Effect of pH and Silicon in the Fertigation Solution on Vegetative Growth of Blueberry Plants in Organic Agriculture

Summary

This pot experiment investigated silicon supplementation (0–1.2 mM) and pH management (4.0–6.25) in fertigated blueberry production on two substrates. Silicon application to 1.2 mM in coir fibre significantly increased plant height (8%) and biomass (21–25% dry, fresh), though no benefit was observed in sand. Elevated pH (6.25) reduced growth in coir fibre, whilst citric acid proved an effective and organic-compatible acidification alternative to nitric acid.

Regional applicability

The study was conducted using hydroponic pot experiments with coir fibre and sand substrates rather than field conditions, and does not identify the geographic location of the trials. Findings on silicon supplementation and organic-compatible pH management may be relevant to UK protected horticulture and container-grown blueberry production, particularly in organic systems, though substrate composition and climate differences would require local validation.

Key measures

Plant height, shoot dry biomass, shoot fresh biomass, foliar surface area, stem dry weight, leaf dry weight; silicon doses (0.0, 0.3, 0.6, 1.2 mM); solution pH (4.00, 4.75, 5.50, 6.25); acidification source (nitric acid vs citric acid); substrate type (coir fibre vs sand)

Outcomes reported

The study measured vegetative growth parameters (plant height, shoot dry and fresh biomass, foliar surface area, and stem/leaf dry weight) in blueberry plants in response to silicon supplementation and nutrient solution pH under different substrate conditions. Silicon at 1.2 mM in coir fibre increased plant height by 8% and biomass by 21–25%, whilst pH effects were substrate-dependent, with alkaline conditions reducing growth in coir fibre but not sand.

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