Effect of organic fertilizers on physical and chemical quality of sugar loaf pineapple ( Ananas comosus L ) grown in two ecological sites in Ghana

摘要

Pineapple has a large demand for plant nutrients and for this reason; fertilization is almost mandatory where the fruit is destined for sale. As consumer demand for organic food grows, organic production and certification is seen as a valuable alternative for smallholder farmers in developing countries. This study sought to investigate the effects of different organic fertilizers on the physical and chemical quality of pineapple ( Ananas comosus L.) cultivated in two different ecological zones in Ghana. Organic fertilizers treatments were POME (Palm oil meal effluent), Phos-K (PH), Yara (Y) and combination of Phos-K and POME (PH+P) and Yara + POME (Y+P) in the ratio of 1:1. Soil without fertilizer was control. A farmer field demonstration and an on-station experimental trial were conducted parallel at Nsakyi and at the Biotechnology and Nuclear Agriculture Research Institute (BNARI) research farm, respectively. The experiment was laid out in the Randomised Completely Block Randomized Design (RCBD) with five fertilizer treatments and four replications. Sugar loaf pineapples were harvested at 17 months upon maturity, washed, peeled, and juice extracted for analyzing vitamin C, Total Soluble Solids, pH, Titratable acidity, juice yield and colour. Fruits were weighed with Sartorius scale and percentage weight loss estimated over 15 days. The weight loss of pineapples treated with POME (25.56 ± 0.62 %) from BNARI farm was significantly (p<0.05) higher than all the other pineapple treaments. pH of all pineapple samples significantly (P<0.05) differed for all the different fertilizer treatments for both farms. Phos-K significantly (p<0.05) enhanced the vitamin C content of pineapples from both ecological sites Lightness (L*) and yellowness (b*) for juice of pineapple treated with Phos-K from BNARI farm was significantly (p<0.05) higher, than samples from Nsakyi farms indicating desirable visual appeal for sugar loaf pineapples. Organic fertilizers significantly (p<0.05) influenced the pH, vitamin C and juice yield of pineapples grown in the two different ecological zones. Irrespective of the ecological differences in Nsakyi and BNARI farm sites, the application of Phos-K to pineapple significantly (p<0.05) increased the juice yield which is a desirable quality of pineapple. Thus the application of Phos-K organic fertilizer, better improved the physical and chemical quality attributes of pineapple. However, there is the need to conduct further work on application rate and utilization efficiency of organic fertilizers that will produce maximum pineapple quality and yield. Keywords : Organic fertilizers, Juice, weight loss