Long-term effect of different forms of organic amendments on soil properties, nutrient availability to agricultural crops, yield, and harvest quality.
The consequences of the use of different organic and chemical amendments have been tested at Changins since 1963. Their long-term effects on soil properties, crop yield, nitrogen fertiliser requirement and soil mineral nitrogen reserves were studied in 2009 and 2014.
The results of these studies have shown that
- taken individually, the conventional soil conservation practices tested do not ensure the maintenance of organic matter (MO) content in the tilled soils of this study;
- SIMEOS-AMG is the humus balance model that best simulates the effect of the processes on the evolution of C stocks;
- organic fertilisers have had a substantive positive effect on microbial activity and biomass, and would appear to modify the composition of the latter; and
- when nitrogenous fertilisation is non-limiting, organic fertilisers have effects that are contrasting (positive for farmyard manures, negative for green manures and straw) but of little importance for crop seed yield.
Research activity is ongoing, and focuses on the characterisation of the effects of the processes (organic and/or chemical) on soil physical and hydrological properties, as well as on the quality of soil organic matter and the microbial community.