar 100 also move correspondingly. The electric system may comprise an electric motor that moves the measurement bar 100 up and down.

[0066] In an embodiment, the at least one microwave sensor part 102(1) to 102(3) may include a battery (not shown in Figures). The battery may be charged by the electric energy generated by the generator 900 and / or the vibration mechanism that transforms the kinetic energy into the electric energy.In an embodiment, the measurement apparatus may comprise a temperature measuring sensor 950 that may measure temperature of the soil 10 in one or more depths in the range of a depth of the at least one cut 600 and / or in air. The data processing unit 108 may determine the at least one property of the soil 10 at a plurality of locations based on the transmission of the measurement of the soil 10 from the at least one microwave sensor 102. Additionally, the temperature measurement may be utilized in calibration of the microwave measurement and in temperature compensation of the measured values. In an embodiment, the measurement apparatus may measure phase and attenuation of the microwave transmission, and the data processing unit 108 may determine percentage of moisture and / or density of the soil 10 based on said measured parameters.

[0067] In an embodiment, the measurement apparatus may measure a resonance frequency and at least one of attenuation and Q-value of the microwave resonance, and the data processing unit 108 may determine at least one of moisture and density and / or porosity of the soil 10. The density and / or porosity may be measured in addition to the gravimetric percentage of moisture.

[0068] In embodiments, where the measuring blade 100 is a rotating disc the microwave radiation is transferred through a rotating coaxial connector. The operational electric power may also be transferred to the at least one microwave sensor 102 through a rotating connector from the microwave electronics circuit 106. The use of the rotating coaxial connector may be avoided by using a rotating circular waveguide, for example.

[0069] In general, the data transfer between the microwave electronics circuit 106 and the data processing unit 108 may be performed in a wired or wireless manner.

[0070] In an embodiment, the microwave measurement may be performed using frequency modulated continuous wave (FMCW) technique. The data processing unit 108 can calculate the amplitude i.e. attenuation and the phase of the microwave signals using I (in-phase) and Q (quadrature) signals of the quadrature demodulation. Alternatively, the at least one microwave sensor 102may feed the amplitude and phase information to the data processing unit 108, and the data processing unit 108 then forms the at least one property of the soil 10 based on the amplitude / attenuation and / or phase information. The phase information may also be understood to be delay information. A person skilled in the art is familiar with microwave technology, per se.

[0071] Fig. 14 illustrates an example where a drag coulter that includes a microwave sensor creates the furrow. The drag coulter may act as a disc coulter 752. The disc coulter 752 may form a furrow in the soil 10. The disc coulter 752 has at least one microwave sensor 102 that performs repeatedly or continuously a near-field measurement downward i.e. in a vertical direction. Then, the microwave sensor 102 is located at the head of the disc coulter 752, which places it at the bottom of the furrow or cut 600, where its measurement is directed downward for measuring a property of the soil 10 at the bottom of the cut 600 while it is moving inside the cut 600. Additionally, the at least one microwave sensor 102 may measure repeatedly on one or more sides of the measuring blade 100 and the cut 600.

[0072] Fig. 15 illustrates an example of a seeder 760 that has a tube system 750 and a disc coulter 752. The seeder 760 maybe self-propelled or it may be pulled by a tractor. The tube system 750 delivers the agricultural input 754 such as seeds and / or fertilizer(s) into the soil 10 while the disc coulter 752 forms the cut 600 to the soil 10 when the planter 760 is moving. The planter 760 has the measurement apparatus 4 and it may adjust the depth at which the disc coulter 752 is within the soil 10 based on the measurement.

[0073] Fig. 16 illustrates an example of disc coulter 752 in the form of a cutting disc 770. In general, there are various types of coulters and Figs 14 and 16 present examples of them. The disc-type disc coulter is rotating disc that slices through the soil 10 to create a narrow furrow. In this manner, it reduces soil disturbance. In an embodiment, the depth of the cutting disc 770 can be controlled and adjusted. The tube system 750 then delivers the agricultural input into the adjusted depth. Although the cutting disc 770 is rotating the tube system 750 does not rotate withthe disc 770, but its vertical depth inside the soil 10 depends on the depth adjustment of the cutting disc 770.

[0074] Fig. 16 shows that the agricultural input 754 is delivered to the desired depth where the measured property matches the desired value. The same principle applies also to Figs 14 and 15.

[0075] In this manner, the seeds and / or the fertilizer(s) can be delivered into soil 10 where the measured property is at least approximately what is desired.

[0076] This document presents a measurement apparatus for performing subterranean measurements. The measurement apparatus 4 comprises at least one measuring structure 2 comprising at least one microwave sensor 102 for performing the subterranean measurements. The measuring structure 2 digs into the ground and moves inside a cut 600 of the soil 10 while the measurement apparatus 4 moves on the ground. Each of the at least one measuring structure 2 moves in contact with the soil 10 within the cut 600.

[0077] The at least one microwave sensor 102 performs measurements at and / or below the ground level 12 within the cut 600 repeatedly when moving inside the cut 600. The at least one measuring structure 2 comprises at least one of the following:

[0078] a) a rotating measurement disc that rotates around its central axis CA and moves forward with the measurement apparatus 4 (see Fig.9);

[0079] b) a combination of a tube system 750 and a disc coulter 752 that transfer agricultural input 754 through the tube system 750 into the soil 10, the measurement apparatus 4 adjusting a depth of the disc coulter 752 inside the soil 10 based on measurements of the at least one microwave sensor 102, the disc coulter 752 being configured to form the cut 600 (see Figs 14, 15);

[0080] c) a combination of a non-rotating bar 100 and a rotating cutting blade 302 wherein the non-rotating bar follows a rotating cutting blade 302 that forms the cut 600, in the direction of movement of the measurement apparatus 4 (see Fig.

[0081] 6);

[0082] d) a pair of measurement bars 100 extending radially outwards from a shaft 1100, which rotates during operation and movement of the measurementapparatus 4, the measurement bars penetrating the soil 10 repeatedly and move vertically inside the soil 10 (see Figs 11A, 11B); and

[0083] e) a pair of non-rotatable measurement bars 100(1), 100(2) at a nonzero distance from each other pushed into and pulled out of the soil 10 during movement of the measurement apparatus 4 (see Figs 11C and 11D).

[0084] The agricultural input 754 may comprise seeds and / or fertilizers. The fertilizer(s) may be in solid form or in liquid form.

[0085] Fig. 17 illustrates an example of a series coupling of microwave sensors 102(1) to 102(N). The microwave sensors 102(1) to 102(N) maybe coupled with sensor switches 780(1) to 780(N), and a control signal from the microwave electronics circuit 106 controls them such that only one microwave sensor 102(1) to 102 (N) is active at a time. In Fig. 17, the sensor switch 780(1) passes the connection to the sensor switch 780(2) which is controlled to connect the microwave sensor 102(2) with the microwave electronics circuit 106 for a measurement. The microwave sensors after the microwave switch 102(2) are disconnected from the microwave electronics circuit 106. In this manner, the use of cables between the microwave electronics circuit 106 and sensors 102(1) to 102 (N) is minimized because only one cable pair is used to measure the microwave sensors and to transfer the measurement information from the microwave sensors.

[0086] Fig. 17 also shows a temperature sensor 785.

[0087] In Fig. 17, the microwave sensors are illustrated to be coupled to a bar that is dragged inside the ground. In such a case, the higher the reference number of the microwave sensor the deeper it is. However, the series coupling of the microwave sensors can be applied also in the case they are attached with a disc.

[0088] Fig. 19 illustrates an example of an attenuation measurement. The result of a transmission attenuation measurement depends on how well antennas 964, 968 of the microwave sensors 102 are matched with respect to soil 10. In an embodiment, the attenuation measurement may be made more accurate by measuring the matching of antenna and signals from antenna to antenna in both directions and making correction to the measurement result.A first measurement may be made such a first switch A, which is connected with a microwave transmitter 960, is in position 1. In this way, the microwave radiation propagates to a circulator 962. The circulator 962 forwards the microwave radiation to a first antenna 964. The reflection from the soil is received by the first antenna 964 and the circulator 962 delivers the reflection to a second switch B which is turned in a position 1. That allows a receiver 966 to receive the reflection for a reference.

[0089] A second measurement may be such that the first switch A is in position 1 and the second switch B is in position 2. Now, the microwave radiation travels from the first antenna 964 through soil 10 to a second antenna 968. A second circulator 970 that receives the microwave radiation from the second antenna couples the microwave radiation to the second switch B that is in position 2 and the second switch B couples the microwave radiation with the receiver 966. In this manner, strength of the reflection and strength of the microwave radiation passed through the soil may be measured and the actual attenuation of the microwave radiation while passing through the soil may be determined. Namely, the strength of the reflection can be subtracted from the transmission power of the microwave radiation.

[0090] A third measurement may be such that the first switch A is in position 2 and the second switch B is in position 2. In this measurement, the microwave radiation transmitted by the transmitter 960 is coupled from the switch A to the second circulator 970 which couples the microwave radiation to the second antenna 968. Then the microwave radiation reflects from the soil 10 back to the second antenna 968 and the second circulator 970 couples the reflected microwave radiation to the switch B. From the switch B the reflected microwave radiation is connected with the receiver 968.

[0091] In the fourth measurement, the switch A may be in position 2 and the switch B is in position 1. The microwave radiation transmitted by the transmitter 960 propagates through the switch A to the second circulator 970 which couples the microwave radiation to the second antenna 968. The microwave radiation travels through the soil 10 to the first antenna 964 from which the microwaveradiation propagates to the first circulator 962. From there the microwave radiation coupled with the switch B which couples the microwave radiation to the receiver 966.

[0092] The third and fourth measurements enable the measurement of the reflection and the transmission through the soil 10. When the strength of the reflection is subtracted from the transmission power, an actual attenuation of the microwave radiation caused by the soil 10 can be determined. In an embodiment an example of which is illustrated in Fig. 19, the measurement apparatus 4 may comprise a data processing unit 108 that comprises one or more processors 1300 and one or more memories 1302 including computer program code. The one or more memories 1302 and the computer program code may, with the one or more processors 1300, cause the measurement apparatus 4 at least to receive wired and / or wireless transmission from the at least on microwave sensor 102, and determine the at least one property of the soil 10 based on information carried by the transmission.

[0093] The term “computer” includes a computational device that performs logical and arithmetic operations. For example, a “computer” may comprise an electronic computational device, such as an integrated circuit, a microprocessor, a mobile computing device, a laptop computer, a tablet computer, a personal computer, or a mainframe computer. A “computer” may comprise a central processing unit, an ALU (arithmetic logic unit), a memory unit, and a control unit that controls actions of other components of the computer so that steps of a computer program are executed in a desired sequence. A “computer” may also include at least one peripheral unit that may include an auxiliary memory (such as a disk drive or flash memory), and / or may include data processing circuitry.

[0094] A user interface 110, which shown in Figs 1, 2, 7, 8, 10 and 19, means an input / output device and / or unit. Non-limiting examples of a user interface include a touch screen, other electronic display screen, keyboard, mouse, microphone, handheld electronic controller, digital stylus, display screen, speaker, and / or projector for projecting a visual display. The user interface 110 may be a part of the data processing unit 108 or a separate device (as drawn in Fig. 19).In an embodiment, the one or more memories 1302 and the computer program code perform, with the one or more processors 1300, determination of at least moisture of the soil 10 based on the measurement of the soil 10 by the at least one microwave sensor 102. The one or more memories 1302 and the computer program code control, with the one or more processors 1300, a depth of the seed and / or fertilizer disc coulter 752 for controlling seeding depth and / or fertilizer placement depth inside the cut 600 within the soil 10 based on the determination of moisture. In an embodiment, the one or more memories 1302 and the computer program code guide the seed and / or fertilizer disc coulter 752 to follow a constant moisture level within the soil 10. In that manner, seeds and / or fertilizer(s) a placed into an environment within the soil 10 where the moisture level / percentage is constant. The moisture level may be set to a desired value. The desired moisture level may depend on the seeds. Seeds of a given plant species usually require an optimum moisture level for successful germination.

[0095] The measurement apparatus 4 may measure the moisture level and control the depth by adjusting mechanically the depth of the disc coulter 752 inside the soil 10 such that the moisture level remains constant at least approximately. If the measured moisture level is lower than target level, the measurement apparatus 4 may push the disc coulter 752 deeper into the soil 10. If the measured moisture level is bigger than target level, the measurement apparatus 4 may pull the disc coulter 752 upwards inside the soil 10. The data processing unit 108 may comprise or may be connected to a communication unit 112. The communication unit 112 may transmit the measured data to a separate data processing device or a data storage. The separate data processing device or the data storage may refer to a cloud server. In this document, the data processing unit 108 represents both the data processing unit that is local and can be carried by the support structure 104 and any remote data processing unit 108 at the area that is measured or anywhere on the earth. The data processing itself is not dependent where the data processing is performed.

[0096] In an embodiment examples of which are shown in Fig. 1, 7, 8, 10 and 13, the measurement apparatus 4 may comprise a positioning apparatus 120. Theposition measurement of the at least one microwave sensor 102 at each moment is performed by the positioning apparatus 120, and it may be based on signals from a radio system, an irrigation system and / or from a satellite positioning system, for example. The satellite positioning system may be the Global Positioning System (GPS), GLONASS (Global Navigation Satellite System), Galileo, BeiDou and NavIC (Navigation with Indian Constellation), for example. The signals from known positions from one or more base stations, water distributors and / or from satellites can be used to define the position of the at least one microwave sensor 102 at each moment. The data processing unit 108 may form a map of the at least one property of the soil 10 over an area that is measured based on data of locations of the at least on microwave sensor 102 during the measurement of the soil 10. The data processing unit 108 may form a map of distribution of the at least one property of the soil 10 over an area. The map may be two-dimensional including two lateral dimensions and a vertical value at fixed depth or three-dimensional including two lateral dimensions and a vertical dimension. Like in all examples, the at least one microwave sensor 102 can measure a property of the soil 10 in a vertical dimension.

[0097] In this document, it may be at least one quality and / or at least one quantity that can be measured. In an embodiment, the quality may be the moisture percentage, porosity or the like of the soil 10.

[0098] In an embodiment, the data processing unit 108 may form a two-dimensional map of a line that is measured. The measurement line may be beside a row of a potato bed, or the line is beside the row of any plants in general (the plant beds can be seen in Figs 20A and 20B). In one dimension such as the x-axis, there is a location and in the other dimension such as the y-axis, there is the at least one property. The data processing unit 108 may form a three-dimensional map from the measurement of many lines. The data processing unit 108 may form a four-dimensional map from the measurement of many lines and with information on the at least one property in the depth direction of the soil 10.

[0099] In an embodiment an example of which is illustrated in Figs 20A and 20B, the data processing unit 108 may control an irrigation system based on the atleast one property of the soil 10. The water source 1400 may be a water storage tank or a cistern. Sometimes the water source 1400 may be a well, a lake or a river. A pump 1402 pumps water from the water source 1400 to water distributors 1404. The water distributors 1404 of the irrigation system may include rotors, impact sprays, spray heads, drip lines, bubblers or the like. The rotors have a nozzle, and when the rotor rotates the nozzle distributes water evenly over a large radius. The impact sprays are like sprinklers. They can be recognized by a clicking sound when they turn. The spray heads spray water over a fixed area. The drip lines deliver water through pipes that have small holes for emitting water to the roots of plants. The pipes may be embedded inside the soil 10. The bubblers emit a larger stream of water than a drop at the base of the plant which may often be large such as trees. The water distributors in Fig.20A are immobile with respect to the plant beds BED 1 to BED N.

[0100] Fig. 20B illustrates an example where the water distributors can move over the plant beds BED 1 to BED N. In Fig.20B, the water distributors are hanging over the plants of the plant beds BED 1 to BED N. Deviation from the illustrations in Figs 20A and 20B, there may be irrigation systems where the water distributors 1404 rotate over a large radius. However, there operation principle is similar to those in Figs 20A and 20B. In any case, a person skilled in the art is familiar with various irrigation systems, per se.

[0101] The data processing unit 108 may control the dosage of water as function of a unit of area and time based on the measurement of the at least one microwave sensor 102 by controlling the nozzles of the water distributors 1404 and / or the pump 1402. In an embodiment, the data processing unit 108 may calibrate the dosage of water based on the measurement of temperature, for example.

[0102] Note, the water delivered to plants in the plant beds may include a controlled percentage of one or more fertilizer and / or one or more insecticide. The data processing unit 108 may control them by controlling their feed to water delivered to the plants. Their dosage may be controlled as a dosage per unit of area per time unit.The data processing unit 108 may control water flow output by each water distributor 1404 independently depending on the at least one property of the soil 10. The data processing unit 108 may control the speed of the movement of the water distributors 1404 over the plant beds BED1 to BED2.

[0103] The map of any of the dimensions could serve as the basis of the control, for example. Although moisture percentage may seem to be a key issue for the control of the irrigation, the density and / or porosity of the soil 10 may also be used to control the irrigation because different soil structures require different irrigation. Still additionally, temperature, weather forecast, sunshine and its length, wind, cloudiness, number and types of insects, dust, pollution and / or the like, for example, without forgetting the plant types’ requirements may be utilized in control of the irrigation. The property may be a percentage of moisture, density and / or porosity of the soil 10. Where the land has a suitable moisture percentage or higher than suitable moisture percentage, the data processing unit 108 may stop irrigation. Where the land has a lower moisture percentage than desired, the data processing unit 108 may start or continue irrigation. The data processing unit 108 may control the irrigation depending on resolution of the microwave measurement. The resolution of the measurement may be about 1 m2depending on the size of the plant bed. Additionally, the radius of the at least one measuring blade 100 of a circular form may affect the resolution of the measurement.

[0104] In orchards and vegetable gardens, tilling and tidying up row spacing is carried out using rakes, cultivators or mowers mounted on tractors. The microwave measuring devices installed in these devices may provide a comprehensive picture of the water demand of the entire growth parcel and an individual point, and thus it is possible to control the current irrigation need or design the optimal irrigation system for the parcel.

[0105] The microwave measuring device mounted on a mobile irrigation machine provides accurate information about the soil moisture at the irrigation point. Based on this information, the running speed of the mobile precipitator can be adjusted, and on the basis of the same information, the amount of water enteringthrough the nozzles can be changed. Comprehensive information on soil moisture provided by a mobile microwave measuring device reduces water and energy use.

[0106] In an embodiment, the planting depth of the seeds may be controlled based the measurement of the soil 10. When there is variation of the at least one property of the soil 10, such as moisture, in different locations of the measured area, the planting depth(s) of the seeds of plants may correspondingly vary. For example, the seeds may be planted the deeper the drier the soil 10 is. Additionally, the planting depth may also depend on the type of the soil 10, the types being loamy soil, clay soil and rocky soil, for example. In a corresponding manner, the fertilizer(s) may be applied at desired depths depending the properties of the soil 10 at various locations and / or during different weather or season.

[0107] In areas where there is not much rain during the growing season, cereals, maize, soybean, oilseeds, hay, etc. Sown using residual water from the ground during the winter or rainy season. The seed of the plant to be sown must be caught in moist soil, but due to its small size, it should not go too deep. A seed sown at the right depth and temperature in the right soil will quickly emerge and grow roots that gravitate towards moisture. The microwave measuring device presented in this document provides accurate information about the optimum soil moisture, temperature and depth for the seed. Based on this information, the depth of the individual seed drill coulter or the entire machine is adjusted so that the seed sticks to the moist soil, but not too deep.

[0108] The yield forecast of cultivated plants can be made by taking samples from the crop or by measuring various parameters of the crop, such as the leafy green index and coverage. In addition to this, it may be useful to know the plant species and variety to be cultivated, the date of sowing, the type of soil, the heat sum, weather conditions. Based on this information, it is possible to predict the future harvest with the help of the growth models in use, if the weather forecast for the remaining growing season is known. The yield forecast can be improved by information based on the microwave measurements of the soil 10 at various locations. When also information of the performed irrigation and the plannedirrigation or soil moisture is known, the yield forecast can be made in an optimized manner.

[0109] The field is tilled with tractor-mounted implements such as ploughs, harrows, cultivators. The microwave measuring device presented in this document and installed on these machines, can be used to comprehensively measure soil moisture in connection with normal field work, resulting in a moisture map of the field. This can be used to make and implement cultivation and drainage plans as well as all plans related to fields and plant growth.

[0110] The blades of the tuber and root vegetable lifting machine must go below the plant part inside the soil to prevent the plant parts from breaking. On the other hand, the lifting web must not go too deep in order to achieve good lifting power and minimise energy consumption. The depth of the lifting web is mechanically adjusted using weight rollers and hydraulics. The information provided by microwave measuring devices, knives or discs, installed on the lifting head of the harvesting machine, makes it possible to determine the depth of the tubers or root vegetables of the plant to be harvested inside the soil 10. The depth of the lifting machines can be adjusted optimal based on the information received from the microwave measurements. Then, the effectiveness of the lifting machine may be improved, energy is saved and the harvest will not be damaged.

[0111] Fig.21 is a flow chart of the subterranean measurement method and its utilization for control of an irrigation system. In step 1600, the soil 10 is measured repeatedly at and / or below the ground level by the at least one microwave sensor 102 of the at least one measuring structure 2 of a measurement apparatus 4, while the measurement apparatus 4 is moving along the ground, the measuring structure 2 has dug into the ground and the at least one microwave sensor 102 is moving inside a cut 600 of the soil 10 in contact with the soil 10 and measuring the soil 10 within the cut 600 for determining at least one property of the soil 10.

[0112] In step 1602, which is optional, the at least one property of the soil 10 is determined by a data processing unit 108 at a plurality of locations by a data processing unit 108 based on the measurements and the movement of themeasurement apparatus 4 along the ground. In step 1604, which is optional, the irrigation system is controlled based on the at least one property of the soil 10.

[0113] The method shown in Figure 21 may be implemented as a logic circuit solution or computer program. The computer program may be placed on a computer program distribution means for the distribution thereof. The computer program distribution means is readable by a data processing device, and it encodes the computer program commands, carries out the measurements and optionally controls the processes on the basis of the measurements.

[0114] The measurements taught in this document have a high representativeness over the area which is measured. For example, the point measurements of the prior art are too sparse for the representativeness. The remote measurements of the prior art fails to give information deeper in the soil. The solution presented in this document has the advantages of the various prior art measurements.

[0115] The computer program may be distributed using a distribution medium which may be any medium readable by the controller. The medium may be a program storage medium, a memory, a software distribution package, or a compressed software package. In some cases, the distribution may be performed using at least one of the following: a near field communication signal, a short distance signal, and a telecommunications signal.

[0116] It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the example embodiments described above but may vary within the scope of the claims.

Claims

What is claimed is:

1. A measurement apparatus for performing subterranean measurements, c h a r a c t e r i z e d in that the measurement apparatus (4) comprises at least one measuring structure (2) comprising at least one microwave sensor (102) for performing the subterranean measurements;the measuring structure (2) is configured to dig into the ground and move inside a cut (600) of the soil (10) while said measurement apparatus (4) is configured to move on the ground, and each of the at least one measuring structure (2) is configured to move in contact with the soil (10) within the cut (600); and the at least one microwave sensor (102) is configured to measure at and / or below the ground level (12) within the cut (600) repeatedly when moving inside the cut (600), wherein the at least one measuring structure (2) comprises at least one of the following:(a) a rotating measurement disc configured to rotate around its central axis (CA) and move forward with the measurement apparatus (4);(b) a combination of a tube system (750) and a disc coulter (752) configured to transfer agricultural input (754) through the tube system (750) into the soil (10), the measurement apparatus (4) being configured to adjust a depth of the disc coulter (752) inside the soil (10) based on measurements of the at least one microwave sensor (102), the disc coulter (752) being configured to form the cut (600);(c) a combination of a non-rotating bar (100) and a rotating cutting blade (302) wherein the non-rotating bar (100) is configured to follow a rotating cutting blade (302), which is configured to form the cut (600), in the direction of movement of the measurement apparatus (4);(d) a pair of measurement bars extending radially outwards from a shaft (1100), which is configured to rotate during operation and movement of the measurement apparatus (4), the measurement bars being configured to penetrate the soil (10) repeatedly and move vertically inside the soil (10); and(e) a pair of non-rotatable measurement bars at a non-zero distance from each other, configured to be pushed into and pulled out of the soil (10) during movement of the measurement apparatus (4).

2. The measurement apparatus of claim 1, c h a r a c t e r i z e d in that a data processing unit (108) is configured to determine at least one property of the soil (10) at a plurality of locations based on the measurements of the at least one microwave sensor (102).

3. The measurement apparatus of claim 1, c h a r a c t e r i z e d in that the at least one measuring blade (100) of the measuring structure (2) is configured to form the cut (600) in the soil (10), and / or the measurement apparatus comprises at least one cutting blade (302), and each of the cutting blade (302) is configured to form the cut (600) for one of the at least one measuring blade (100), and each of the at least one cutting blade (302) and / or the at least one of the measuring blade (100) is configured to cut the soil (10).

4. The measurement apparatus of claim 1, c h a r a c t e r i z e d in that at least one of the at least one measuring blade (100) of the measuring structure (2) has a shape of a disk and said at least one of the at least one measuring blade (100) is configured to rotate around its central axis (CA) in order to form the cut (600) in the soil (10) and / or travel inside the cut (600) of the soil (10) for making surfaces of the cut (600) to be in contact with each other when no blade is between them.

5. The measurement apparatus of claim 1, c h a r a c t e r i z e d in that at least one of the at least one measuring blade (100) of the measuring structure (2) is non-rotatable, and said at least one of the at least one measuring blade (100) is configured to be forced through the soil (10) for travelling in the cut (600) formed by cutting blade (302).

6. The measurement apparatus of claim 1, c h a r a c t e r i z e d in that the measurement apparatus comprises at least one pair of the measuring blades(100(1), 100(2) ) of the measuring structure (2) at a non-zero distance (D) from each other, and the microwave sensor parts (102(1), 102(2)) of different measuring blades (100(1), 100(2)) of said at least one pair are configured to transmit a microwave signal through the soil (10) between the measuring blades (100(1), 100(2)) of said at least one pair for measuring the at least one property of the soil (10) within distance (D).

7. The measurement apparatus of claim 1, c h a r a ct e r i z e d in that the measurement apparatus comprises at least one pair of the measuring blades (100(1), 100(2)) of the measuring structure (2) at a non-zero distance from each other, one blade (100(1)) of said one pair of the measuring blades (100(1), 100(2)) comprises at least one microwave sensor (102), and the other of said pair of the measuring blades (100(1), 100(2)) comprises a reflector (1000); and the at least one microwave sensor (102) is configured to transmit microwave communication through the soil (10) toward the reflector (1000) that is configured to reflect the microwave communication back to the at least one microwave sensor (102).

8. The measurement apparatus of claim 1, c h a r a ct e r i z e d in that measurement apparatus comprises a data processing unit (108) that comprises one or more processors (1300); andone or more memories (1302) including computer program code; and the one or more memories (1302) and the computer program code configured to, with the one or more processors (1300), cause measurement apparatus at least to receive transmission of a measurement from the at least one moving microwave sensor (102), and determine at least one property of the soil (10) based on the measurement of the soil (10).

9. The measurement apparatus of claim 8, c h a r a ct e r i z e d in that the measurement apparatus comprises a temperature measuring sensor (950) that is configured to measure temperature of the soil (10) in one or more depths in the range of a depth of the at least one cut (600) and / or in air, and the data processingunit (108) is configured to determine the at least one property of the soil based on both the data on the measurement of the soil (10).

10. The measurement apparatus of claim 9, c h a r a c t e r i z e d in that the at least one microwave sensor (102) is configured to measure phase and attenuation of the microwave transmission, and the data processing unit (108) is configured to determine percentage of moisture and / or density of the soil based on measurements of said phase and attenuation.

11. The measurement apparatus of claim 9, c h a r a c t e r i z e d in that the at least one microwave sensor (102) is configured to measure a resonance frequency and at least one of attenuation and Q-value of the microwave transmission, and the data processing unit (108) is configured to determine at least one of moisture and density of the soil (10) based on measurements of the resonance frequency and the one of attenuation and the Q-value.

12. The measurement apparatus of claim 9, c h a r a c t e r i z e d in that the data processing unit (108) is configured to control an irrigation system based on the at least one property of the soil (10).

13. The measurement apparatus of claim 9, c h a r a c t e r i z e d in that the measurement apparatus comprises a positioning system (120), and the data processing unit (108) is configured to form a map of distribution of the at least one property of the soil (10) over an area that is measured based on data of locations of the at least on microwave sensor (102) from the positioning system (120) during measurement.

14. The measurement apparatus of claim 8, c h a r a c t e r i z e d in that the one or more memories (1302) and the computer program code are configured to, with the one or more processors (1300), perform determination of at least moisture of the soil (10) based on the measurement of the soil (10) by the at least one microwave sensor (102); and control a depth of the seed and / or fertilizer disc coulter (752) for controlling seeding depth and / or fertilizerplacement depth inside the cut (600) within the soil (10) based on the determination of moisture.

15. A measurement method of performing subterranean measurements, c h a r a c t e r i z e d bymeasuring (1600) repeatedly the soil (10) at and / or below the ground level by the at least one microwave sensor (102) of the at least one measuring structure (2) of a measurement apparatus (4), while the measurement apparatus (4) is moving along the ground, the measuring structure (2) has dug into the ground and the at least one microwave sensor (102) is moving inside a cut (600) of the soil (10) in contact with the soil (10) and measuring the soil (10) within the cut (600) for determining at least one property of the soil (10), wherein each of the at least one measuring structure (2) comprising a measuring disc, a measuring bar or a pair of measuring bars performs at one of the following during operation and movement of the measurement apparatus (4):(a) the measuring disc rotates around its central axis (CA) while moving forward with the measurement apparatus (4);(b) a combination of a tube system (750) and a disc coulter (752) transfer agricultural input (754) through the tube system (750) into the soil (10), the measurement apparatus (4) adjusting a depth of the disc coulter (752) inside the soil (10) based on measurements of the at least one microwave sensor (102), wherein the disc coulter (752) forming the cut (600);(c) a combination of a non-rotating bar (100) and a rotating cutting blade (302) such that the non-rotating bar (100) follows a cutting disc (502) in the direction of movement of the measurement apparatus (4);(d) the pair of measurement bars extending radially outwards from a shaft (1100), which rotates during movement of the measurement apparatus (4), the measurement bars penetrating the soil (10) repeatedly and moving vertically inside the soil (10); and(e) the pair of non-rotatable measurement bars spaced apart by a nonzero distance from each other, pushes into and pulls out of the soil (10) during movement of the measurement apparatus (4).

Images