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Combinations of organic and inorganic fertilizers for vine, carotene and root yields of orange-fleshed sweetpotato at Umudike, southeastern Nigeria


F Akpaninyang
DA Okpara
JC Njoku
P Ogbologwung
B Okpara
AE Akpan
L Jan

Abstract

Field experiment was conducted during 2013 and 2014 cropping season at Umudike, southeastern Nigeria, to  evaluate the effect of fertilizer combinations (poultry manure, NPK (15:15:15) and agrolyser) on two varieties  of orange-fleshed sweetpotato (Ipomoea batatas). The experiment was a split-plot laid out in randomized  complete block design (RCBD) with three replications. Combined application of 2.5 t/ha poultry manure + 200  kg NPK produced significantly higher leaf area index of 3.3, shoot biomass of 31.9 t/ha and multiplication ratio  of 1:48than the control or application of NPK or agrolyser alone. Application of 2.5 t/ha poultry manure + 200 kg  NPK also produced significantly higher average storage root yield of 29.1 t/ha than no fertilizer or agrolyser application, and also gave higher carotenoid level than application of NPK or the control. Umuspo 1 suppressed weeds more and significantly produced 598% higher shoot biomass and 125% higher average storage root yield than Umuspo 3. Umuspo 3 variety however, had a carotenoid level of 2268.1mg/g, which was higher than that of Umuspo 1 by 1860%. The highest net monetary returns from the cultivars accrued from a combined  application of 2.5t/ha poultry manure and 200 kg NPK while the lowest return was from where no manure was applied or where agrolyser was applied alone.


Keywords: Carotene, fertilizer combinations, orange-fleshed, Ipomoea batatas, yields


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print ISSN: 0300-368X