The CAP Health Check introduces a set of support measures to assist vulnerable agricultural sectors, with the aim of minimizing the effects of the implementation of total decoupling payments in less competitiveness sectors. This paper analyzes the impact of a support program for rain-fed agriculture, through the National Plan for Encouragement of Crops Rotations. The case study is focused on Castilla y León (Spain) rain-fed agriculture. The simulation results based on Positive Mathematical Programming technique for each farming district analyzed, reveal the influence of the traditional crops rotations in the analyzed areas to adhere to the National Plan for Encouragement of Crops Rotations. The analysis of the results allow us to conclude that there is need for simplification of the mechanisms designed to carry out this program, bearing in mind that the support efficiency in many cases is limited.