A COMPUTERIZED PROGRAMME FOR FERTIGATION OF GLASSHOUSE CROPS
This paper presents a system with which recommendations can be made for the use of fertilizers as top dressings. The system is based on concentrations of N, S, P, K, Ca and Mg in the 1 : 2 volume extract. A standard nutrient solution is used, the composition of which differs among crops. The compositions of these standard nutrient solutions are adjusted compensating imperfections in the chemical composition of the soil extract. The concentration of the nutrient solution applied is assessed on the basis of the nitrogen concentration in this solution and in the soil extract. An outline of the calculations is presented.