Effects of Different Organic Fertilization Practices and Mineral Fertilization on Potato Quality

Abstract

ABSTRACT The short-term effects of different fertilization practices were the target of the three year series of experiments. The effects of organic fertilizers and a mineral fertilizer were investigated on selected quality characteristics of potato (Solanum tuberosum cv. Matilda). Chemical composition, new contemporary quality parameters, ‘change of electrical conductivity’ and ‘darkening of potato extract’, and a parameter of environmental quality were analysed to discover the qualitative effects of increasing rates of fertilizers (fresh and composted farmyard manure, aerated slurry and mineral fertilization). In contrast to farmyard manure, the high application rate of the mineral fertilizer raised the concentration of nitrogenous compounds (nitrate and free amino acids) in potato. The slurry fertilization caused a similar but smaller reaction. The potato dry matter content differed more strongly than starch between the organic and the mineral fertilizer and between the application rates. The minerally-fertilized potatoes showed a lower dry matter content than the organically-fertilized. Thus, the dry matter and starch yield showed no significant difference between the mineral and organic treatments, even though the fresh matter yield was higher with the mineral fertilization. The ‘change of electrical conductivity of potato extract’ was highest with the mineral fertilization and the difference between organic fertilizers widened with increasing fertilization levels. The concentrations of mineral compounds and vitamin C, and the ‘darkening of potato extract’, due to a strong variation between replications, showed only a few statistically significant differences between the treatments.