Effects of NPK fertilizer on growth and yield of Nigerian turmeric (Curcuma longa linn.) germplasm in coastal rainforest ecology of Nigeria

The study investigated the responses of 10 Turmeric Nigerian Curcuma Longa (NCL) Germplasm, to NPK nutrient rates and its effect on some soil properties. The experiment laid out, was a 3 x 10 factorial in RCBD, to evaluate the growth and yield performance on coastal rainforest soil in Nigeria. The following data were collected: soil physico-chemical properties, tiller count, leaf area (cm2), plant height (cm), plant biomass (mtons ha-1), economic yield (mtons ha-1) and harvest index. Also, linear correlation matrix and traits variability of the accessions were characterized. Data were subjected to ANOVA, as outlined for factorial in RCBD. Treatment means were separated using Fisher’s least significant differences (p < 0.05). The soil is acidic (3.60 - 5.20), low total Nitrogen (1.10 - 1.12 g kg-1) and exchangeable bases with Potassium (0.02 – 0.15 cmol kg-1 soil). Nutrient rates at 150 kg N, 50 g P2O5, and 50 kg K2O (500 kg ha-1NPK), significantly (p<0.01) improved tiller count clump-1 (4.85), leaf area (187.70 cm2) and plant height (54.97 cm), better than the control 2.65, 156.60 cm2 and 45.93 cm, but similar with the nutrient rate of 200 kg N, 100 kg P2O5, and 100 kg K2O (1000 kg ha-1), which recorded 4.19, 183.20 cm2 and 54.54 cm, respectively. The correlative coefficient values to each trait, was positively significant (p < 0.01). Hence, tiller number clump-1, broader leaf area and plant height are complementary and serve as good growth indices for yield determination. The Economic yield differed significantly (p < 0.05) with nutrient rate at 150 kg N, 50 kg P2O5, and 50 kg K2O, with accessions NCL 37 - 70.85 mtons ha-1 and NCL 39 - 45.90 mtons ha-1, better than the control (36.31 and 34.38 mtons ha-1), but similar with nutrient rate at 200 kg N, 100 kg P2O5, and 100 kg K2O of NPK 1000 kg ha-1, which gave 80.36 and 58.10 mtons ha-1. Threfore, Nutrient rate of NPK 20:10:10 at 500 kg ha-1, was cost effective. Turmeric accessions NCL 37 and 39 that were characterized are selected for farmers in the ecological zone