Title : NPK fertilizer requirements for Jatropha zeyheri indigenous tea under greenhouse conditions
Abstract:
Jatropha zeyheri is an indigenous crop to South Africa, which contains tea brewing and medicinal properties commonly utilized by local communities in rural areas of South Africa. Indigenous teas have been receiving much attention due to their health benefits. Domestication and commercialization of indigenous herbal teas have gained popularity in recent years. However, domestication of J. zeyheri will require optimum NPK fertiliser mixture to improve yield and quality. Therefore, the study was intended to determine whether different fertiliser application rates would optimize yield parameters of J. zeyheri tea under microplot conditions. At two-leaf stage, J. zeyheri seedlings were transplanted into 25 cm diameter plastic pots. Each pot was filled with heated-pasteurised sandy soil and Hygromix at 3:1 (v/v) ratio and placed in a spacing of 0.30 m × 0.30 m inter-and intra-row spacing. Treatments, viz., 0, 2, 4, 8, 16 and 32 g of NPK 2:3:2 (22) fertiliser mixtures were arranged in a randomized complete block design, with five replications. Treatments were initiated a week after transplanting, and 130 days after that, treatments had highly significant effects on leaf width, contributing 66% in TTV, whereas significant effects were reported on vine length, stem diameter, leaf length and dry root mass contributing 61, 67, 68 and 49% in TTV, respectively. NPK fertilizer rates did not affect chlorophyll content, NDVI, dry shoot mass, number of leaves and leaf area index. Jatropha zeyheri yield variables when exposed to increasing fertilizer rates displayed positive quadratic relations. Use of fertilizers had setbacks when applied inappropriately leading to inconsistent results. However, determining optimum fertilizer requirement for J. zeyheri was a strategical solution for inappropriate application. Jatropha zeyheri fertilizer requirements were optimized at 3.30 g fertilizer/plant, which shows that J. zeyheri requires a minimum amount of NPK fertilizer to stimulate growth.
Keywords: botanicals, fertilizer, Jatropha zeyheri, primary nutrients, tea yield