Abstract
Tomato (Salanum lycopersicum L.) plug transplants were grown during winter in a region of Iraq under the jurisdiction of the Kurdistan Regional Government (KRG) using a closed plant production system and a nursery greenhouse equipped with a kerosene heater to extend the cultivation season. We developed a simplified closed transplant production system (SCTPS) equipped with an opaque container, multi-tier culture beds with artificial lights, and a domestic air conditioner. The objective of this study was to investigate the feasibility of seedling production during winter using the SCTPS and a nursery greenhouse in KRG. The facility costs of SCTPS and the greenhouse were 7,470 USD and 1,440 USD, respectively. Tomatoes were sown during November 2013. Tomato growth characteristics in SCTPS and the greenhouse were as follows: stem lengths, 6.2 and 4.0 cm; stem diameters, 2.1 and 1.4 mm; and numbers of unfolded leaves, 3.5 and 2.5 at 22 days after sowing, respectively. Compared with the greenhouse, SCTPS accelerated plant growth via optimal environmental control and shortened the seedling period. The electrical consumption of SCTPS was 0.15 kWh per plant, and its cost was 0.0036 USD in KRG during 2013. The fuel consumption of the kerosene heater in the greenhouse was 0.19 L per plant, and its cost was 0.22 USD. The average heating loads of SCTPS and the greenhouse were estimated to be 18.0 and 492.8 MJ･d-1, respectively, during January. SCTPS enabled the growth of seedlings with low energy consumption during winter in the KRG region.
