Effect of different levels of nitrogen fertilizer on silage quality of Artichoke (Cynara scolymus L.)

To study the effect of different levels of nitrogen fertilizer on silage quality of artichoke (Cynara scolymus L.) an experiment was conducted using a randomized complete block design with three replications in Isfahan, Iran in 2014. The N application rates were 0, 100, 150 and 200 kg ha-1. Plants were harvested at vegetative rosette stage and submitted to ensiling in experimental silos for 75 days. The results showed that different levels of N fertilizer significantly affected silage quality. Crude protein (CP), ash, organic matter digestibility (OMD), metabolizable energy (ME) and net energy for lactation (NEL) increased by the increment of N fertilizer application while neutral detergent fiber (NDF) and crude fat (CF) reduced. The highest CP (19.25 %), ash (18.66 %), OMD (49.65 %), ME (7.25 MJ kg-1 DM) and NEL (4.16 MJ kg-1 DM) were obtained by the treatment of 200 kg N ha-1. The control treatment had the maximum values of NDF (35.24 %) and CF (2.25 %). Water-soluble carbohydrates (WSC) increased by use of N fertilizer from 0 to 100 kg N ha-1, but more fertilizer consumption decreased its value. In general, the nitrogen fertilizer at the rate of 150 kg N ha-1 can be recommended as the best treatment to obtain high-quality silage.