Articles
Improving nitrogen fertilization management in organic vegetable farming with decision support systems
Article number
1375_53
Pages
401 – 408
Language
English
Abstract
Decision support tools (DSS) are commonly discussed as a way to optimize nutrient management in open field vegetable farming.
Since DSSs are able to process large and diverse amounts of data, they can play a key role in fertilization management of organic vegetable farms through sustaining yields while avoiding negative environmental impacts from excess nutrient application.
The impact of four different fertilization management strategies (treatments) on the applied amount of nitrogen (N) fertilizer, yields and soil mineral N levels at harvest was assessed in on-farm trials at 11 different farms throughout Germany.
The trials were conducted with cabbage (Brassica spp.) and lettuce (Lactuca sativa L.) in three consecutive years (2019-2021). The farmers N fertilization (business-as-usual) was compared with the recommendations according to two DSSs: N-Expert and NDICEA. The maximum fertilization allowed according to the German legislation ordinance (DüV) was included as a fourth treatment.
The amount of applied N in the business-as-usual treatment did not differ significantly from the fertilization calculated with N-Expert and NDICEA for both cultivars (ANOVA with Scheffé-Post-Hoc Test, significant at p<0.05). The average N fertilization in all three treatments was significantly lower than the N fertilization according to DüV. The yields of cabbage were on average 17% lower in the treatment NDICEA than in the treatment DüV (all treatments: 219-265 dt ha‑1), while the reduction of the N fertilization did not result in lower yields for lettuce (330-344 dt ha‑1). The mean values of soil mineral N at harvest (0-30 cm) were highest in the treatment DüV (cabbage 29 kg ha‑1, lettuce 44 kg ha‑1). However, those differences were only significant in comparison with NDICEA for lettuce in 0-30 cm depth.
The existing fertilization management on the organic vegetable farms performed equally well as the DSSs N-Expert and NDICEA.
Since DSSs are able to process large and diverse amounts of data, they can play a key role in fertilization management of organic vegetable farms through sustaining yields while avoiding negative environmental impacts from excess nutrient application.
The impact of four different fertilization management strategies (treatments) on the applied amount of nitrogen (N) fertilizer, yields and soil mineral N levels at harvest was assessed in on-farm trials at 11 different farms throughout Germany.
The trials were conducted with cabbage (Brassica spp.) and lettuce (Lactuca sativa L.) in three consecutive years (2019-2021). The farmers N fertilization (business-as-usual) was compared with the recommendations according to two DSSs: N-Expert and NDICEA. The maximum fertilization allowed according to the German legislation ordinance (DüV) was included as a fourth treatment.
The amount of applied N in the business-as-usual treatment did not differ significantly from the fertilization calculated with N-Expert and NDICEA for both cultivars (ANOVA with Scheffé-Post-Hoc Test, significant at p<0.05). The average N fertilization in all three treatments was significantly lower than the N fertilization according to DüV. The yields of cabbage were on average 17% lower in the treatment NDICEA than in the treatment DüV (all treatments: 219-265 dt ha‑1), while the reduction of the N fertilization did not result in lower yields for lettuce (330-344 dt ha‑1). The mean values of soil mineral N at harvest (0-30 cm) were highest in the treatment DüV (cabbage 29 kg ha‑1, lettuce 44 kg ha‑1). However, those differences were only significant in comparison with NDICEA for lettuce in 0-30 cm depth.
The existing fertilization management on the organic vegetable farms performed equally well as the DSSs N-Expert and NDICEA.
Authors
S. Tietjen, K. Egenolf, R. Fischer, P. Schad, A. Sradnick
Keywords
organic fertilizer, on-farm, nitrogen, N-Expert, NDICEA, cabbage, lettuce
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