Comparative study on the effect of fertilizers on agronomic and biochemical characters in Amaranthus sp.
The genus Amaranthus, belonging to the family Amaranthaceae, is a widely cultivated taxonomic group of about 70 species. The current study is aimed at understanding the incidence of organic and inorganic fertilizers on the various growth parameters of the plant, soil used for planting and plant biochemical composition in two commonly available cultivated species of Amaranthus in Kerala - A. caudatus and A. tricolor. Both the species were grown separately in block design and were treated with organic and inorganic fertilizers. Growth parameters were recorded till the attainment of reproductive maturity. The plants were harvested on the completion of their vegetative phase. The samples treated with organic fertilizers, inorganic fertilizers and control were then subjected to biochemical analysis. Soil used for cultivation was sampled and tested for nutrient status before planting and after harvest. Plants treated with inorganic fertilizers produced the maximum response in growth parameters. The variations in stem height and number of leaves were seen to be statistically significant, based on the chi-square test values. The contents of dietary constituents viz. carbohydrates, reducing sugars, starch, proteins, amino acid, and vitamin C and the phytochemical constituents viz. phenolics, flavonoids and tannins were more in plants treated with organic fertilizers. Analysis on soil pH, total soil carbon, total soil phosphorus and total soil nitrogen prior to and after treatment showed variations. The soil was found to have retained the fertility after treatment. The experimental results have showed that organic fertilizers produced higher nutritional values and soil nutrient retention during the cultivation of A. caudatus and A. tricolor when compared with inorganic fertilizer. Inorganic fertilizers exhibited superior characters in market-friendly characters (Growth parameters) only. The results of this study therefore, encourage the use of organic fertilizer in the cultivation of Amaranthus spp. for better nutritional quality.