V. P. Yakushev

Evaluation of Current State of Agricultural Land Using Problem-Oriented Fuzzy Indicators in GIS Environment

Current state of agricultural lands is defined under influence of processes in soil, plants and atmosphere and is described by observation data, complicated models and subjective opinion of experts. Problem-oriented indicators summarize this information in useful form for decision of the same specific problems. In this paper, three groups of problem-oriented indicators are described. The first group is devoted to evaluate agricultural lands with winter crops. Second group of indicators oriented for evaluation of soil disturbance. The third group of indicators oriented for evaluation of the effectiveness of soil amendments. For illustration of the methodology, a small computation was made and outputs are integrated in Geographic Information System.

Risk analysis as the basis for evaluating the consequences of climate changes in agriculture

A method is proposed for evaluating the consequences of climate changes in agriculture based on comparing the risk of major crop failures under current and anticipated climatic conditions. It is shown that risk is very sensitive to climate changes and can increase substantially against the background of relatively small decreases in the long-term average (normal) yield. The possibility of compensating the negative effect of an increase of risk by reducing the annual variability of crop yield is discussed. Calculation formulas are given.

Soil acidity adaptive control problem

Problem of soil acidity regularization is modeled as stochastic adaptive control problem with a linear difference equation of the dynamics of a field pH level. Stochastic component in the equation represents an individual time variability of soil acidity of an elementary section. We use Bayesian approach to determine a posteriori probability density function of the unknown parameters of the stochastic transition process. The Kullback–Leibler information divergence is used as a measure of difference between true distribution and its estimation. Algorithm for the construction of an adaptive stabilizing control in such a linear control system is proposed in the paper. Numerical realization of the algorithm is represented for a problem of a field soil acidity control.

Methodology and tools for analyzing on-site data in precision agriculture

It is suggested to use all possible statistical analysis methods and then a comparative analysis of the results to increase the reliability of management decisions in precision agriculture.

Identification of homogeneous zones on a field based on yield of individual plots

A method is examined and an algorithm is proposed for identifying relatively homogeneous zones on a given agricultural field based on yield on its individual small plots. The initial information is formed automatically by means of harvesting machines equipped with yield sensors and global positioning system (GPS).

Mathematical models and methods of realizing information technology procedures in precision agriculture

A software set for real-time formation of the information technology basis of realizing agrotechnical procedures in a precision agriculture system is examined.

Probabilistic model for determining possible yield level

On the basis of the methodology for stochastic modeling and long-term statistical data about spring wheat productivity obtained in comparative precision farming tests on the bioground of the Agrophysical RI, an approach to establishing the law of distribution of the actual possible yield of the farm crop in particular soil climatic conditions is considered. The knowledge of this law will make it possible to objectively determine the potential yield level on a given field and develop, on reasonable grounds, the respective individual technology with regard to yield value.

Adaptive management of environmental acidity

This paper proposes a new approach to the determination of doses of some meliorant for stabilizing the environmental acidity in an agricultural field through the application of optimal control methods in the presence of random disturbances. The acidity dynamics process is considered as a partially observable Markov process, and the Bayesian approach is applied.

Comparative analysis of expected changes of risk under favorable and unfavorable effects of changing climate on productivity potential

The given results of a methodological investigation show that, under favorable climate change accompanied by an increase in the average productivity potential of agroecosystems, the risks of poor crop years can often decrease to a considerably greater degree than increase in comparable situations under unfavorable climate change. This conclusion is based on an analysis of a probabilistic model interpreting yield as a random variable whose distribution depends on climate characteristics.

Theoretical basis of optimal choice of crop varieties

The solutions of two mathematical formalizations of the problem of the optimal choice of crop varieties are proposed. The maximum average yield for given distributions of the expected average yield of chosen crops or the maximum probability of exceeding a certain permissible level of the average crop yield for given probabilities of exceeding this level by existing varieties is taken as the optimality criterion of the agrometeorological conditions forecasted for a particular year.