Two optimized biostimulants increase growth rate and yield of a maize variety

Declining water resources are a pressing climate change issue, as crop productivity and food security are highly dependent on irrigation. The results of recent field studies carried out by researchers in the AHIDAGRO project confirm that two optimized biostimulants (glycine betaine and L-pyroglutamic acid) increase the growth rate of a maize variety from Gran Canaria, its grain yield, and the calcium content of the flour ground from it. They are also associated with lower water consumption.

Declining water resources are a pressing climate change issue, as crop productivity and food security are highly dependent on irrigation. The results of recent field studies carried out by researchers in the AHIDAGRO project confirm that two optimised biostimulants (glycine betaine and L-pyroglutamic acid) increase the growth rate of a maize variety from Gran Canaria, its grain yield and the calcium content of the maize flour produced from it. They are also associated with lower water consumption.

The AHIDAGRO project addresses the challenges associated with water stress in crop plants by developing natural products and solutions that protect them during periods of water deficit. Funded by the European Union, AHIDAGRO is a collaborative project involving researchers from the IPNA-CSIC as lead research organisation, the University of La Laguna, the University of Madeira and the island Cabildo of Tenerife. It focuses on Macaronesia, a group of archipelagos in the North Atlantic that includes the Portuguese islands of the Azores and Madeira and the Spanish Canary Islands (sometimes Cape Verde is also included in the group). Across Macaronesia, the decline in water resources due to climate change is projected to reach up to 30% by 2050, with serious consequences for agricultural production and economic stability in the islands. Since the start of this project, the researchers involved have developed new methods to evaluate biostimulants and have tested new ones under field conditions. The results provide a practical knowledge resource for communities struggling with water scarcity around the world.

Laboratory studies in highly controlled environments can only take us part of the way. One of the main objectives of AHIDAGRO was to improve research into biostimulant applications on crop plants in the real world, in the field. To this end, the team conducted a study applying two biostimulants, glycine betaine and L-pyroglutamic acid, to a Gran Canaria maize variety (Zea mays L. c.v. Lechucilla). Seedlings were first sown in a growth chamber using a hydroponic system under deficit irrigation to optimize the biostimulant dosages. The plants were then transplanted to the field on Tenerife to test the optimal doses again under deficit irrigation (20% reduction in watering).

The results of the field trials confirmed that the optimized biostimulants increased plant growth rate, grain yield and calcium content of the maize flour produced from the grain. Its carbohydrate and protein contents were similar to those of the control plants, i.e. well-watered plants without applying biostimulants. Importantly, biostimulant treatments were also clearly associated with lower water consumption. Furthermore, as a root treatment, the glycine betaine and L-pyroglutamic acid could be applied by direct addition to the irrigation system, which helped to limit operating costs.

Between the two, glycine betaine proved to be much more economically viable, as the treatment cost 4.3 euros per hectare (compared to 171 euros/ha for L-pyroglutamic acid), resulting in a gain of 154.4 to 386.7 euros, depending on the irrigation medium (i.e. desalinated water versus groundwater). Overall, the low treatment cost, reduced water consumption and increased yields using glycine betaine offer a potential for economic and environmental sustainability.

The AHIDAGRO initiative addresses the challenges associated with water stress and climate change by developing natural products and solutions to protect crops during periods of water deficit. This collaboration project brings together experts from different research groups, public agencies and private companies to facilitate the exchange of knowledge and in-depth scientific and technical expertise. The main objective is to promote the adaptation of agricultural practices to the new climatic conditions, here using regional crops as models. Furthermore, although AHIDAGRO's work focuses on Macaronesia, the research team strives to ensure that its work is relevant to much wider areas. By focusing on methodological advances, their findings can be transferred to other agricultural systems and provide a resource for communities struggling with climate-change induced water scarcity around the world.

See the article in: Combating water stress in Macaronesia: Biostimulants and sustainable agriculture

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