2018 Volume 17 Issue 4 Pages 423-429
Appropriate soil moisture is necessary for stable spinach production. We investigated the effect of water supply using Optimum Subsurface Irrigation System (OPSIS) with the aim of contributing to the development of a stable production technology for spinach. Our results confirmed that irrigation from multiple water supply lines allowed uniform spinach growth, irrespective of the plant position between water lines set 150 cm apart. The growth was promoted by underground irrigation through OPSIS, in comparison with above-ground water-spraying at the same soil pF value. The soil used for spinach cultivation in these experiments was an Andosol, for which the ideal soil pF value to start irrigation by OPSIS was 2.2. The amount of water for appropriate irrigation at this soil pF value was equivalent to 15 mm of rainfall on each occasion.
