Effects of phosphorus and zinc applications on the yields and yields components of sole early maturing maize (<i>Zea mays</i>) and bambaranut (<i>Vigna subterranean Thour.</i>) and in intercrop under southern guinea savannah ecology zone

Abstract

The effects of P and Zn applications on the yield components of these two crops was carried - out at the Teaching and Research Farm, University of Ilorin, in a 3 x 4 x 3 factorial and laid out in a split - split plot arrangement. The main plots consisted of 3 treatments (sole maize, sole bambaranut and maize/bambaranut intercrop), the sub plots were four levels of Zn (0, 0.5, 1.0 and 1.5kg Zn/ha) and the sub - sub plots were three levels of P (0, 35 and 70kgP/ha). Each treatment was replicated three times. Data were collected on the soil physico-chemical characteristics and plant physiological parameters. The data were statistically analyzed using analysis of variance (ANOVA) procedure. The results indicated that the soils of the experimental site were high in sand particles (788.7g/kg – 807.1g/kg); silt particles ranged from 49.5 - 106.3g/kg and clay particles ranged from 117.7 – 147.1g/kg; bulk density is 1.39g/cm³ and moderate in organic matter (2.18g/kg - 2.73g/kg). Exchangeable cations: K⁺ (0.30 - 0.49cmol/kg), Na⁺ (0.27 - 0.45cmol/kg), Ca²⁺ (2.37 - 2.40cmol/kg) and Mg²⁺ (1.52 - 2.00cmol/kg) and were slightly acidic (pH 6.1 - 6.2). Available P values were low (ranging from 4.36 - 5.32mg/kg) while available Zn were high with values ranging from 2.73 - 3.32mg/kg and the ECEC values ranged between 4.70 and 5.64mg/kg at 0 – 15cm and 15 – 30cm. There were significant responses of grain yield and all yield components of the two crops to the P applications and the treatments interactions. Grain yields and shelling percentages were however significantly lower in the sole crop than in the intercropped plants in the two crops. Generally, grain yield increased significantly (p≤0.05) and linearly with P application from 0 - 35kgP/ha at the application of 0 to 1.5kgZn/ha. There was no significant response to higher P application beyond 35kgP/ha, while there was no significant response of yields of both crops to Zinc at all levels of applied Zn. From these results, it can be inferred that application of P at 35kg/ha and Zn at 0.5kg/ha were best for optimum grain yield of both crops.

Keywords: Bambaranut, Maize, Phosphorus, Zinc, Yield