Fruit Yield of Tomato Cultivated on Media with Bicarbonate and Nitrate/Ammonium as the Nitrogen Source

Summary

This hydroponic glasshouse study examined how the form of nitrogen nutrition and bicarbonate supplementation influence tomato fruit yield and composition. Plants supplied with nitrate alone produced approximately 25% higher fresh fruit yield than those receiving ammonium alone, whilst a 4:1 nitrate-to-ammonium ratio increased yield by 20% compared with nitrate-only controls. Bicarbonate enrichment further enhanced fruit bearing, with combined bicarbonate and nitrate treatment yielding approximately 28% more fruit than controls, alongside substantial increases in fruit sugar concentration (up to 10% improvement in ammonium-fed plants).

Regional applicability

The study was conducted under controlled hydroponic glasshouse conditions with no declared geographic origin; transferability to United Kingdom field conditions or commercial horticulture would require validation, particularly regarding the utility of bicarbonate amendment in natural growing media and the relevance of nutrient ratios to soil-based or alternative growing systems employed in UK horticultural practice.

Key measures

Fruit fresh matter yield (from four clusters), reducing sugar concentration, carboxylate concentration (malate and citrate), nitrogen source ratios (NO3−/NH4+ at 4:1, 1:1, and other proportions), bicarbonate concentration (5 mmol)

Outcomes reported

The study measured fruit fresh matter yield and chemical composition (reducing sugars, carboxylates) of hydroponically grown tomato plants in response to different nitrogen sources (nitrate vs ammonium) and bicarbonate supplementation. Key findings included differential yield responses and changes in fruit sugar accumulation depending on nitrogen form and bicarbonate presence.

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