Optimization of organic nitrogen fertilization in horticultural substrates for potted plant production (OptiFaz project)

O. Stapel, S. Bresch, M. Vale, P. Cannavo, R. Guénon, M. Benbrahim, M. Conseil
N-mineralisation and N-availability in an agricultural context are influenced by parameters such as soil properties (texture, pH, etc.), type of organic fertilizer (biochemical properties, C/N ratio, etc.) and environmental conditions (temperature, humidity). Prediction models on organic N-mineralization in soils and organic fertilizers already exist by using the normalized incubation day method. However, preliminary studies indicate that these prediction models are not transposable in soilless plant production systems using horticultural substrates. In these particular systems horticultural substrates often show important temperature and humidity fluctuations and the substrate's bio-physio-chemical properties can also be extremely variable due to different raw materials used in substrate formulations. The objective of the OptiFaz project is to develop models for predicting N-mineralization activity in horticultural substrates enriched with different types of organic fertilizers. This project equally aims at developing decision tools for growers and extension officers that may help determine mineralisation activity in the substrate by measuring chlorophyll and N-levels in plant tissue. Early detection of reduced N availability through simple plant measurements may assist growers in determining the need for additional organic fertilization. The different tools developed in this project may ultimately help to diminish crop accidents and losses related to nitrogen deficiency or excess due to poorly managed organic N fertilization in soilless plant production systems. Some first results are presented in this paper.
Stapel, O., Bresch, S., Vale, M., Cannavo, P., Guénon, R., Benbrahim, M. and Conseil, M. (2021). Optimization of organic nitrogen fertilization in horticultural substrates for potted plant production (OptiFaz project). Acta Hortic. 1305, 501-506
DOI: 10.17660/ActaHortic.2021.1305.66
organic N-fertilizer, peat, substrate, nitrogen mineralization, prediction and decision tools, organic horticulture, microbiome

Acta Horticulturae