NUTRIENTS ALLOCATION AND THEIR USE EFFICIENCY IN PARTHENIUM-HYSTEROPHORUS LINN

Nitrogen, phosphorus and potassium concentration, their use efficiency, accumulation and allocation were studied in two cohorts of P. hysterophorus L. in field conditions for two years. Differences in concentrations of N, P and K between organs and cohorts were significant only during the first year. Relative concentrations of N and P in capitula were higher than other plant parts but the value for K was more in stem and leaf. Proportional allocation of N and P to capitula were higher than for K, but in terms of absolute values accumulation pattern was K > N > P. Reproductive allocation of mineral elements in the first cohort was higher than in the second cohort until 90 days after which it was almost equal in both of them or sometimes more in the second cohort but nutrient use efficiency (net primary production divided-by uptake) especially for P was always higher in the second cohort.