Effet à long terme des engrais organiques sur le rendement et la fertilisation azotée des cultures (original) (raw)

Consequences of the use of different organic fertilizers (green manure, cereal straw, manure at 35 and 70 t/ha every 3 years and cattle slurry at 60 m3/ha every 3 years) and mineral fertilizer (four doses nitrogen) are tested in Changins since 1976. This study analyses the long-term effect (34 years) on crop yield, the need for nitrogen fertilizer and the stock of mineral nitrogen (N) in the soil. When N is not limiting, organic fertilizers have have different effects on grain yield. The year of organic input and the subsequent years, manure and slurry increase yields compared to the control without organic fertilizers, while green manure and systematic restitution of the cereal straw decrease it. However, on average over the past 34 years, these effects remain weak. On the contrary, when nitrogen is limiting, all forms of organic fertilizers have a positive long term effect on crop yields. The direct effect of organic fertilizer (first year of field application) may be positive or ...