Effect of Variable Sowing Ratios and Sowing Rates of Bitter Vetch on the Herbage Yield of Barley-bitter Vetch Mixed Cropping

摘要

Field trials were carried out at the Jordan University of Science and Technology in Northern Jordan to determine whether mixtures of bitter vetch with barley would change vetch and total yield in a competitive or facilitative way related to sowing proportions based on number of seeds. Ratios of the number of vetch to barley seed were 100:0; 85:15; 70:30; 65:45 and 40:60 within each mixture, sowing rates of bitter vetch were 80, 100, 120 and 140 kg ha ^-1. The barley was sown at 150 kg ha ^-1. Plants were harvested at the pod setting stage of vetch. Relative yield total of both crops was used as the parameter for mixed stand advantage. Mixed cropping produced 96% more dry matter than the sole cropping of vetch, but 63% less than the barley sole cropping. Mixed cropping yields were not simulated by sowing ratio or sowing rate of vetch but proportions of vetch dry matter decreased linearly as the percentage of barley seed in the mixture increased. The data suggested the possibility of greatest vetch yield with barley proportions below 15%. If high herbage yield is the objective, the barley sole crop will be selected. Crude protein content regardless of herbage yield should not be a criterion to define the best sowing rate of barley-vetch mixture. High forage quality of the mixed cropping would require a very low sowing proportion of barley to increase vetch contribution to forage yield.