Yield of greenhouse-grown tomato in substrates containing coir and parboiled rice or burnt rice hulls

ABSTRACT

Substrate components produced in the sub-tropics or tropics were combined in various proportions as substrates for the greenhouse production of ‘Big Beef’ tomato. Coir was mixed with parboiled rice hulls (PBH) or burnt rice hulls (BRH) at 0, 25, 50, 75, or 100% volume. Fruit fresh weights at equal proportions of BRH or PBH in coir were similar, with the greatest fruit yields achieved with 50 to 100% coir (0 to 50% PBH or BRH). Compared to 100% coir, PBH in coir decreased substrate container capacity and increased air porosity, while BRH in coir increased container capacity and decreased the air porosity. Pre-plant fertilisation of the PBH + coir substrates (superphosphate, gypsum, trace elements, calcium nitrate, and surfactant) increased fruit yield significantly. Substrates containing 50 to 100% coir with BRH or PBH yielded greater fruit fresh weights than was achieved in in 70% BRH + 30% gravel (a typical substrate used in the Dominican Republic), and reusing the 70% BRH + 30% gravel led to a 36% increase in fruit fresh weight. Fruit fresh weights in 100% coir or 75% coir plus 25% PBH or BRH were similar to those achieved in a commercial peat-lite. Herein we report on substrates made from tropical components that perform similarly to a peat-based substrate in the production of greenhouse-grown tomatoes.

KEYWORDS:

• Burnt rice hulls
• carbonized rice hulls
• coir
• parboiled rice hulls
• peat-lite
• soilless growth medium

Acknowledgements

We acknowledge Quintin Richard of Agrilectric Research Co., Lake Charles, LA, USA, for providing burnt rice hulls. We thank the US Agency for International Development, their Feed the Future program, and Farmer to Farmer for supporting our travel and field research in Jamaica and the Dominican Republic over the past 10 years, which led to the initiation of this research.

Disclosure statement

No potential conflict of interest was reported by the authors.