Abstract:
Kenaf is a multi-purpose crop with numerous industrial uses. Its production is constrained by poor cultural and agronomic practices which reduce yield. Farmers rely on different types of Inorganic Fertilisers (IF), which may be harmful to the environment. Furthermore, inappropriate sowing dates and spacing results in low yield. Use of Organic Fertiliser (OF) with appropriate sowing date and plant spacing could improve yields of kenaf. However, there is dearth of information on the appropriate plant spacing, sowing date and rates of fertilisers application required for kenaf production. Therefore, effects of fertiliser types, plant spacing and sowing dates on growth and yield of kenaf were investigated in Ibadan, Nigeria.
Commercially produced OF (NPK 1.32-0.86-0.50) and IF (NPK 20-10-10) at the rate of 70, 100, 130, 160 kg N/ha were each mixed with 10 kg soil in pots. Pots were arranged in a completely randomised design with four replicates. Two kenaf (variety Ifeken 100) seeds were sown per pot and grown to maturity. Untreated pots served as control. Data were collected on Seed Yield-SY (t/ha). Best fertiliser rates; OF (160 kg N/ha), IF (100 kg N/ha) and their 50% combination (80-OF+50-IF), were evaluated on SY and Bast Fiber Yield-BFY (t/ha) of kenaf. Consequently, 80-OF+50-IF was applied to kenaf sown (2 plants/stand) at three plant spacing: 50×15, 50×20, 50×25 cm assessed for SY and BFY. Kenaf seeds were sown on three planting dates (30 days interval) from May to August at a spacing of 50×20 cm and application of 80-OF+50-IF. Data were collected on Plant Height-PH (cm), Stem Diameter-SD (cm), BFY and SY. All field trials were laid in randomised complete block design with three replicates. Data were analysed using descriptive statistics and ANOVA at α0.05.
In pot experiment, SY differed significantly among fertiliser types and rates. Among OF rates, SY ranged from 0.8±0.02 (control) to 2.0±0.02 (160 kg N/ha). Among IF rates, highest SY (1.5±0.02) was obtained under 100 kg N/ha, while control had the lowest (0.8±0.02). On the field, BFY and SY differed significantly among fertiliser types. The BFY and SY ranged from 0.7±0.4 (control) to 2.3±0.4 (80-OF+50-IF) and 1.2±0.1 (control) to 1.7±0.1 (80-OF+50-IF), respectively. Plant spacing differed significantly for BFY and SY. Highest BFY (0.9±0.03) and SY (0.5±0.01) were obtained at 50×20 cm and 50×25 cm spacing, respectively, while the lowest BFY (0.7±0.01) and SY (0.3±0.01) were obtained at 50×15 cm spacing. Planting dates differed significantly for PH, SD, BFY and SY. Plants sown in June had the highest (262.83±1.2) PH, while those sown in August had the lowest (173.79±1.2). The SD ranged from 1.19±0.02 (August) to 2.3±0.02 (May planting). The BFY was highest (0.9±0.01) in plants sown in June and lowest (0.32±0.01) in plants sown in August. The SY ranged from 1.2±0.01 (May) to 2.3±0.01 (July planting).
Combination of 80 kg N/ha organic fertiliser with 50 kg N/ha NPK 20-10-10 applied to kenaf planted at spacing of 50×20 cm in June and July improved its growth, bast fiber and seed yields in Ibadan.
