Effect of Nitrogen Sources, Sulphur and Boron Levels on Nutrient Uptake and Yield of Spring Sunflower

摘要

A field experiment was conducted during the spring season of 2005 and 2006 on spring sunflower (Helianthus annuus L.) at the research farm of Division of Agronomy, IARI, New Delhi. The objectives set out for the study aimed at studying the effect of N sources, S and B levels on dry matter accumulation, nutrient concentrations and their uptake at different growth stages of spring sunflower. Between two sources of N i.e. urea and calcium ammonium nitrate (CAN), CAN was found to be superior to urea in terms of nutrient concentrations and their uptake by sunflower. N concentration was recorded the maximum in leaf which declined from 25 DAS till harvest stage. At harvest stage, maximum concentration was recorded in seeds. S concentration in different parts of sunflower at different growth stages diluted with advancement in growth stages. The concentration was higher in stem and it became highest in seeds at harvest stage. Since S is more captured by seeds of sunflower, the uptake was also higher with S application @ 50 kg/ ha followed by B applied @ 1.5 kg/ha. B concentration was almost similar in leaf and stem initially and the ratio became wider at harvest stage. With the highest concentration in seeds, B application influenced the B distribution in plant parts. Initially more B uptake was recorded by leaves and later on stem became the net importer with the highest B uptake in seeds in both the years. Both the N sources had a positive effect on seed yield increase. Sulphur application had a significant effect on seed yield of spring sunflower during both years of study. The application of 50 kg S/ha increased the seed yield 11.6 and 2.0 and 15.3 and 5.5% over 0 and 25 kg S/ha, respectively, during 2005 and 2006. Application of B @ 1.50 kg/ha recorded 10.2 and 5.8 and 16.0 and 5.9% more seed yield over control and 0.75 kg B/ha, respectively, during 2005 and2006