Yield and forage properties of Jerusalem artichoke (Helianthus tuberosus) in different harvest intervals

The aim of this study was to determine the effect of harvest interval (re-growth) on quantitative and qualitative traits of Jerusalem artichoke as a promising forage plant. For this purpose, an experiment was conducted at a Research farm of Animal Science Research Institute, Karaj, Iran in 2015 and 2016. The experiment was based on randomized complete block design with three replications and two observations. The treatments consisted of different times of harvesting forage intervals in each two, three and four months in the first year and each one, two, three, and four months after emergence or regrowth in the second year. Replant was not done in the second year. The highest dry weight of leaf, stem and total forage was obtained with harvest interval in each two months. The highest crop growth rate, relative growth rate and biomass duration and the highest growth rate, relative growth rate and biomass duration were observed in cut intervals of three, four and two months, respectively. In the second year, the highest amount of crude protein of total forage were observed in the cut intervals of one month. The highest amount of ADF of total forage was observed for cut intervals of four months. Generally, the best time for harvesting of forage can be taken each two months due to high yield forage (2056 g/m2), leaf to stem ratio of 0.53, crude protein of 12.50 percent, water-soluble carbohydrates of 3.89 percent, ADF of 32.98 percent and NDF of 46.05 percent of the Jerusalem artichoke.