DE102008009753B3 - Method for contactless determination of biomass and morphological parameter of plant populations, involves treating plants of populations with ultrasound by releasing acoustic pulses from ultrasound source - Google Patents

Abstract

The method involves treating plants of the populations with ultrasound by releasing acoustic pulses from an ultrasound source with a sound frequency of 30 to 300 kilohertz and pulse duration of maximum 500 microseconds in a cyclic manner. The air temperature is measured in a concurrent manner in order to determine the temperature-dependent sound speed. A timer is started with a certain period of time simultaneously with the releasing of the acoustic pulses.

Description

The The invention relates to a method for the contactless determination of the biomass and morphological parameters of plant stands, in which plants the stock with an attached from a mobile carrier ultrasonic source emitted sound field during the crossing which reflected from the plants and the soil Schallechos by one on the carrier fixed receiver recorded and from this, after conversion into digital signals to a Evaluation and signal processing unit to be passed, the the signals currently being evaluated, stored on a data carrier and stored on one Monitor displays, optionally in an electronically controlled Application unit, the signals to control commands for discharging Production resources are processed, applying production resources be processed, the sound field is substantially perpendicular to and the ultrasonic source at a significant distance above the Invented is, the plants in an optimally effective range of the sound field immerse, and the ultrasonic source cyclically sound pulses on the stock emits, with the sound pulses in at different Depths of the existing foliage and possibly one after the other from the ground in spatial attributable n-echo echoes are reflected, and these echoes behind Decode to a measure of the current Biomass, their vertical distribution in the stock and the morphological Parameters of the stock

The known reflection-optical methods allow a relatively large measuring field, For example, scanning widths up to several meters per sensor and can when using a separate light source, regardless of Daylight can be used.

One fundamental Disadvantage of these known methods, however, is that not the biomass directly, but the amount of chlorophyll pigments per unit area is determined. Changes The chlorophyll concentration in the stock, so this leads despite the same Biomass to a change of the measured value.

One Another disadvantage is that suitable sensors are relatively expensive, since they are in small quantities especially for the purpose of use. Also, go with this known Method corresponding height information lost from inventory.

In the DE 10 2005 050 302 A1 is a method for contactless determination of the current nutritional status of a crop stand and for processing this information, taking into account other parameters such as crop and / or variety and / or development stage and / or yield target in a fertilizer recommendation described in which of a part of the plant population at least one digital image recorded by means of an image recording system in at least two spectral channels, from the image of the current nutritional status determined by an image analysis and from the latter, the fertilizer recommendation is derived.

This known prior art has the disadvantage that the method dependent on the ambient light is and the big ones to be processed data require a correspondingly complex hardware and software. Furthermore If only a two-dimensional projection of the stock is available, so that altitude information just as lost.

From the DE 103 29 472 A1 Furthermore, a device for measuring the crop density, in particular the green masses of the plant population of an agricultural crop density for controlling and / or regulating an agricultural distribution machine is known, wherein the device has at least one signal to an on-board computer-supplying sensor with a transmitter and a receiver. The sensor is designed as a triangulation sensor. By means of the sensor, the inventory level of the plant population and from the signals by means of a stored in the on-board computer in a storage medium evaluation program, the crop density is determined.

This known method works with a laser, which is on the measuring object is focused. The disadvantage here is the very small point or linear Measurement field. A random, For example, caused by drilling errors streaking of the stock in the direction of travel can already here to unrepresentative measurement results to lead.

The DE 40 42 672 C2 discloses an on-board computer system for agricultural machine and / or equipment combinations, consisting of a farm tractor and coupled to this and designed as fertilizer spreader and / or sprayer agricultural distribution machines, via the on-board computer system of the tractor and / or the coupled distribution over stored in the on-board computer system and / or entered setting values can be adjusted, controlled and / or regulated, wherein the on-board computer system has at least one sensor element cooperating with the on-board computer, which provides information about the area to be spread. The sensor element is designed as a non-contact sensor and currently records information about the nature and condition of the plant growth by contactless scanning of the the plants to be spread. This information is transmitted to the on-board computer, which currently determines the nutrient requirement and / or the nutrient supply of the plants by means of a stored evaluation program, wherein due to the nutrient requirement thus determined, the direct control of the metering is done by the on-board computer. The sensors used may be ultrasonic sensors or infrared sensors.

This Although known prior art describes a vehicle-based measuring system, however the attached to the tractor is at a small distance above the Invented, so such a system becomes defective due to the small scanning area Results.

From the GB 2 025 665 A For example, a agricultural or forestry spraying apparatus is known in which spraying is accomplished with a series of spray nozzles.

The Are spray nozzles mounted on a spray arm, which extends substantially parallel to the soil surface. This state of the art is based on the knowledge that comes from the ground and the plants reflected radiation for position adjustment of spray arm parallel to the soil surface to use. A direct determination of biomass and morphological Parameters of the plants from the stock does not take place.

at In this prior art, the object of the invention is to provide the method of determining the biomass and morphology of plant stocks such to improve that measurement accuracy through a direct determination biomass and morphological parameters of plants the stock while at the same time reducing costs elevated becomes.

These Task is by a method of the type mentioned solved with the features of claim 1.

advantageous Embodiments of the method are the dependent claims.

The inventive solution makes it possible biomass and, for the first time, morphological parameters such as the number of sheets, the position of leaves, the uniformity Growth and vertical distribution of biomass of plants to determine directly and up-to-date from the plants, without affecting the quantity the chlorophyll pigments per area To fall back on to have to. This is further associated with the advantage that greater measurement certainty is achieved and the farmer over a process-reliable and cost-effective Method of efficient, directly oriented to the actual needs of the plants Application of certain means of production, such as growth regulators, features.

The to carry out the method according to the invention The device used has a compact and robust construction Simultaneous ease of use. Of particular advantage is that as ultrasonic sensors cost-effective commercial Ultrasonic transducers can be used without consuming and expensive special sensors are necessary.

These Device leaves in a simple way, for example, in various ways a short boom next to the tractor, directly on the tractor roof or also on a linkage a field sprayer o. The like., Mount with little effort.

The inventive method is characterized in that the generated by the ultrasonic source Sound field substantially perpendicular to and the ultrasound source at a considerable distance above the Invented being, the plants being outside the blind zone of the cone of sound from the optimally effective measuring range of the cone of sound. From the ultrasound source will be Cyclic sound pulses emitted to the stock, which in different Depths of the existing foliage and possibly from the ground one after the other reflected and thus in several, time-separated echoes disbanded become. These echoes become a measure of the current one after decoding Biomass, their vertical distribution in the stock and the morphological Processed parameters of the stock.

• a) zyklisches Beschallen der Pflanzen des Bestandes durch Auslösen von Schallimpulsen aus mindestens einer Ultraschallquelle mit einer Schallfrequenz von 30 bis 300 kHz und einer Impulsdauer von jeweils maximal 500 μs, wobei der zeitliche Abstand der Schallimpulse voneinander mindestens der doppelten Laufzeit des Schalls zwischen Schallquelle und Boden entspricht,
• b) gleichzeitiges Messen der Lufttemperatur zwecks Bestimmung der temperaturabhängigen Schallgeschwindigkeit,
• c) Starten eines Zeitgebers mit einem definierten Zeitschritt simultan mit dem Auslösen des Schallimpulses gemäß Schritt a), wobei in einer Schleife zu jedem Zeitschritt das aktuell reflektierte Echo am Empfänger als Messwert erfasst wird,
• d) Stoppen des Zeitgebers durch Beenden der Schleife gemäß Schritt c), Zusammenfassen aller erfassten Messwerte pro Zeitschritt in einem Echogramm und Übergabe an eine Schnittstelle für die Auswerte- und Signalverarbeitungseinheit,
• e) kontinuierliches Wiederholen der Arbeitsschritte c) und d) zum Zuführen der Echogramme über die Schnittstelle an die Auswerte- und Signalverarbeitungseinheit,
• f) Auslesen und Kalibrieren der Echogramme mit Berücksichtigung der Temperatur gemäß Schritt b),
• g) Bestimmen der Biomasse und/oder der morphologischen Parameter des Pflanzenbestandes in Abhängigkeit der Fruchtart, Sorte und Entwicklungsstadium der Pflanzen aus den Ergebnissen gemäß Schritt f) und optional
• h) Ermitteln der Ausbringmenge an Produktionsmitteln unter Berücksichtigung von Fremddaten wie Applikationsempfehlungen, Fruchtart und Sorte, Entwicklungsstadien, Dosier- und Mitteldaten, meteorologische Daten, besondere Verhältnisse an Senken, Kuppen oder Waldrändern des Schlages.

The process according to the invention is carried out in the following work steps:

• a) cyclic irradiation of the plants of the stock by triggering sound pulses from at least one ultrasonic source with a sound frequency of 30 to 300 kHz and a pulse duration of a maximum of 500 microseconds, the time interval of the sound pulses from each other at least twice the duration of sound between sound source and ground corresponds,
• b) simultaneous measurement of the air temperature for the purpose of determining the temperature-dependent sound velocity,
• c) starting a timer with a defined time step simultaneously with the triggering of the sound pulse according to step a), wherein in a loop at each time step, the currently reflected echo is detected as a measured value at the receiver,
• d) stopping the timer by terminating the loop according to step c), combining all acquired measured values per time step in an echogram and transfer to an interface for the evaluation and signal processing unit,
• e) continuously repeating steps c) and d) for supplying the echograms via the interface to the evaluation and signal processing unit,
• f) reading out and calibrating the echograms with consideration of the temperature according to step b),
• g) Determining the biomass and / or the morphological parameters of the plant population depending on the type of crop, variety and stage of development of the plants from the results according to step f) and optionally
• h) Determining the application rate of production resources taking into account external data such as application recommendations, type of crop and variety, stages of development, dosage and mean data, meteorological data, special conditions at depressions, crests or forest edges of the impact.

Out the measured time differences between emission of the sound pulses and receiving the echo will be absolute distances through the calibration using the sound velocity determined from the current air temperature determined.

Around To reliably rule out measurement errors will be erroneous echoes, especially those echoes that are outside of the distance ultrasonic source ground are present or the off too short distance or come from the blind zone, before the removed further processing.

Of the plant stock to be measured will be at an angle of less as 10 ° to Nadir, d. H. from a substantially vertical position to the plant population, Sonicated at a distance of 2 to 4 m from the floor. A big measuring distance has the advantage of being as possible size Number of plants can be detected by the cone of sound, indicating the accuracy the measurement increases.

The opening angle of the cone of sound is at these geometric relationships the arrangement between 3 and 30 °. The plants to be measured are arranged in the optimal measuring range of the cone of sound. With too large opening angles leads the runtime difference between the signals in the middle and the signals on the edge to a smearing the reflected echoes while too small opening angle too small measuring surfaces have as a consequence.

From A particular advantage is that the sound waves deep into the plant penetrate, making it possible is morphological parameters such as the number of sheets, the Leaf position, uniformity of the growth and the vertical distribution of the biomass in the stock to investigate.

The Special feature of the solution according to the invention in that not only the distance to the nearest object, d. H. the first echo from the first leaf level of the struck plant, but also reflection signals of others, behind the first sheet floor of lying leafy floors and of the soil. The stock density just not be so high that the first sheet already has all completely covers further underlying sheet floors.

Further Advantages and details will become apparent from the following description with reference to the attached Drawings.

The Method using the method used to carry out the method Device will be explained in more detail below with reference to two embodiments.

It shows

1 a schematic representation of an agricultural vehicle with attached to the roof sensor assembly,

2a and 2 B an enlarged view of the measuring system according to the invention from ultrasound source and receiver with sound cone,

3 an example of the signal curve applied to the receiver of the measuring system,

4 a block diagram of the solution according to the invention,

5a and 5b a flow chart of the sequence of the method according to the invention,

6 an example of an echogram,

7 an example of a calibration function for the determination of biomass and

8a to 8d Examples of histograms for determining morphological parameters such as leaf position, number of leaf layers and vertical distribution of biomass to wheat.

example 1

The 1 shows a towing vehicle 1 as a carrier, on its roof 2 a the width of the carrier 1 only slightly overhanging boom 3 is attached. At the ends 4 of the jib 3 is ever an ultrasonic sensor 5 fastened, its sound cone 6 essentially perpendicular to the plant population 7 is aligned. The maximum deviation from the vertical orientation may be up to 10 ° to the nadir. The distance A of the ultrasound sensors 5 from the ground 8th is preferably 2.5 m, but may vary between 2 and 4 m.

As a carrier for the ultrasonic sensors 5 are also agricultural distribution machines, such as sprayers, suitable. In such a case, the ultrasonic sensors can 5 be mounted directly on the boom of the syringe. It is expedient to use two or more ultrasonic sensors 5 attach to the boom of the syringe side by side, making sure that the sound cone 6 the juxtaposed ultrasonic sensors 5 have a sufficiently large distance from each other to exclude mutual interference.

As ultrasonic sensors 5 Commercially available industrial ultrasonic transducers are used in the frequency range between 30 to 300 kHz, which can both emit sound signals and receive sound echoes.

The 2a and 2 B show the measuring principle and the course of the sound cone (club) 6 with depiction of the blind zone and optimal measuring zone in the sound cone in relation to the plant population 7 ,

The ultrasonic sensor 5 essentially consists of an ultrasound source 9 , a receiver 10 and a temperature sensor 11 together. From the ultrasound source 9 cyclically a sound pulse with a sound frequency of, for example 130 kHz and a pulse duration <500 microseconds emitted. The sound impulse spreads at the speed of sound (about 345 m / s, depending on the air temperature), reaches the plant population 7 and penetrate into these. At the leaves arranged at different heights of the plant, the sound pulse is partially reflected as an echo. In the case of stocks that are not too dense, such as wheat, rye or the like, a remaining portion of the sound impulse penetrates to the ground 8th before and is also reflected on this as an echo. The reflected echoes now hit the ultrasound sensor, depending on the depth of the population in which they were reflected one after the other 5 and are registered there.

d

der Abstand Boden zum Sensor und

c

die Schallgeschwindigkeit,

wird der nächste Schallimpuls und Messzyklus ausgelöst. Durch den im Ultraschallsensor 5 integrierten Temperaturmessfühler 11 wird zeitgleich mit dem Aussenden des Schallimpuls die Lufttemperatur T ermittelt und die Schallgeschwindigkeit unter Berücksichtigung der Lufttemperatur nach c/(m/s) = 331,5 + 0,6·T/°C (2)bestimmt. Die ermittelten Laufzeiten t lassen sich dann gemäß d = 0,5·c·t (3)in Abstände d umrechnen.At the earliest after a while t = 2d / c (1), in which mean:

d

the distance floor to the sensor and

c

the speed of sound,

the next sound pulse and measuring cycle are triggered. By the in the ultrasonic sensor 5 integrated temperature sensor 11 At the same time as the emission of the sound impulse, the air temperature T is determined and the speed of sound, taking into account the air temperature, is determined c / (m / s) = 331.5 + 0.6 * T / ° C (2) certainly. The determined transit times t can then be determined according to d = 0.5 · c · t (3) convert into distances d.

In the 2 B is the typical detection range of the ultrasonic sensor 5 shown. An acoustic cone is formed in the emission direction AR 6 which defines the area in which a safe recording of the biomass and morphological parameters of the plants is ensured. It has been shown that at an opening angle γ of the cone of sound 6 from 3 to 30 °, preferably 8 °, the sound waves reflected by the plants and soil can be detected exactly and allocated temporally or spatially.

At a distance A of the ultrasonic sensor 5 from the ground 8th for example, 2.5 m is the blind zone 12 of the sonic cone 7 significantly above the plant population 7 and the plants dive into the optimal measuring range 13 of the sonic cone 6 a, so that a sufficient accuracy in the measurement is reproducibly achieved. The blind zone 12 is the area of the sonic cone 6 in which no echo can be received as a result of transmitting the ultrasonic pulse.

The 3 shows the typical waveform of an ultrasonic echo EB for an unvegetated soil 8th and an ultrasonic echo EP for a plant population 8th with only a single sheet floor (1st floor).

At the uncultivated ground 8th comes from the entire backscattered signal of reflection on the ground 8th and therefore coincides with the ultrasonic sensor 5 one. In the present case, the maximum of the signal peak for the bottom echo is 9 ms, at a temperature of T = 20 ° C, a distance d between the ultrasonic sensor 6 and soil 8th of 1.55 m corresponds.

In the plant stock 7 a part of the sound wave is reflected at the foliage of the first floor and hits the ultrasonic sensor after 7 ms 5 one. The remaining part of the sound wave reaches the ground 8th and again hits the ultrasonic sensor after 9 ms 5 one. From the difference in transit time of the two echoes EB and EP of 2 ms, the height of the leaf floor of the plant population can be determined 7 above the ground 8th to 0.35 m. Typically, in advanced plant stocks 7 not just a local maximum in the course of the Pflan but several, generally up to 5. These echoes thus give the stratification of the leaf layers in the crop 7 again.

Basically, the recipient is 10 of the ultrasonic sensor 5 an echo on like in the 3 is shown. For example, the ultrasonic sensor used here 5 of the type P42-A4M-2D-K130E from the company PIL sensors GmbH, Erlensee, Germany, this analog signal is, however, compared with the aid of an integrated comparator with a predetermined threshold and provided only a binary information that falls only between "threshold below" and "Threshold exceeded" is different, so that results in echograms, as in 6 are shown by way of example.

To carry out the method according to the invention are the ultrasonic sensors 5 - as 4 shows - to a processor unit 14 connected, consisting of an electronic control device 15 for the ultrasonic sensors 5 and from a signal and evaluation unit 16 to process the measured values. To the signal and evaluation unit 16 is a GPS receiver 17 connected to the readings of the ultrasonic sensors 5 to link with position information or other positional foreign data. The current measured data is monitored by a monitor 18 the signal and evaluation unit 16 displayed continuously. Optionally, an electronically controllable dispensing unit 19 , For example, a field sprayer, to the signal and evaluation 16 be connected in dependence on the currently determined measurement results of the ultrasonic sensors 5 to vary the amount of means of production, for example growth regulators and / or fertilizers and / or pesticides and / or water. The determined measurement results for the plant stock 7 be in a data store 20 and can be used for further external processing for application recommendations, as well as for mapping and calibration purposes.

The course of the method according to the invention is in the 5a and 5b shown.

The drive device 15 triggers on all n ultrasonic sensors 5 simultaneously a sound impulse. At the same time, a timer with a defined time step, for example 1 μs, is started. In a loop then each ultrasonic sensor per time step 5 once queried and the state recorded. In the ultrasonic sensor type used here, this is a binary value 0, if no echo was registered at the time, or the value 1, if one above that of the ultrasonic sensor 6 predetermined threshold lying reflection signal was received.

After 20 ms, ie 20000 values, the loop is ended and the result (echograms) on an output interface of the drive device 15 for the signal and evaluation unit 16 placed. The steps described are repeated continuously every 50 ms.

The 6 represents, for example, such an echogram. It shows at unbewachsenem soil 8th an echo and a plant stock 7 several, typically 2 to 5, echoes coming from the different floors of the crop 7 come. If the plant stock 7 not too dense, the last echo always comes from the reflection of the sound wave on the ground 8th ,

The echograms generated in this way are transmitted by the signal and evaluation unit 16 received on the interface. The signal and evaluation unit 16 operates at a repetition rate of 1 Hz, so that a total of 20 echograms per ultrasound sensor per cycle 5 for processing at the signal and evaluation unit 16 queue.

In the signal and evaluation unit 16 the echograms are first calibrated, ie converted into distances via the speed of sound c. Because of the temperature dependence of the speed of sound, the air temperature of the temperature sensor 11 in the ultrasonic sensor 5 measured and taken into account. In a next step, obviously erroneous echoes, such as echoes, which come from a much greater distance than the mounting distance between ultrasonic sensor 6 and soil 9 matches or echoes coming out of the blind zone 12 of the sonic cone 6 come, removed.

The next step is to determine the distance between the first rising edge and the last rising edge for each of the remaining echograms. This distance corresponds to the height of the top sheet level above the ground 8th , Subsequently, the maximum of these values is determined over a maximum of 20 individual measurements.

After smoothing by median formation over the maxima of the last processed three cycles, a measurement signal is available, from which the absolute biomass information is determined. For this, the farmer has to specify a few calibration parameters such as crop, variety and stage of development. The determination of the biomass then takes place on the basis of previously determined, in the memory of the signal and evaluation unit 16 stored calibration functions, such as in 7 are shown.

The biomass signal is displayed on the monitor 18 the signal and evaluation unit 16 displayed and together with those from the GPS receiver 17 provided position information and / or foreign data in the data memory 20 saved for later evaluation and mapping. It goes without saying that the originally recorded echograms are also included on the data memory 20 be stored to allow a downstream evaluation with possibly other algorithms.

The biomass signal obtained can optionally also be used to attach one to the towing vehicle 1 coupled dispensing unit 19 as a sprayer o. The like., To control and z. B. growth regulators specific to the site on the plant population 7 deploy. For this purpose, an application recommendation is determined from the biomass signal by means of situation-dependent calibration functions.

Example 2

In addition to biomass, other morphological parameters of the plant population 7 , in particular the leaf position, the number of leaf layers and the vertical distribution of biomass in the plant population 7 to be determined.

The sequence of the method according to the invention corresponds to that of the example 1 , Only the evaluation of the echograms is changed.

Even if only one binary echogram is output per individual measurement as a result of the threshold value formation, the in 3 reconstructed original waveform when the ultrasonic sensor 5 about the plant stock 7 moved and several, for example 20 to 100 individual measurements are summarized. For this purpose, it is determined with which frequency at a certain point, ie distance from the ultrasonic sensor 5 a signal occurs. The determined frequencies are plotted in a histogram.

Examples of such histograms show the 8a to 8c , Histograms were recorded from three wheat stocks of the same variety (Batis), 8a ), middle ( 8b ) and lower ( 8c ) Amount of nitrogen were fertilized.

• – die Pflanzenhöhe als Differenz der Distanz zwischen dem ersten und dem letzten (Boden) Peak,
• – die Höhe ggf. vorhandener weiterer Blattetagen als Distanz zwischen den folgenden Peaks und dem letzten (Boden) Peak,
• – die Anzahl der Blattetagen als Anzahl der Peaks zwischen dem ersten und dem letzten (Boden) Peak,
• – die relative vertikale Verteilung der Biomasse im Pflanzenbestand als relative Häufigkeit in der Höhe h über dem letzten (Boden) Peak,
• – die gesamte Biomasse (Trockenmasse) als Verhältnis zwischen der Fläche unter den ersten Peaks und der Fläche unter dem letzten (Boden) Peak.

The following parameters can be determined from the histograms:

• The plant height as the difference of the distance between the first and the last (ground) peak,
• The height of any further sheet layers as distance between the following peaks and the last (ground) peak,
• The number of sheets as the number of peaks between the first and the last (bottom) peak,
• - the relative vertical distribution of the biomass in the plant population as relative abundance in height h above the last (ground) peak,
• - the total biomass (dry matter) as the ratio between the area under the first peaks and the area below the last (ground) peak.

Out The histograms are still visible, as the plant height and the Decrease biomass with decreasing fertilizer intensity and the peaks shift accordingly or change their expression.

The 8d shows a histogram of another wheat variety (Drifter), which was taken at the same time under otherwise identical conditions with maximum nitrogen. The slightly lower stature height of h = 0.73 m instead of h = 0.82 m and the changed expression of the peaks of underlying leaf layers can be seen.

Claims (11)

Method for the non-contact determination of the biomass and morphological parameters of plant stands, in which the plants of the stand are acted upon by a sound field emitted by an ultrasound source fastened on a mobile carrier during the passage; the sound echoes reflected by the plants and the ground are fixed by a support fixed to the support Receivers are detected and passed from this after conversion into digital signals to an evaluation and signal processing unit that currently evaluates the signals stored on a disk and displays on a monitor, optionally in an electronically controlled application unit, the signals to control commands for spreading of production resources are processed, wherein the sound field is guided substantially vertically to the ultrasonic source and at a significant distance over the stock, immerse the plants in an optimally effective measuring range of the sound field, and the Ultraschallqu cyclically sends sound pulses to the stock, the sound pulses being reflected at different depths of the stock foliage and possibly from the ground sequentially in spatially assignable n-echoes, and these echoes after decoding to a measure of the current biomass whose vertical Distribution in the stock and the morphological parameters of the stock, characterized by the following steps: a) cyclic irradiation of the plants of the stock by triggering sound pulses from at least one ultrasonic source with a sound frequency of 30 to 300 kHz and a maximum pulse duration of 500 μs, the time interval b) simultaneous measurement of the air temperature for the purpose of determining the temperature-dependent sound velocity, c) starting a timer with a defined time step simultaneously with the triggering of the sound pulses according to step a), wherein in a Loop at each time step the currently reflected echo is detected as a measured value at the receiver, d) stopping the timer by terminating the loop according to step c), summarizing all acquired measured values per time step in an echogram and transfer to an interface for the evaluation and signal processing unit, e) continuously repeating the steps c) and d) for supplying the echograms via the interface to the evaluation and signal processing unit, f) reading out and calibrating the echograms with consideration of the temperature according to step b), g) determining the biomass and / or the morphological parameters of the plant population as a function of the crop, variety and stage of development of the plants from the results according to step f) and optionally h) Determining the yield of production means taking into account external data such as application recommendations, crop and variety, developmental stage, dosing and Medium data, meteorological data, special conditions at depressions, crests or forest edges of the blow. Method according to claim 1, characterized in that that erroneously received echoes, in particular those echoes that outside of the distance ultrasonic source ground are present or those from one come to short distance, be removed. Method according to claim 1, characterized in that that the plant stock to be measured at an angle of less 10 ° to the Nadir is sonicated. Method according to claim 1, characterized in that that the plant to be measured at a distance of 2 to 4 m is sonicated. Method according to claim 1, characterized in that that the external data is stored position-specifically on a card are provided and with the help of a connected to the signal and evaluation unit GPS receiver become. Method according to claim 1, characterized in that that as morphological parameters the number of sheets, the Leaf position, uniformity of the growth and the vertical distribution of the biomass in the stock be determined. Method according to Claims 1 to 6, characterized that as a source of ultrasound and receiver, a sensor with a for Transmitting and receiving sound signals conventional ultrasonic transducer is used. Method according to Claims 1 to 7, characterized that uses a plurality of spaced apart ultrasonic sensors whose sound cones do not influence each other. Method according to claims 1 and 8, characterized that for all ultrasonic sensors a common timer is used. Method according to claims 1 and 8, characterized that for Each ultrasound sensor uses a separate timer. Method according to claim 1, characterized in that that as a means of production growth regulators and / or fertilizers and / or fungicides and / or pesticides and / or water be used.