Abstract
Data of the "Static Fertilisation Experiment Bad Lauchstädt" were used to identify the effect of different fertiliser application on yield, various energetic parameters as well as on carbon and nitrogen balance of the long-term trial in a selected time period (1991-2000). The fertiliser regimes considered, are neither mineral fertiliser nor farmyard manure (without/without), mineral NPK and no farmyard manure (NPK/without), no mineral fertiliser and 10t ha m 1 a m 1 farmyard manure (without/10), mineral NPK and 10t ha m 1 a m 1 farmyard manure (NPK/10), no mineral fertiliser and 15t ha m 1 a m 1 farmyard manure (without/15), as well as mineral NPK and 15t ha m 1 a m 1 farmyard manure (NPK/15). The farmyard manure was only applicated to root crops. The crop rotation included sugar beets, spring barley, potatoes and winter wheat. In most cases, the treatment NPK/10 yielded in the most favourable results whereas the treatment without/without was the most unfavourable one. Sugar beets were - followed by winter wheat - the most profitable crops, potatoes the most unfavourable one. The fossil energy input was highly variable; it ranged from 4.1 to 24.3GJ ha m 1 a m 1 depending on fertiliser regime and crop. The total yield (based on main products and by-products) varied from 2.1 to 20.1t dry matter ha m 1 a m 1 , corresponding to an energy output between 3.4 and 33.6GJ ha m 1 a m 1 . The energetic parameters energy gain (net energy output) and energy intensity ranged form 25.5 to 315GJ ha m 1 a m 1 and from 143 to 1824MJ GE m 1 , respectively. The carbon balances resulted the highest C gain with the exclusive mineral fertilisation (NPK/without), followed from the treatment NPK/10. The same applies for the nitrogen balances.