Drip irrigation scheduling for optimizing productivity of water use and yield of dry season pepper (<i>Capsicum annuum</i> L) in an inland valley swamp in a humid zone of Nigeria

Abstract

The effects of drip irrigation schedules (weekly and fortnight intervals) on water use, yield and water productivity of dry season pepper grown in inland valley swamp was investigated between December 2009 and May, 2010. The first planting (December, 2009) adequacy of soil moisture from planting to date of first flowering was assumed, thereafter irrigation was imposed during reproductive growth. In the second sowing (Janaury, 2010), pepper seedlings were drip-irrigated weekly and fortnightly from transplanting to fruit harvest. In both experiments, irrigation was imposed using low-head (gravity) drip system weekly and fortnightly and 1.38 litres of water per plant at each irrigation while soil moisture storage ranged from 100 to 50 % of plant available water. Higher root biomass and densities at soil depths were obtained for fortnight irrigation over weekly. Within the crop root zone, and across irrigations, soil moisture contents ranged between 14.7 and 11.8% for the respective surface (0 – 20cm) and lower (30-45 and 45-60 cm) soil depths. Soil moisture tension were - 7 to -10 bar and -10 to -14 bar for the respective seedling establishment and reproductive growth phases. Total fruit yield and water productivity were higher (8.8 and 1.85 kg/ha/mm) in December over January (8.5 t ha -1 and 1.25 kg/ha/mm) sowing. In addition, over weekly (9 t ha -1 ) irrigation, fruit yield obtained (8.1 t ha -1 ) under fortnight irrigation translated to 24 % water savings.