Long-Term Field Experiments with Fertilizers in Romania: Their Relevance to Sustainable Agriculture

Abstract

Long-term field experiments are indispensible for understanding, proving and monitoring changes in soil fertility resulting from many years of husbandry, especially from fertilization. Because they are long-term, they are costly to maintain but their scientific and practical information cannot be replaced by other means – and their value keeps on growing. The longest-running continuous experiments, now 169 years old, were established at Rothamsted, in England, by Lawes and Gilbert in 1843 to investigate issues of nutrient cycling that could only be resolved by experiment. Experimentation in Romania has also focused on long-term field experiments. Systematic trials were established 46 years ago in 15 locations with different soil and climatic conditions, and long-term experiments of more than 46 years are continuing at eleven sites. These experiments comprise a geographic network spanning different soil and climatic conditions with a unique design to track the evolution of differential soil fertility and the impact of fertilizers on the environment. First of all, the results characterize their particular sites. More than this, they focus attention on universally valid, surprisingly actual, cause-and-effect relations, and they help greatly to reconcile ecological and economic interests and to clear up real issues of environmentally friendly nutrient supply and sustainable husbandry.