عنوان مقاله [English]
Background and objectives
The Oilseeds after cereal, the world's second largest food supply make up. Environmental stress has always been one of the most important factors reducing crop yield and production are gone and Counter or reduce the effects of stress as a useful strategy to increase the quality and quantity of the products has been considered. Flooding conditions are said to be part of the stem plant below the water. Flooding stress is limiting growth and yield of cropsespecially in humid regions. Cause changes to be in yield components, pod capacity, biological yield and seed yield in oil plants. Given that soybean one of the main plants oil is the country's, Identifying the factors that to be cause flooded stress and thus reduce soybean yield, It is necessary. In order to investigate the effects of flooding period and type of nitrogen nutrition on quantitative and qualitative traits of soybean (Glycine max (L.) Merr), an experiment was conducted at Gorgan University in 2012.
Materials and methods
The experiment with factorial arrangement in a completely randomized design with three replications was conducted for pot (For each treatment, 3 pots, each pot there was considered a repeat). Treatments include dietary treatments at three levels of nitrogen (1. Do not inoculated plus nitrogen2. Inoculated with bacteria (Bradyrhizobium japonicum)3. Non-inoculated without fertilizer), severely flooded in four levels (0, 5, 10 and 15 days ) and the stress flooding reproductive stage (R2), respectively. In this experiment, yield, yield components, oil content and seed protein were measured.
Seed yield and oil content in nutrient levels, during flooding was decline, but the protein was increased. There was a significant difference (α=0.05) between dietary levels of yield, oil content and seed protein. The highest seed yield (3.32 gram per plant) and seed oil content (26.3 percent) was in the treatment of non-inoculated with bacteria and feed fertilizer in the absence of flooding. The lowest seed yield (1.2 g per plant) and seed oil content (11 percent) in the treatment of non-inoculated with bacteria and no fertilizer was achieved in 15 days of flooding. Highest protein content (37.39 percent) was treated with fertilizer and without inoculation with bacteria at 15 days of flooding and the lowest (93.16 percent) was observed in the treatment of non-inoculated and fertilizer and flooding.
The results showed that by reducing the amount of available nitrogen for plants and increasing the flooding, seed yield and oil content reduced and seed protein content increased with increasing the stress time. The results also showed that the use of urea fertilizer, significantly increase seed yield in compared to when soybean plants inoculated just by bacteria.