Optimization of shading levels and fertilizer application on commercial production of vegetable fern (Diplazium esculentum)

Abstract

This aimed to assess the effect of shading and fertilization on safe vegetable fern production on a commercial basis. The experiment was carried out in a split-plot in a split-plot in randomized complete block design (RCBD) with 4 replications. There were 3 main plots of shading; 1) no shading, 2) 50% shading and 3) 80% shading, and 5 subplots of fertilization; 1) no fertilizer application (control), 2) chemical fertilizer (15-15-15_{30 kg/rai} + 46-0-0_{22.5 kg/rai}) at the rate of 52.5 kg/rai, 3) cow manure at the rate of 700 kg/rai, 4) cow manure at the rate of 1,400 kg/rai and 5) cow manure at the rate of 2,100 kg/rai. The results showed that the soil before and after treatments were very strongly acidic (pH 4.60-4.97). In addition, the decrease of soil organic matter was lower under the higher shading level than that under non-shading, whereas the available phosphorus and potassium increased with the rise of cow manure application. For the vegetable fern yield, it was found that the 50% shading combined with the application of cow manure at the rate of 1,400 kg/rai produced the highest amount throughout the 3 harvesting months (3-6 months after planting), which were 125.45, 177.10 and 152.43 kg/rai or average in approximately 152 kg/rai/month. Even considering the selling price throughout the year at 50 THB/kg, the investment can be returned within 1.5 years after planting, which it could be able to pay back 8.1 years faster than without shading and fertilization applications.