Nitrogen is one the main elements needed by plants. It is an essential component of proteins, chlorophyll, vitamins, hormones and DNA. Because nitrogen is an integrant of enzymes, it has an essential role in all metabolic reactions in plants. One of the main differences in production between conventional and organic horticulture lies in the nitrogen supply. The main source of nitrogen in organic farming must come from (organic) manure or compost and the use of green manure. Additional fertilizers like liquid nitrogen fertilizers can be used when the compost and (green) manure does not supply sufficient nutrients. Nitrogen supply is a great challenge in organic horticulture, especially in areas with poor soils, like the ones in Almeria, where the so called enarenado technique is common. This technique consists of applying a high quality soil layer, organic matter and a sand mulch layer on top of the original poor soils. The enarenado technique is expensive and many growers are abandoning it to directly apply the organic matter and the sand mulch on top of the original soil, which is much less fertile, which poses a challenge to maintain productivity. Also excessive use of water and contamination of water with fertilizer residue is a present problem in Spanish horticulture. Therefore alternative solutions to provide nitrogen for plant growth need to be developed that can be applied in an organic farming environment. The availability of price-competitive organic fertilizers is scarce and yields obtained in organic greenhouses are still lower than under conventional greenhouses. These differences in yield are mainly attributed to limitations in availability of nutrients, since the greenhouse structures and the growing systems are the same under both types of management.
|Effective start/end date||1/01/21 → 31/12/21|