Yield and Root Quality of Two Sweetpotato (Ipomoea batatas [L.] Lam) Varieties as Influenced by Chicken Manure, Inorganic Fertilizer and Storage Methods

Abstract

Two field experiments were conducted at two seasons at the University of Education, Winneba, Mampong-Ashanti campus to investigate the responses of the yield and root quality of two varieties of sweetpotato (Apomuden and Okumkom) to chicken manure and inorganic fertilizers and storage methods. The experimental design used for the experiment was a 2 x 8 factorial arranged in randomized complete block design with four replicates in both seasons. The application of 15-15-15 kg/ha NPK+ 5t/ha CM  and 15-30-30 kg/ha NPK + 5t/ha CM to Apomuden produced thicker vine diameter and dry matter accumulation respectively during the major season while Okumkom grown on 30-30-30 kg/ha NPK gave longer vine length in the same season. However, the application of amended treatments to both varieties decreased root quality (root crack) during the major season and increased pest infested roots during the minor season. Okumkom grown on 15-15-15 kg/ha NPK+ 5t/ha CM plot produced higher forked roots at harvest in both seasons. Okumkom grown on 30-45-45 kg/ha NPK and 30-60-60 kg/ha NPK plots had increased root sugar and starch content at harvest during the major season. Both varieties, whether treated or untreated had decreased starch content at 12 weeks in storage than at harvest in both seasons. Pit storage showed the most effective storage method in terms of root starch and sugar content in both seasons followed by ash and grass storage methods.