The rate of net assimilation and the rate of relative growth of amaranth (Amaranthus tricolor L.) varieties on urea fertilizer application

Nutrient availability affects plant growth and productivity measures, including net assimilation and relative growth rate. Nitrogen, such as amaranth, is vital for enhancing plant growth. Amaranth cultivation requires more nitrogen during its growth, which is met through fertilization. The most commonly used nitrogen fertilizer is urea. The goal of this research activity was to learn whether urea fertilizer had an impact on the relative growth rate and net assimilation rate of amaranth. This research was conducted in Sukosari village, Jumantono, Karanganyar, from July to August 2023. The experimental design employed a completely randomized approach, using two factors: the dose of urea fertilizer (0, 50, 100, 150, 200, 250, and 300 kg.ha-1) and the varieties of amaranth (green and red). At a significance level of 5%, the data analyzed variance (ANOVA) and the Duncan Multiple Range Test (DMRT). According to the conclusions, there was no interaction between the urea dose and the type of amaranth. At 300 kg.ha-1 of urea, the plant's height, leaf area, and leaf count all reached their highest points. At a urea dose of 250 kg ha-1, the rates of dry weight gain, net assimilation, and relative growth were greatest. The net assimilation rate is positively correlated to the relative growth rate but not to other growth parameters.