Structured water uses in improving rhizosphere microbiota and growth of Cleistocactus strausii

Research objective: The paper presents the results of research aiming plant growth and to stimulate microbial communities in rhizosphere of Cleistocactus strausii which was watered with structured water under controlled conditions.

Materials and Methods: The experiments, which began in January 2023, were conducted in the CREA-OF greenhouses in Pescia (PT), Tuscany, Italy (43°54′N 10°41′E) on Cleistocactus strausii. The plants were placed in ø12 cm pots; 30 plants per thesis, divided into 3 replicates of 10 plants each. The experimental groups were: i) group without structured water, irrigated with water and previously fertilised substrate; ii) group with structured water, previously fertilised substrate. On 20 January 2024, plant height, stem circumference, vegetative weight, root weight, root lenght, number of new suckers, microbial count in the plants (evaluation of the type of bacteria and fungi in the substrate) were measured.

Results and Discussion: The experiment showed that the use of structured water can improve the vegetative and root growth of Cleistocactus strausii plants grown in pots. The treatment also resulted in an increase in plant height, stem circumference, root hair length and number of new suckers. The trial also highlighted how the use of structured water in plant growing media can increase bacterial and fungal biodiversity in terms of number and taxonomic diversity. In fact, the substrates of the treated plants showed the presence of 5 different bacterial and fungal taxa compared to the control. The presence of fewer plants affected by biotic phytopathologies is evident in the treatment with structured water.

Conclusions: Specifically, structured water has been shown to promote the growth of Cleistocactus strausii, according to experimental results. Plant height, vegetative and root biomass were significantly increased. Additionally, the number of useful microorganisms found on the substrate of theses treated with structured water increased, which likely supported plant growth improvement. Plants can also be affected by microorganisms in their substrates if they are exposed to biotic or abiotic stress. These aspects consequently become very interesting for the grower who can reduce the use of water and fertilisers and increase the quality of the plants by using alternative techniques.