Long-term experiments are indispensable for investigations on the long-term effects of various crop production methods and technologies. The long-term experiments set up in Martonvásár by Béla Győrffy are now 50 years old and can be considered as part of the national heritage. The most important of these experiments involve crop rotation vs. monoculture trials, the comparison of fertilisation systems, studies on the interactions and carry-over effects of organic and mineral fertilisers, fertiliser rate experiments and polyfactorial experiments. The long-term experiments in Martonvásár form an integral part of maize and wheat research and provide a place for testing the agronomic responses of maize hybrids and wheat varieties. Valuable scientific results are obtained from these experiments regarding the reasons for yield depression in monocultures, the yieldincreasing effect of crop rotations, the comparative benefits of organic and mineral fertilisation, the agronomic responses of genotypes, the sustainability and yield stability of crop production techniques, and the interaction between various crop production factors. These results promote the improvement of maize and wheat production and are regularly incorporated into recommendation systems. The present generation of scientists has a responsibility to maintain these experiments, so that they can continue to serve their purpose in the coming decades.