Effects of planting density on growth and yield of hydroponically-grown pak-choi (Brassica campestris ssp. chinensis).

摘要

The growth and yield of hydroponically-grown pak-choi (Brassica campestris subsp. chinensis) were investigated under different planting densities (27, 33, 44, 67 and 133 plants/m2). The number of leaves and top fresh weight per plant were decreased with increasing planting density, while yields per area were increased reaching a maximum value at 133 plants/m2. Maximum crop growth rate, light use efficiency yield and yield index, which are closely related with planting density, were the highest at 67 plants/m2. The yield index was 23-31% higher at 67 plants/m2 than that at 133 plants/m2. The marketable rate, which was 100% between 27 and 44 plants/m2, was sharply decreased with increasing planting density and then became the lowest at 133 plants/m2 due to the poor light environment, while the marketable yields per area were the highest at 67 plants/m2. From a practical point of view, the marketable yield per area was an appropriate factor to evaluate the planting density in hydroponics, a 67 plants/m2 (15x10 cm) was considered as an optimum planting density for hydroponically-grown pak-choi..