effect of different nitrogen fertilizers and various mulches rates on yield and yield components of garlic (allium sativum l.)

in order to investigate the effects of nitrogen application rates and different planting beds on yield and yield components of garlic (allium sativum l.), a field experiment was conducted as split plot based on a randomized complete block design with four replications at the agricultural research station, azad university of torbat-e-jam, iran, during 2009-2010. three nitrogen application rates (0, 50 and 100 kg.ha-1) and seven planting beds (20 and 40 t.ha-1 manure, 20 and 30 t.ha-1 sand and 5 and 10 t.ha-1 wheat straw and control) were allocated to the main and the sub plots, respectively. results indicated that the simple effects of nitrogen application rate and planting bed were significant (p≤0.05) on the leaf dry weight, bulb number, economical yield, biological yield and hi of garlic. also, the interaction between nitrogen application rate and planting bed had not significant effect. by increasing in 50 and 100 kg nitrogen ha-1 enhanced economical yield of garlic up to 15 and 20%, respectively. the highest garlic economical yield was observed in 40 kg manure (1085.4 g.m-2) and the lowest was for control (723.5 g.m-2). there was a positive correlation between leaf weight and bulb number with economical and biological yield of garlic. it can be concluded that the agronomic operations enhanced growth characteristics and bulb number of garlic. it seems that increase economical and biological yields of garlic was due to improvement of its growth characteristics and bulb numbers.