Farms have been able to draw initial conclusions after the first crop growing season subject to the new Fertiliser Ordinance. For example, N fertiliser quantities were at their usual level in many cases, despite the fact that fertiliser requirements were mandatory. The Nmin values measured in the spring of 2018 were generally so low that the amount of N still to be fertilised only need to be adjusted slightly downwards. Nitrogen is thus unlikely to be the limiting factor for possible declines in yields during the year. In retrospect, this was a good year to "practice" with the new specifications in the Fertiliser Ordinance as there was virtually no need to deviate from existing fertilising practices.
The top priority must be to ensure yield stability from locations, both now and in the future. This will not work using fertilisation with nitrogen alone, because there will also be years when the permitted N amount is significantly lower in individual cases – be it due to higher Nmin values or farm-specific combinations (preceding crop, manure fertilisation, etc.). It is extremely important that soil fertility in locations is appropriate to extenuate these "nitrogen gaps". Tools which can be used to increase and/or maintain soil fertility are commonplace measures such as tillage, catch crop cultivation, crop rotation and straw management to name just a few. However, the most effective lever still is balanced fertilisation. It is crucial that all nutrients are treated in equal measure. In this context, the basic idea of the Liebig’s barrel still provides the basis for the good professional practice in the field of fertilisation and it is more essential than ever to take his concept into account today.