Distillery Anaerobic Digestion Residues as Fertilizers for Field Vegetable Crops: Performance and Efficiency in Mid-term Successions

Abstract

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.

Plant Growth, Yields and Fruit Quality of Processing Tomato (Solanum lycopersicon L.) as Affected by the Combination of Biodegradable Mulching and Digestate

“…Therefore, it's plausible to further lower the N amount supplied in the hosting farm by cutting the quote of N chemical fertilizers while supplying the most part of N through the solid digestate. As reported by different papers [6,7,35] it is possible a continuous use of digestate in vegetable crop successions. In particular, crops cultivated in spring-summer cycles can be fertilized only with digestate without the integration of chemical fertilizers.…”

The Potential of Digestate and the Liquid Fraction of Digestate as Chemical Fertiliser Substitutes under the RENURE Criteria

“…Digestate fertilisation in NVZ takes place from late winter through to the end of summer, starting at the earliest in February when plant N-demand is still low and mineralisation is slow because of the low soil temperatures. Thus, a better grasp of the interaction between TOC/TN and N min /TN for a specific soil-plant system might help in determining the optimal time of application (thereby increasing NUE and NFRV), where it might be argued that a combination of N fertiliser from both mineral (immediate availability) and organic forms (delayed availability) might be preferable for early spring crops; whereas for summer crops, the high mineralisation activity and ensuing higher NUE would mean that reliance on digestate with a higher organic load would cover the plant's demands [80] without jeopardising the environment. Another path worth exploring is the use of catch crops to effectively reduce nutrients' runoff and leaching.…”