ABSTRACT
The aim of this study was to evaluate the effect of various types of organic fertilizers on the growth of Amaranthus caudatus. The study consisted of ten (10) treatments, including control (no fertilizer) and 1%, 2%, and 3% treatments with poultry manure, cow dung manure and domestic compost separately with Amaranthus caudatus in a factorial arrangement fitted into a randomized complete block design (RCBD) and replicated three times. Data for growth parameters (height, number of leaves, leaf length, leaf width, leaf area and number of branches) were collected from 1 week after transplanting (1WAT) to 6 weeks after transplanting (6WAT). At 6 WAT, 1% poultry manure treatment recorded the highest value for all the growth parameters except for leaf width of Amaranthus caudatus, where 3% cow dung fertilizer was highest. At 6 WAT, 1%, 2%, 3% poultry manure; 1%, 2%, 3% cow dung manure and 1%, 2%, 3% domestic compost recorded leaf area values of 111.66±24.11cm3, 74.33±3.17cm3, 64.66±22.34cm3, 73.33±5.84cm3, 75.00±9.71cm3, 85.00±10.50cm3, 25.33±2.66cm3, 31.33±1.20cm3, and 34.66±3.71cm3 respectively compared to the control which elicited leaf area of 5.33±0.33 cm3. The treatments (1% poultry manure, 3% cow dung and 3% compost) showed enhancing effect on proximate composition (ash, lipid, crude protein, crude fibre, available carbohydrate and dry matter) compared to control. Amaranthus caudatus grown in 1% poultry manure had the highest ash, fibre, protein and dry matter at 4.29±0.24%, 30.13±0.52%, 6.54±0.19% and 71.84±0.23% respectively and were significantly different (p<0.05) from other treatments. Lipid was highest in 1% poultry manure treatment but was not significantly different from 3% cow dung manure treatment. Amaranthus caudatus grown in 3% cow dung had the highest moisture content but was not significantly (p<0.05) different from plant derived from 3% compost manure and control treatment. Plants derived from 3% compost elicited the highest available carbohydrate at 32.09±0.54 but was not significantly (p<0.05) different from control. Amaranthus caudatus grown in 1% poultry manure treatment elicited the highest levels of Ca, Mg, K, Na, P, Zn, Feat 0.87±0.03mg/g, 4.78±0.017mg/g, 42.54±0.65mg/g, 0.73±0.011mg/g, 0.57±0.006mg/g, 0.07±0.002mg/g and 0.36±0.007mg/g respectively and showed significant (p<0.05) difference among the treatments. Total lead in Amaranthus caudatus plants derived from pots treated with the 1% poultry manure were highest among the treatments for lead with value of 1.66±0.14mg/kg and were significantly (p<0.05) different from other treatments while cadmium was not detected in any of the treatments. The results of this study have shown that poultry manure had higher growth performance and available nutrients at 1% on Amaranth when compared with cow dung and household compost but also recorded the highest level of lead. The application of poultry manures at 1% for potted sowing is therefore recommended for use to obtain higher yields of Amaranth.
