Impact of poultry manure and harvest season on juice quality of yellow passion fruit (Passiflora edulisvar.flavicarpaDeg.) in the sub-humid zone of Nigeria

Abstract

Introduction . The production of high quality fruit juice involves several cultural inputs. Among other factors, fruit quality attributes are influenced by the cultivar, the climate, the harvesting time and soil fertility. Particularly, the soil fertility has a significant effect on the nutritional characteristics of the juice. Good practice as regards fertilization consists of applying rates adapted to plant optimum growth, yield and fruit quality. Materials and methods . Effects of four poultry manure rates [(0, 5, 10 and 15) t·ha–1 ] on the juice quality of passion fruits (Passiflora edulis var. flavicarpa ) were evaluated for two cropping years (2005 and 2006). The seedlings of passion fruit vine were field-established in a randomized complete block design, and the manure treatments were replicated four times. Juice quality assessment was performed on fruits picked in December 2005, coinciding with the dry season and low soil moisture recharge, and August 2006, during the wet season and high soil moisture recharge. Results . The results obtained indicated a significant poultry manure effect on all the juice quality parameters studied; the quality of the juice increased gradually as the manure rate increased. Similarly, the season of fruit-picking had a significant effect on the juice quality. As expected, vines that received no manure produced fruits with the poorest juice quality, suggesting unfavorable nutritive conditions within the vines. The concentrations of anti-nutrient factors (tannin, hydrogen cyanide, phytate and calcium oxalate) were low in ripe yellow passion fruits, and insignificant regarding health hazards for consumers of yellow passion fruit. Conclusion . The results obtained showed that the manure rate and the harvest period affected the quality of passion fruit juice. Application of 15 t·ha–1 poultry manure generally gave the best juice quality; similarly, fruits harvested in the first cropping season had better juice quality.