The Effect of Several Organic Amendments on the Growth and Yield of Edible Ginger to Evaluate the Transition toward Organic Farming Production
As many farmers transition toward organic farming, research-based information is required to determine the appropriate rates and timing for the application of available organic fertilizers. Four experiments were conducted over a 3-year period in Oahu, Hawaii, to evaluate the effect of five different organic amendments on the growth and yield of edible ginger. Fertilizer amendments, applied at a rate of 30–60 t·ha-1, included bone meal, a locally available commercial chicken manure-based compost, a commercial Bokashi compost, aged chicken manure, synthetic fertilizer (farmer's practice at 300 kg·ha-1 N), and a control. Each treatment plot consisted of a 10-m row with 15 plants per plot, and five replications per treatment. Ginger was planted in April of every year, and harvested from February to March of the following year. Data collected included soil fertility before initiation and after experiment completion, tissue nutrient levels, plant stands, plant height, and stem number, individual tops and root weight of 5–10 plants per treatment, as well as nematode counts before and after experiment completion. The data showed that similar or greater root weight yields and quality were obtained with the use of organic amendments compared to the use of synthetic fertilizer. Increased yields were obtained when organic amendment and fertilizer applications were split over the growing season. Data will be presented with regard to initial plant stands, tissue levels, and yield trends in response to the several amendments used in these experiments, and management considerations for farmers will be discussed.