The importance of amino-N for humus formation studied by comparing amino-N input to the soil and soil total nitrogen content in long-term experiments

Summary

Humus formation is thought to depend directly on carbon input. Referring to earlier studies we tested the role of amino-bound nitrogen (amino-N) input to the soil using data of 10 long-term experiments with different fertilization and crop rotation treatments. In 8 out of the 10 experiments there was a significant positive correlation between the amino-N input and soil total N content. This correlation was much stronger than the one of total N input and soil N content, indicating that amino-N was more important for soil N accumulation than total N input. Amino-N from farmyard manure seems to be more effective in this respect than amino-N from other organic fertilizers.