Productivity, nutrient concentration, uptake and quality of Amaranthus (Amaranthus cruentus L.) as influenced by cutting heights and fertilizer type

摘要

Amaranthus cruentus L. is a leafy vegetable that is cultivated mainly for its leaves and grains. Due to high demand for this crop in Nigeria, the need to boost its productivity becomes necessary. Field and laboratory studies were conducted during in two successive cropping seasons at the experimental farm and laboratory unit of the Department of Crop Science, Faculty of Agriculture, University of Benin, Benin City. Three cutting heights C1: (10 cm), C2: (15 cm), C3: (20 cm) and a control C0: (no cutting) and four rates of fertilizer application F0: (Control), F1: (10 t ha-1 poultry manure), F2: (150 kg ha-1 NPK15:15:15) and F3 (75 t ha-1 NPK 15:15:15 + 5 t ha-1 poultry manure) constituted the treatments. The treatments were in three replicate laid out in a (4 × 4) factorial arrangement in a randomized complete block design. Data collected were plant height (cm), leaf area (cm2), stem diameter (cm) and number of branches. Fresh and dry herbage yield were taken at harvest. Growth, yield, and quality of Amarathus cruentus were significantly influenced by cutting heights and fertilizer application. In both years, number of branches (3.50 and 6.01) were lowest at C0 compared with other treatments. Herbage fresh and dry yield (49.10 t ha-1 and 18.20 t ha-1) were highest at C3 and was consistent in both years. Similarly, the concentration of K, Ca, and Mg in plant tissue and the uptake of nutrients (N, P, K, Ca, Mg, and Na) increase at C3 compared with other treatments. F3 significantly (p<0.05) produced highest dry herbage yield (13.08 t ha-1and 25.15 t ha-1) in both years. Crude protein, fibre and fat content of   the shoots were highest at cutting height of C3 and at F3 fertilizer rate. Therefore, for good yield and better quality of Amaranthus cruentus L, a combination of (75 t ha-1 NPK 15:15:15 + 5 t ha-1 poultry manure) at cutting height of C3: (20 cm above soil level) is recommended for Amaranthus cruentus L production in the study area.