Effect of plant density on yield and seed yield components of forage vetch in rain-fed and supplemental irrigation conditions

In order to study effect of plant density on yield and seed yield components of forage vetch in rain-fed and supplemental irrigation conditions, two separate experiments were conducted at the research filed of faculty of agriculture, Lorestsn University, during 2008-2009. Three species of forage vetch (Vicia narbonensis, V. sativa and V. dasycarpa) and in three plant densities (100, 150 and 200 plant/m2) were combined factorially based on a randomized complete block design in each experiment. The highest dry forage yield (4912 kg/ha) was found in V. sativa under rain-fed condition and 150 plant/m2. Also the lowest dry forage yield (1750 kg/ha) was found in V. dasycarpa under supplemental irrigation condition and 100 plant/m2. The highest and the lowest pods yield (4282 and 1426 kg/ha) were recorded under supplemental irrigation condition and 100, 150 plant/m2 for V. narbonensis and V. dasycarpa, respectively. The highest and the lowest seed yield (3352 and 3/870 kg/ha) were recorded under supplemental irrigation condition for 200, 150 plant/m2 for V. narbonensis and V. dasycarpa, respectively. The highest and the lowest 1000 grain weight (133.10 and 29.73 gr) were recorded under supplemental irrigation condition for 100, 200 plant/m2 for V. narbonensis and V. dasycarpa, respectively. The highest biological yield (8243 kg/ha) was found in V. sativa under rain-fed condition and 150 plant/m2. Also the lowest biological yield (3268 kg/ha) was found in V. dasycarpa under supplemental irrigation condition and 150 plant/m2. The maximum and the minimum harvest index (52/82% and 21/10%) were recorded under rain-fed condition for 100, 150 plant/m2 for V. narbonensis and V. dasycarpa, respectively. The 1000 grain weight of the two experiments were significantly different using T- test (P 1%) and dry forage yield and harvest index of the two experiments showed significant difference using T-test (P= 5%).