Dynamic model of crops’ normalized difference vegetation index in central federal district environment

Abstract

The article describes a mathematical model which represents dynamics of the normalized difference vegetation index for winter wheat plantings in central black soil areas. As opposed to the approaches considered during our theoretical study, which, as a rule, are based on averaged data related to respectively vast territories (districts, regions, agricultural enterprises), this article describes a model which relates to rather small areas, namely to particular fields measuring 30-200 ha. The multiplicative model under consideration takes into account two opposite tendencies in the development of winter wheat: the process of phytomass increase and the process of plastic substances production. Parameters of the suggested model were estimated for winter wheat plantings in central black soil area on the fields with different levels of productivity for 2017 in accordance with normalized difference vegetation index data. We estimated the parameters by least square method. We performed model functional tests on the basis of the data received during remote sounding of the soil at more than one hundred of fields in Central Federal District. The test results are very promising. The suggested model allows for estimation of ripening period and the time of harvesting. The model can be applied for approximation of normalized difference vegetation index missing values, as well as for estimation of time required to attain maximum index value and, consequently, for forecasting of harvesting terms.