Crop coefficients and yield response factors for onion (Allium Cepa. L) under deficit irrigation and mulch practices in Samaru, Nigeria

Abstract

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.

Developed Water Stress and Crop Coefficients of Dripped-Onion Crop under Arid Conditions of Egypt

“…In addition, from data analyses it could be noticed that, the highest values of CWU reduced under establishment, vegetative growth, bulb fermentation and bulb enlargement and maturity stages respectively. These observations are in agreement with Igbadun and Oiganji [1] and Fereres and David [13].…”

“…With this point of view, data analysis indicated that the highest k c values were obtained under I 100 followed by I 70 and I 40 respectively. These data are in agreement with Igbadun and Oiganji [1].…”

“…Igbadun and Oiganji stated that the kc values of fully irrigatedonion treatments had ranged from 0.36 to 1.15, while those values of the deficit irrigated treatments varied from 0.24 to 1.13 under Samaro district, Nigeria [1]. Meanwhile, Susan et al [2] speculated that variations of the crop water stress index (CWSI) have been used to characterize plant water stress and schedule irrigations.…”

<b>Organic cultivation of onion under castor cake fertilization and irrigation depths

“…Igbadun and Oiganji (2012), Ramalan, Nega, and Oyebode (2010) and Ribeiro et al (2016) observed that irrigation depths had similar effects on the yield of onion bulbs. The reduction in irrigation depth of 36% (321 to 204 mm) in 2014 and of 37% (444 to 278 mm) in 2015 resulted in losses of 29, 30, 33, and 11% and 38, 38, 34, and 17% in TY, MBFW, MBDW and MBD, respectively, in each year.…”

Avaliação De Métodos De Estimativas Da Evapotranspiração De Referência Em Um Cultivo De Cebola Irrigada

“…A cebola (Allium cepa L.) pertencente à família Alliaceae é a segunda hortaliça mais valiosa do mundo, ficando atrás apenas do tomate (El Balla et al, 2013); entre os vegetais bulbosos, é uma das principais culturas, tendo uma grande importância econômica no mundo (Igbadun & Oiganji, 2012). Entretanto, para bons rendimentos, a cultura requer irrigação frequente.…”