The Effects of Liquid-coating Mulch Spray on Growth, Yield and Undersoil Temperature in Komatsuna Greens (Brassica rapa L.)

Abstract

This experiment was intended to examine the effects of a black liquid-coating mulch on the growth and yield of Komatsuna greens. Four treatments (1, 0.5, 0.25 L·m⁻²) of spray amount were tested in combination with seeding date (Sep. 21^st, Oct. 5^th, Oct. 20^th in an open field and the Jan. 22^nd in a plastic film house). As a result, we found this liquid-coating mulch increased yields of Komatsuna greens, unrelated to the spray amount. Generally, the daily highest soil temperature (−5 cm) under the mulching exceeded the control in every treatment however the daily lowest temperature were less than control except in the case of seeding at Sep. 21^st. These phenomena were remarkable in the early stage of growing and the differences in temperature between the control and mulch treatments were reduced during the growth. There was no significant difference in the hourly-integrated temperature during the first 10 days between the 4 treatments on same seeding date. These findings suggest that the expansion of the daily soil temperature range contributed the increased yields of Komatsuna greens.