RU2281644C9 - Method for evaluating yield of cereal crops depending on weather conditions - Google Patents

Abstract

FIELD: agriculture, in particular scientific investigations for evaluation of agricultural lands and results of employment thereof in agricultural production.

SUBSTANCE: method involves setting measurement period throughout vegetation of cereal crops beginning from sowing to temporary point lying within the boundaries from earing phase to mature yellow phase; dividing measurement period into time intervals not in the excess of decade; during said time intervals measuring soil moisture content and air temperature; determining, on the basis of obtained measurement results and preliminarily set minimal and optimal measured values, for each of time intervals relative value of effective moisture content of soil and relative existing air temperature value, as well as total yield loss values resulted from combined action of both measured factors. Given results make base for determining yield and allow this yield to be calculated from cited formula. Indicated yield calculation formula provides means for determining combined action of a number of factors during each individual time interval. Final evaluation of cereal yield is provided by summing up intermediate results of each of time intervals.

EFFECT: increased precision and enhanced reliability in evaluating cereal yield.

1 dwg, 1 tbl

Description

The invention relates to the field of agriculture, in particular to the field of scientific research in the assessment of agricultural land and the results of their use in agricultural production.

A known method of comprehensive assessment of the level of fertility. (Methodological recommendations and regulatory materials for the development of adaptive landscape farming systems in the south of Central Siberia - Abakan. 2003. - S.8-9). This method has the potential to assess yield, and its essence is expressed by the following two formulas:

where PORP _i is a generalized indicator of the availability of fertility resources;

Hp _i is the i-th fertility parameter, which is calculated according to the form below;

n is the number of fertility indicators.

where P _mi is the minimum value of the i-th indicator of soil fertility;

P _oi is the optimal value of the i-th fertility indicator;

P _ti is the current value of the i-th fertility indicator;

A _i - correction factor.

The advantage of the proposed method is the ability to operate with the necessary number of factors, however, its implementation on the principle of a simple summation of the effects of various factors does not accurately reflect the ongoing processes. The following disadvantages also lead to an increase in the error: the change in the level of influence of the factor in different phases is not taken into account, the well-known fact of a higher influence of the limiting factor is ignored, and the change in factors over time is not taken into account.

Closest to the proposed technical solution, the prototype is a method for assessing plant productivity depending on the limiting factor of plant life (Lebedev N.S. Law of the limiting factor: application in agriculture // Agriculture. - 1994. - No. 6 - P.9-11 )

Plant productivity is determined by the following expression:

where Y is the productivity of the plant;

x is the actual parameter (limiting) of a particular plant life factor;

a is the optimal parameter of this factor;

b is the minimum or maximum parameter of the same factor;

A - maximum plant productivity.

This technical solution has a low accuracy of the results for the following reasons: the lack of consideration of the influence of any non-limiting factor, does not take into account the change in factors over time and does not take into account the different effects of individual phenophases on productivity.

The objective of the claimed technical solution is to increase the accuracy and reliability of estimates of yield of grain crops.

This problem is solved in that in order to assess the yield of grain crops depending on weather conditions, the ratio of the difference between the measured current and minimum values of weather factors to the difference between the optimal and minimum values of the same factors is determined, while the measurement period is established during the growing process of crops from the beginning of sowing to a time point located in the range from the earing phase to the yellow ripeness phase, the measuring period is divided into time intervals not exceeding a decade, n and these time intervals measure the average values of air temperature and soil moisture, the assessment of the yield of grain crops is carried out according to the formula below

where Y is the yield estimate, kg / ha;

U _max.z - maximum crop yield for the analyzed land, kg / ha;

n is the number of time intervals included in the measurement period;

K _φ is the coefficient corresponding to the phenophases of plant development;

α ₁ , α ₂ - the degree of action of weather factors;

K is a coefficient taking into account the distinctive effect of temperature;

W _i - the average value of soil moisture in the i-th time interval,%;

W _min - the minimum value of soil moisture, ensuring the vital activity of plants,%;

W _oi is the optimal value of soil moisture in the i-th interval,%;

t _i - average value of air temperature on the i-th interval, ° С;

t _min - the minimum value of air temperature for the life of plants, ° C;

t _oi is the optimal value of air temperature on the i-th interval, ° C;

C is the coefficient that compensates for the part of the growing season, which was not included in the measuring period, kg / ha.

The claimed technical solution differs from the prototype in that a measurement period is established during the growing process of crops from the beginning of sowing to a time point located in the range from the earing phase to the yellow ripeness phase, the measurement period is divided into time intervals not exceeding a decade at these intervals time measure the average values of air temperature and soil moisture, the assessment of the yield of grain crops is carried out according to the formula below

where Y is the yield estimate, kg / ha;

U _max.z - maximum crop yield for the analyzed land, kg / ha;

n is the number of time intervals included in the measurement period;

K _φ is the coefficient corresponding to the phenophases of plant development;

α ₁ , α ₂ - the degree of action of weather factors;

K is a coefficient taking into account the distinctive effect of temperature;

W _i - the average value of soil moisture in the i-th time interval,%;

W _min - the minimum value of soil moisture, ensuring the vital activity of plants,%;

W _oi is the optimal value of soil moisture in the i-th interval,%;

t _i - average value of air temperature on the i-th interval, ° С;

t _min - the minimum value of air temperature for the life of the plant, ° C;

t _oi is the optimal value of air temperature on the i-th interval, ° C;

C is the coefficient that compensates for the part of the growing season, which was not included in the measuring period, kg / ha.

A method for assessing the yield of cereal crops, depending on weather conditions, we consider the example of wheat. Depending on the required time for obtaining an estimate of yield and accuracy of the result, a measurement period is selected as part of the growing process and divided into time intervals not exceeding a decade, at which average soil moisture and air temperature are measured. At the same time, the beginning of the measuring period always remains constant and corresponds to the beginning of sowing, and the end of the measuring period is variable and, depending on the above conditions of accuracy and time before harvesting, it is set within the boundaries from the earing phase to the yellow ripeness phase. The part of the vegetation process that is not included in the measurement period is taken into account by introducing the constant C, which is calculated from climatic data and can be determined in advance.

For each time interval, based on the obtained measurement results and previously established minimum and optimal values of the measured values, the relative value of the productive moisture of the soil and the relative effective value of the air temperature, as well as the total yield loss from the combined action of both measured factors, are calculated. The total yield loss due to deviation of the actual values of weather factors from their optimal values is determined by the following expression:

All letter designations in this and the following formulas are the same as in the above formulas. The K coefficient in this expression takes into account the distinctive level of influence of air temperature on the crop. With the same relative deviation of both factors - humidity and air temperature from their optimal values, the deviation of air temperature leads to lower yield losses, namely, in accordance with the value of the entered coefficient K.

Estimation of wheat yield is calculated by a weighted summation of the intermediate results for each time interval in accordance with the formula below

Weight coefficients K _φ (corresponding to phenophases of plant development) take into account the different effects of phenophases on crop formation. To do this, a table of coefficients K _φ is compiled, where each phenophase is assigned a specific value (for example, for the phenophase 1 - “Shoots” K _φ = 0.7) and the numbers of those time intervals during which the development of plants of this phenophase is realized. All constant parameters of the calculation formula for each culture have specific values. For crops, these parameters are in the following limits: K _φ = (0.6 ÷ 2.0); α ₁ , α ₂ = (1.2 ÷ 1.4); K = (0.36 ÷ 0.39). The most suitable time interval is 3-5 days, often a decade is used. The maximum yield is calculated according to the equation of the proposed method when using the actual yield and weather parameters of the previous year or several previous years.

To clarify the physical nature of the proposed computational formulas, we note the following. From the analysis of existing practical results it was found that the deviation of soil moisture and air temperature from their optimal values leads to yield losses. And to take into account the combined influence of these weather factors, it is necessary to add the resulting losses geometrically, like vectors. That is, the total yield loss is equal to the square root of the sum of the squares of the component losses. This approach is consistent with the conclusions about the action of the limiting factor, which is clearly demonstrated by the graphical construction in the drawing. From the above illustration it is seen that the total loss P _Σ determines the loss of the limiting factor, in this case it is a factor that has losses P ₁ . The proposed option analytically describes not only those cases where one factor has a limiting effect, but also all other possible cases.

In support of the implementation of the task of the claimed technical solution in the form of increasing the accuracy and reliability of estimates of the yield of grain crops, the following explanations should be given. Weather factors have a nonlinear effect on the production process, so the use of large time intervals for measurement, which significantly manifests non-linearity, leads to large errors. Using a measuring period with a variable end point allows you to get an estimate of productivity with the necessary temporary stock before harvesting. But at the same time, setting the end of the measurement period to an earlier time point leads to a decrease in accuracy, since accurate weather data are taken into account in the measurement period, and the rest of the vegetation process is estimated by climatic data. The table shows the results of calculating the yield of the proposed method and the actually obtained yield of spring wheat in the Elite farm of the Novosibirsk region.

Table Estimated and Actual Spring Wheat Yields Year Estimated yield, kg / ha Actual productivity, kg / ha 1987 45.7 46.3 1980 39.3 38,2 1983 27.3 28.3 1981 21,4 20.8

To assess the yield, weather indicators of the weather station Ogurtsovo in the Novosibirsk region were used. The measuring period was the time interval from the inoculum phase to the wax ripeness phase. From the table it can be seen that taking into account weather conditions in accordance with the proposed method allows you to get an estimate of yield with accuracy, providing the possibility of its use for scientific and industrial purposes.

Claims (1)

A method for assessing crop yields depending on weather conditions, including determining the ratio of the difference between the measured current and minimum values of weather factors to the difference between the optimal and minimum values of the same factors, characterized in that a measurement period is established during the growing process of crops from the beginning of sowing to temporary points between the heading phase and the yellow ripeness phase divide the measurement period into time intervals not exceeding a decade, per s time intervals measured average values of temperature and soil moisture estimation yields of crops is performed according to the formula

where Y is the yield estimate, kg / ha; U _max.z - maximum crop yield for the analyzed land, kg / ha; n is the number of time intervals included in the measurement period; K _φ is the coefficient corresponding to the phenophases of plant development; α ₁ , α ₂ - the degree of action of weather factors; K is a coefficient taking into account the distinctive effect of temperature; W _i - the average value of soil moisture in the i-th time interval,%; W _min - the minimum value of soil moisture, ensuring the vital activity of plants,%; W _{oi is the} optimum value of soil moisture at the i-th interval,%; t _i - the average value of air temperature on the i-th interval, ° C; t _min - the minimum value of air temperature for the life of plants, ° C; t _oi is the optimal value of the air temperature on the i-th interval, ° C; C is the coefficient that compensates for the part of the growing season, which was not included in the measuring period, kg / ha.