The article is devoted to application of portfolio analysis methods to solve problems related to the distribution of funds across different land endowment for growing crops. In the process of agricultural activity, the question of determining the share of participation in various farms often arises. If the net income from a farm is considered in probabilistic terms and it is assumed that the farmer is provided with a certain amount of land, the problem of choosing the optimal combination of farms can be interpreted as a special case of a problem of forming a securities portfolio. This article is directed to assess the applicability of the theory of portfolio analysis to the problem of agricultural diversification or, on the other hand, to study the conditions under which the only diversification strategy is implied for farmers who make decisions. Based on hypothetical data, an effective border of the feasible set of diversification strategies for two farms has been constructed. The possibility of application the separation theorem for agriculture has been considered and various options for the main objective of agricultural diversification have been analyzed.