Linking root phenomics, nutrient acquisition and utilisation in amaranthus with thermochemical organic fertilizer from biowaste

Root phenomic interactions play a vital role in the rhizospheric environment. The objective was to study how root phenomic characteristics, soil nutrient acquisition by root and plant utilisation in amaranthus (Amaranthus tricolor L.) are linked to soil applied rapid thermochemical organic fertilizer produced from biowaste in a highly weathered Ultisol soil. Amaranthus was grown consecutively for three cycles with the thermochemical organic fertilizer and was compared with two conventional manures (farmyard manure, poultry manure) and three compost treatments (conventional compost, vermicompost and microbial compost). Root phenomic characteristics, plant biometrics, microbial proliferation and intensity, soil, root and shoot nutrient contents and yield components were analysed. Principal component analysis revealed superiority of the thermochemical organic fertilizer as compared to other organic manures. Thermochemical organic fertilizer addition enhanced soil resource dynamics influencing soil chemical parameters such as soil reaction, soluble salt content, oxidisable carbon fractions and absorbable essential nutrient ions, and biological parameters in terms of enhanced microbial intensity and activity. Linear regression models with a good fit were obtained for total root length with shoot nitrogen (R² = 0.9028), for root diameter with shoot phosphorus (R² = 0.9717) and for root biomass with shoot potassium (R² = 0.8544). Cyclic application of biowaste processed thermochemical organic fertilizer augmented the soil organic carbon pool, facilitated desirable root phenomic characteristics and microbial proliferation favouring foraging and root nutrient acquisition and utilisation resulting in an enhanced biomass production.