USE OF SIMPLEX-LATTICE DESIGN TECHNIQUES TO DETERMINE OPTIMUM DISTRIBUTION OF FERTILIZERS BETWEEN TIMES OF THEIR APPLICATION

When optimizing amounts and times of fertilizers application, two different problems have to be solved: optimal amounts of fertilizers have to be determined as their total amount is gradually increasing, and optimal distribution of this amount has to be found between several times of its application. The first problem was approached by numerous investigators and is fairly well studied. This paper is devoted to the second problem - to determine the optimal distribution of the known amount of fertilizers between the times of its application. Applying fertilizers on more than one occasion is important for crops with a long growing period and the best strategy for fertilizing is to relate applications to specific soil and climate conditions. According to our investigations, this problem can be best solved by using data from experiments based on a simplex-lattice design. This approach also enables the number of experiments to be decreased to substantially reduce the time for the investigations.