Influence of compost fertilizer on some photosynthetic parameters of lentil (Lens culinaris Medik.) in three growth stages under drought stress

Compost produced from municipal waste and has suitable chemical and physical properties, which plays an important role in reducing the negative effects of environmental stress in plants. In order to evaluate the effects of compost fertilizer on photosynthetic parameters of phonological stages of lentil under drought stress, a factorial experiment in completely randomized design was conducted with three replications (p≤0.05). Experiment were carried out with five ratios of compost to soil, i.e., 0:100, 5:95, 15:85, 25:75 and 35:65, and three levels of drought stress including non-stress, moderate and severe drought stress (100, 75, and 25% of field capacity, respectively). Results showed that,adding 25 and 35% compost to the soil at seedling stage under moderate stress, led to significant increase of total chlorophyll content (12 and 15%), intercellular CO2 (8 and 8%), net-photosynthesis (16 and 17%) and efficiency of PSII (4 and 4%), compared with the control. However, under severe stress, it was effective levels of 35% compared with other levels. At flowering stage, 25 and 35% compost levels under moderate and severe stress led to significant increase in all parameters compared with control group. According to the results, this study suggests that compost plays an important role in reducing the negative effects of stress on photosynthetic performance of lentil, especially in the early stages of growth.