One of the ways to increase the efficiency of crop production is to maximize the genetic potential of agricultural crops. To do this, it is necessary to create the most favorable, ideal conditions for the growth of plants. At all stages of growth and development of plants there are their own indicators, which should be ideal (optimal). (Research purpose) The research purpose is in developing an algorithm for calculating the parameters of an ideal field on the example of differential fertilization. (Materials and methods) Authors have used mathematical modeling using three basic concepts: responsiveness functions, the digital double of the agroecosystem (field), and the ideal field. The article presents the comparison of the parameters of the real field with the ideal one using a digital double of the real field. (Results and discussion) the parameters of the ideal field has been adjusted taking into account the parameters of the actual field based on the planned yield, requirements for agricultural technology, the used optimization criterion (the target function), and restrictions. In order to make optimal management decisions, along with the agrotechnical requirements for the cultivation of a particular crop, it is necessary to specify the parameters of the ideal field, which must be achieved in the actual field. The article presents the procedure for calculating the ideal field parameters using the example of solid mineral fertilizers. (Conclusions) The article presents an algorithm for calculating the optimal doses of differentiated fertilizer application based on the digital double of a specific field. The dose values are used to refine the parameters of the ideal field and adjust it during the growing season. The algorithm can be used to make optimal management decisions on differentiated seeding, tillage, and the use of plant protection products. As data on the state of soil, plants and knowledge base are accumulated in the form of plant responsiveness functions to certain agro-technical techniques, it is possible to increase the adequacy of the digital double of the actual field and obtain more reliable data for correcting the parameters of the ideal field.