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Shallot (Allium cepa var. ascolonicum) responses to plant nutrients and soil moisture in a sub-humit tropical climate

Woldetsadik, Kebede (2003). Shallot (Allium cepa var. ascolonicum) responses to plant nutrients and soil moisture in a sub-humit tropical climate. Diss. (sammanfattning/summary) Alnarp : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Agraria, 1401-6249 ; 367
ISBN 91-576-6195-2
[Doctoral thesis]

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Shallot requirements of nitrogen, phosphorus and potassium fertilizers were studied under rain-fed and irrigated conditions on heavy clay soils with low to medium organic matter contents in a sub-humid tropical climate of eastern Ethiopia. Influences of varying levels of irrigation water in combination with nitrogen fertilizer were assessed. Impacts of soil moisture stresses at different growth stages of the plant were evaluated in greenhouse and under field conditions. Different types of mulching materials were evaluated for their effect on the shallot crop and some soil characteristics. Parameters of plant growth, yield and bulb quality and storability were assessed in relation to applied treatments. The results showed the significance of soil moisture for shallot production in the sub-tropical climate. All mulching treatments improved shallot yields during the short season. During the main season, however, straw and clear plastic mulches favoured heavy weed infestation and reduced yields. Black plastic mulches increased yield up to three-fold without negative effects on the quality of bulbs. Soil moisture stresses at all growth stages severely affected shallot yield and quality. Frequent irrigation at 25% depletion of available moisture throughout the growing season was required to achieve high yields. However, frequent irrigation was also found to reduce the quality and storability of the bulbs. Nitrogen fertilization promoted vegetative growth, delayed bulb development and exposed plants to soil moisture stresses ahead of maturity and, thus, reduced yield of rain-fed shallots. When supplemental irrigation was provided, however, yield increases of about 10-15% from nitrogen fertilization in the range 75-150 kg ha -1 were achieved. The different nitrogen sources caused few and small differences in internal and external bulb quality. On the other hand, there were more storage losses in nitrogen-fertilized shallots. Phosphorus fertilization at rates of 25 or 50 kg ha -1 increased yield and bulb weight even when soil analysis did not show deficiency. On the other hand, potassium was not found to be a limiting nutrient in the clay soil used in this study. The potential for shallot yield improvements through irrigation and nitrogen fertilization needs consideration of better storage facilities. The advantages gained would otherwise be lost within few weeks after harvest as both conditions may increase storage losses and reduce bulb quality. Assessment of cultivars with better storability would also deserve further assessment.

Authors/Creators:Woldetsadik, Kebede
Title:Shallot (Allium cepa var. ascolonicum) responses to plant nutrients and soil moisture in a sub-humit tropical climate
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Agraria
Year of publishing :March 2003
Number of Pages:28
ALLI. Woldetsadik, K., Gertsson, U. & Ascard, J. Response of shallots to mulching and nitrogen fertilization. HortScience (in press). II. Woldetsadik, K., Gertsson, U. & Ascard, J. 2002. Season, and nitrogen source and rate affect development and yield of shallot. Journal of Vegetable Crop Production 8, 71-81. III. Woldetsadik, K., Gertsson, U. & Ascard, J. Response of shallots to nitrogen, phosphorus and potassium fertilizer rates. Submitted. IV. Woldetsadik, K., Gertsson, U. & Ascard, J. Yield, quality and storability of shallots as affected by irrigation and nitrogen fertilization. Submitted. V. Woldetsadik, K., Gertsson, U. & Ascard, J. Response of shallots to moisture stresses in Ethiopia. Submitted.
Place of Publication:Alnarp
Associated Programs and Other Stakeholders:Z - SLU - Library > Odla mera
ISBN for printed version:91-576-6195-2
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F01 Crop husbandry
F Plant production > F04 Fertilizing
Subjects:Not in use, please see Agris categories
Agrovoc terms:allium cepa, allium ascalonicum, vegetable crops, varieties, fertilizer application, nitrogen fertilizers, phosphate fertilizers, potash fertilizers, soil water content, irrigation, rainfed farming, mulching, crop yield, ethiopia, tropical zones
Keywords:Cultivar, Eastern Ethiopia, fertilizer, growth, irrigation, mulch, nitrogen, phosphorus, potassium, quality, rain-fed, shallots, stress, storage, yield.
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ID Code:203
Deposited By: Staff Epsilon
Deposited On:28 Mar 2003 00:00
Metadata Last Modified:20 Jun 2016 14:36

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