Evaluation of STCR Based Targeted Yield Equations of Amaranthus (Amaranthus tricolor L.) in Southern Laterite Soils (AEU-8) of Kerala

A field experiment was carried out in the Instructional farm, Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, Thiruvananthapuram which comes under agro-ecological unit AEU-8 from the period March 2022 to June 2022 to test and validate the targeted yield equation for nutrient management developed by All India Coordinated research project on soil test based crop response studies (AICRP on STCR) 2014 for the cultivation of Amaranthus. The experiment was laid out in randomized block design with four replications and five treatment combinations viz., T1 as KAU organic POP, T2 as soil test-based KAU, T3, T4, T5 as STCR based targeted yield recommendation for a target yield of 20, 22.5 and 30 tonnes respectively. Nutrient management with the application of STCR based targeted yield recommendation for a target yield of 25 tonnes T5 showed a significant increase in plant height, stem girth, leaf length, petiole length, leaf width, number of branches plant-1, number of leaves plant-1 and root length at 30 and 60 DAS respectively. The treatment, T5 also improved the N, P and K content and their uptake by leaf, shoot and root respectively of Amaranthus and gave significantly better results for all parameters in comparison to other treatments. The equation of AICRP on STCR 2014 for the nutrient management for the cultivation of Amaranthus can be extended to the ultisols of AEU-8 of Thiruvananthapuram district of Kerala.