Production of High Soluble Solids Tomato Fruits on the Long-term Cultivation by Control of Nutrient Solution Supply Based on Solar Radiation in Hydroponics Using Substrate Made with Mixing Coconut Husk and Bark Compost

Summary

This field trial examined long-term hydroponic tomato cultivation using an organic substrate of coconut husk and bark compost, with nutrient solution regulated by solar radiation accumulation. The study demonstrated that organic substrates showed superior water retention and drainage compared to rockwool, and identified an optimal nutrient supply rate (1.93 MJ·m⁻² per 100 ml·plant⁻¹) that maximised the yield of high-soluble-solids fruit (Brix ≥8%) whilst maintaining acceptable total marketable yield.

Regional applicability

This research was conducted in Japan and addresses glasshouse hydroponic tomato production using solar radiation-proportional irrigation control. The findings on substrate properties and nutrient scheduling may be transferable to United Kingdom horticultural systems, particularly in protected cropping, though UK light conditions and growing seasons differ significantly from Japan; adoption would require calibration to local solar radiation patterns and growing practices.

Key measures

Water retention characteristics of substrate, leaf area variation, accumulated solar radiation, evapotranspiration, marketable fruit yield (kg), average Brix (°), high-quality fruit yield (Brix ≥8%)

Outcomes reported

The study evaluated the effects of solar radiation-proportional nutrient solution supply on yield and fruit quality (sugar content) in long-term tomato cultivation using organic substrate composed of coconut husk and bark compost. High-soluble-solids fruit yield was maximised at an intermediate nutrient supply level (1.93 MJ·m⁻²), balancing total marketable yield against sugar concentration.

Topic tags