Fertilizer Rate on Growth, Yield, and Nutrient Concentration of Leafy Vegetables

Abstract

ABSTRACTIn the Mount Cameroon region, vegetables are traditionally planted without use of fertilizers. Increased demand and continuous cultivation on the same land over a long period requires that crops require addition of fertilizer, but most farmers apply fertilizers indiscriminately. As a result, yields of Amaranthus cruentus L. and Vernonia hymenolepis A. Rich have been reduced. It is necessary to investigate the effects of type and amount of fertilizers on growth, yield, and nutrient concentrations in these vegetables. Nine fertilizer treatments and a no fertilizer treatment (a common practice) were used. Data were collected biweekly for plant height, number of leaves, relative leaf area, collar diameter, and petiole length. For V. hymenolepis and A. cruentus, respectively, tallest plants (56.67 and 84 cm), most leaves (38 and 84), highest relative leaf area (137.67 and 177.23 cm2), widest collars (19.10 and 33.17 mm), and longest petioles (5.61 and 13.58 cm) were for those treated with a combination of poultry manure at 30 Mt·ha−1 and NPK at 275 kg·ha−1. Leaf N, P, Ca, and K and Fe, Cu, Mn, and Zn contents increased due to application of fertilizers compared to the control. Optimum yield (17.05 and 10 Mt·ha−1) in A. cruentus and V. hymenolepis, respectively, was with application of poultry manure at 30 Mt·ha−1 + 20N–10P–10K at 275 kg·ha−1. Combining specific amounts of synthetic fertilizer and manures appears to be useful for improved yields at a potentially lower cost.