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This report presents a study of crop coefficient (Kc) and yield response factors (Ky) for onion crop cultivated under deficit irrigation and different mulch covers in Samaru, Northern Nigeria. The field experiments were conducted at the irrigation fields of the Institute for Agricultural Research (IAR) irrigation field in 2008/2009 and 2009/2010 irrigation seasons using surface irrigation method. The experiments consisted of 16 treatments in each season. They comprised of four levels of water application depths (25, 50, 75, and 100% of weekly reference evapotranspiration (WRET)) and four levels of mulching (no-mulch, using rice straws, black and transparent polyethylene materials). Water applied per irrigation and soil moisture contents before and after irrigation was monitored throughout the seasons, while onion bulbs were harvested at the end of season and weighed. Average daily crop water use (crop consumptive use) were estimated from the soil moisture content using the soil moisture depletion method, while daily reference evapotranspiration (ETo) were computed from weather data using the FAO-Penman Montieth method. Crop coefficient values (Kc) were computed as the ratio of crop water use to ETo. The water stress coefficients (Ks) were computed by relating crop coefficient of the fully irrigated treatments to the deficit irrigated treatments. The yield response factor (Ky) were obtained by relating relative yield decreases to relative crop water use deficits. The study showed that crop water use of the onion crop decreased with increase in irrigation deficit. Applying water at 50% WRET reduced peak consumptive use of the onion crop by about 20%, while applying water at 25% WRET reduced crop water use by about 40%. Kc values of fully irrigated treatments ranged from 0.39 to 1.15, while Kc values of the deficit irrigated treatments varied from 0.24 to 1.13. Mulch materials did not significantly influence crop coefficient, but deficit irrigation did. Kc decreased with increase in water deficit with resultant water stress coefficients (Ks) ranging from 0.59 to 0.96. The relative yield decreases of the onion crop were proportionally greater with increase in evapotranspiration deficit for both mulched and no-mulch conditions. However, the proportional decrease in yield under the nomulch condition was much higher than the mulched condition. Among the mulch materials, the proportional decrease in yield in the polyethylene materials were over 10% lower than the rice straw mulch. The Ky of the onion crop under no-mulch condition was 1.15, while Ky values for the mulched treatments were 1.13, 1.00 and 1.05 for rice straw-, white polyethylene-, and black polyethylene-mulch, respectively. The crop coefficients and yield response factors developed in this study are reliable as they had similar trends in two seasons, and could be used in irrigation design and scheduling for onion in the study area.

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This study was conducted in Pampaida Millennium Village (PMV), Ikara Local Government Area of Kaduna State, Nigeria; during the 2009/2010 dry season to assess Tomato farmer’s irrigation water management practice using furrow irrigation. A total of 7 tomato farmers were selected out of 45 farmers for the assessment exercise. Soil moisture content was monitored throughout the growing season using gypsum blocks. The hydraulic performance of the farmer’s plots were assessed.  Similarly, the seasonal water requirement and irrigation schedule for the irrigated tomato were also determined. The results showed that the highest Application Efficiency, Distribution Uniformity and Adequacy of irrigation were obtained in plots T6 (92%), T3 (89%) and T7 (92 %) respectively. The least AE, DU and AI were obtained in plot T1 as 74%, 72% and 63% respectively. The yield obtained ranged from 11.6t/ha to 22.3t/ha. The least yield was obtained in plot T2; while the highest yield was obtained in plot T1. All the assessed farmers maintained a 4day irrigation interval throughout the growing season. The highest crop water use efficiency (CWUE) of 62.80 kg/ha-mm was obtained in plot T1, with a corresponding crop water use (CWU) of 355 mm/season. The least CWUE was obtained in plot T2 (41.6kg/ha-mm) with a corresponding CWU of 399 mm/season. Based on the results obtained it can be deduced that plot T1 gives best results among the assessed farmers’ plots in terms of crop water use efficiency and effectiveness of irrigation, which maximizes net farm profit.