HU188363B - Method for loval meassuring soil moisture - Google Patents

Abstract

Field of the Invention The present invention relates to a method for measuring soil moisture in situ, wherein a unit of a sample of soil having a known average weight is placed in a calibrated volume vessel. The essence of the invention is that the sample sample vessel is continuously filled with water from a calibrated liquid dispenser, the soil sample is pulverized by stirring, air bubbles are removed and the moisture of the soil sample is determined by measuring the volume of water added during filling. Figure I -1-

Description

FIELD OF THE INVENTION The present invention relates to a method for measuring soil moisture in situ by placing a unit amount of a sample of soil of known average weight in a volumetric calibrated flask.

It is known that measuring the soil's current humidity is a prerequisite for efficient agricultural production, since only the optimum supply of plant water can be expected to produce the calculated, appropriate yield-increasing effect of other production factors (eg fertilization).

Knowledge of the soil's current moisture content is one of the basic parameters for crop production, land reclamation and agricultural water management.

Several methods have been developed for measuring soil moisture, which have more or less deficiencies. The most important prior art known solutions are as follows.

Soil moisture is determined by soil sampling in an oven. Its disadvantage is that it can be used only in the laboratory and the results of the measurement can be determined two days after the sampling of the soil.

Soil moisture is also measured by determining the electrical conductivity of the soil. It has the disadvantage that the salt content and physical characteristics of the soil can significantly distort the measured soil moisture value, and that it requires prior calibration.

The so-called. In the case of tensile meters of soil moisture, an amount proportional to the soil moisture potential is determined. Its disadvantage is that it can only be used in the so-called low tensile range of the soil (to the extent of the water capacity of the field).

In the case of neutron scattering moisture measurement, the measurement result is significantly influenced by the presence of low atomic weight elements and the structure of the soil. A further disadvantage of the procedure is that they can be installed in accordance with radioactive radiation protection regulations and require prior calibration.

The disadvantage of the γ-ray absorption method is that the structure and density of the soil greatly influences the measurement results, and that the procedure requires preliminary calibration.

In the case of capacitive soil moisture measurement, the measurement results are significantly influenced by the material quality, temperature, and salt content of the soil, and the measurement is performed by pre-calibration.

Measurement of the specific gravity of dry and wet soils is based on a laboratory procedure described in the "Rukovodstva k laboratomo practiceské zanjatijam p zemledeliju". They are described in a publication published in 1951. Specific gravity is determined using a pycnometer. The soil sample is decontaminated by boiling or by vacuum extraction treatment. The soil sample is dried in a laboratory oven and cannot be used in the field.

All of these procedures can be implemented with significant labor and expense, and measurement results are usually recorded after days.

It is an object of the present invention to overcome the above shortcomings, that is, to improve the process for measuring soil moisture on the spot, which is characterized by significantly better efficiency than known solutions.

The invention is based on the discovery that the object of the present invention is solved by measuring the soil moisture in the field under field conditions by determining the free (anhydrous) pore space of the soil sample.

SUMMARY OF THE INVENTION The object of the present invention in the field soil moisture measurement method described hereinabove is to fill the sample container with water from a calibrated liquid dispenser by continuously mixing the soil sample, removing air bubbles, and measuring the moisture content of the soil sample.

It is expedient to implement a method of determining the moisture content of the soil sample by measuring tables.

The process of the present invention will now be described, by way of example, with reference to a drawing (FIG. 1) for better understanding.

A sample taken from the soil using a soil sampler is weighed on a scale (100 g) and placed in a measuring flask (3). From the liquid dispenser 1, previously filled with water, the measuring vessel 3 containing the soil sample is continuously worked up to about half of the soil sample by agitation and the air bubbles are removed. As soon as the soil sample has been bubbled ("bubble beading" is removed), a bell-shaped, upwardly tapering, bell-shaped, top-open top is placed on the graduated wide-mouthed measuring flask. From the liquid dispenser 1, 2, sufficient water is discharged into the measuring vessel 3 to reach the level mark of the upper part of the measuring vessel 3.

Read the amount of water consumed during the filling process on the scale of the liquid dispenser 1, 2.

Depending on the water level (the single independent variable) of the liquid dispenser, the soil moisture can be determined directly from the calibration curve supplied with the equipment.

The moisture content of the soil sample can be calculated as follows:

^Υ ' ^(Κ Α ^ Χ) Ε- ^{Ι) 1θθ} · ^1ΐ1 '^{<> 1}

Y = the moisture content of the soil sample as a percentage by weight,

A = weight of soil sample (g), determined quantity 100 g

C = volume of the measuring vessel (cm ³ ), known

E = specific gravity of water (0,998 g / cm ³ at 20 ° C)

X = volume of water required to fill 3 measuring flasks containing soil sample (cm ³ )

The measurement method of the present invention took into account that the determination of the specific gravity of a large number of representative soil samples provides a good approximation of the average soil specific gravity.

No. 1 Table 1 shows the magnitude of error in soil moisture values assuming a single average soil weight. The specific gravity of water was also considered constant, since its temperature dependence is negligible.

j 188 363

No. 1 With the mean values given in Table I, the error in calculating the specific gravity values of the soil moisture values measured by the method according to the invention can be calculated.

The error resulting from the calculation of the estimated average specific gravities is less than 4%, ie it is within the error of the commonly used soil moisture measurement procedures.

Measurement tables ¹⁰ used in the process according to the invention in an equation used in the "Y" to be assembled. In the context used, the parameters K, A, C, E are known, i.e. it is a one-variable function that depends on the amount of water (X) required to fill the measuring vessel. ¹⁵ For each soil type (sand, clay, clay) that can be identified in the field - the given i nomograms, knowing the value of X, the soil moisture content can be read directly.

The accuracy of the determination is determined by the deviation of the K value from the true ² θ, which is treated as a measurement error.

Table 1

Correction of measured soil moisture values depending on soil specific gravity.

Soil Moisture content (% by weight)

An advantage of the invention _is that it allows simple, fast and sufficiently accurate determination of the weight percentage of soil moisture in the premises. The process of soil salinity is ⁵ today. not sensitive to temperature, structure, can be used in the whole soil moisture range. and Preventive Laboratory Calibration Not Required Depending on the sampling technique, it can be used to determine not only surface moisture but also soil profile.

Claims (2)

Patent claims A method for measuring soil moisture on the spot, wherein a unit volume of a sample of soil of known average weight is placed in a volumetric calibrated flask, characterized in that the flask containing the sample is continuously filled with measured. 2. The method of claim 1, wherein the moisture content of the soil sample is determined by tabulation. specific gravity in g / cm ³ 0 10 20 30 2.50 -3.7 -4.0 -4.3 -4.7 2.55 -2.4 -2.6 -2.9 -3.1 2.60 -1.2 -1.3 -1.4 -1.5 2.65 - - - - 2.70 + 1.1 + 1.2 + 1.3 + 1.4 2.75 + 2.2 + 2.4 + 2.6 + 2.8 2.80 + 3.2 + 3.5 + 3.8 + 4.1 1 page drawing Published by the National Office of Inventions Responsible for publishing: Zoltán Himer, Head of Department Picked up by the Printing Industry (877699/09) 88-0645 - Dabasi Nyomda, Budapest - Dabas Director: Csaba Bálint Director