Understanding nitrogen use efficiency (NUE) of crops plays an important role in achieving
sustainable production. Intensive agriculture has adversely affected social and environmental issues
worldwide over the past few decades. Anaerobic digested residues from the distillery industry
(DADRs) can be used in agriculture, thereby recycling valuable organic materials that can supply
organic N. An experiment using DADRs in horticulture was conducted to evaluate the performance
of different treatments on yield and NUE. The experiment was conducted for five years, growing
lettuce, cauliflower, chicory, potato, Swiss chard, catalogna chicory, tomato, pepper, and melon in
two different succession schemes. Five fertilization treatments were designed, including a mineral
fertilization control, in which nitrogen (N) was supplied according to standard recommendations in
the area. The other treatments were an unfertilized control and three treatments in which 50%, 75%,
and 100% of the N were supplied by DADRs and the remaining with common chemical fertilizer.
Major findings were: (1) Spring–summer crops showed the lowest N-uptake and N recovery, during
this period high chemical fertilization can cause environmental problems such as N leaching, and
fertilization with 100% DADRs is a viable alternative; (2) fall–winter crops can be fertilized by
combining 50% mineral N and 50% organic N, supplying the nutrients required by the crops during
the growing cycle.
