The effect of bacterial inoculation and cow manure on physiological indices, grain yield and yield components of chickpea (Cicer arientum) under drought stress conditions

IntroductionGrain of legumes, by having high protein percentage, is quality complementary of cereals grain. Among environmental stresses, water deficit is the most important factor which cause limitation of planting and yield loss of food crops. Organic fertilizers, in addition to the nutritional properties, are effective in improving the physical and biological properties of soil. According to the positive outcomes of using rhizobim inoculants including, increasing the quantity and quality of the crop, improving growth indices, reducing nitrate concentration in agricultural products and groundwater and environmental protection, this research was designed and conducted to investigate the effect of bacterial inoculation and cow manure on characteristics of chickpea (Hashem variety) under drought stress conditions, and promotion of environmentally friendly fertilizers.
Materials and methodsThe experiment was done during 2012-2013 growing season at the research field of the faculty of agricultural, Shahrekord University as split factorial in a Randomized Complete Block Design (RCBD) with 3 replications. Levels of drought stress including: 80, 100 and 120 mm evaporation from class A pan, were used as main plot factor while factorial combination of cow manure at three levels 0, 50 and 100% of plant complete need (20 ton/ha) and two levels of seed bacterial inoculation (Mesorhizobium) (inoculation and non-inoculation) were used as sub-plots. To determine the time of irrigation, the daily evaporation from evaporation pan was measured every evening and after reaching the desired level, irrigation was performed using flushing procedure.
Results and discussionThe results showed that by increasing drought stress intensity, the rate of crop growth rate and leaf area index was decreased. CGR and LAI significantly increased in inoculation treatment compared to non-inoculated. Means comparison showed that with increasing stress intensity, all of the yield components significantly decreased but grain protein percentage increased. Increasing consumption of cow manure and inoculation of bacteria caused increasing of grain yield components and its protein. Means comparison of the dual effects of drought stress × bacteria inoculation showed that bacterial inoculation significantly increased the number of pods per plant at all drought stress levels. Means comparison of the dual effects of cow manure × bacteria inoculation showed that inoculation caused increasing the number of pods per plant at all cow manure levels. The maximum hundred seed weight achieved at 20 tons/ha of cow manure treatment and bacterium inoculation. The results of the triple effects showed that the maximum hundred seed weight achieved at control × 20 tons/ha of cow manure × bacterium inoculation. With increasing severity of drought stress, grain yield and biological yield significantly decreased. The maximum and minimum grain and biological yield on the consumption of cow manure obtained in 20 tons of cow manure per hectare and no use of cow manure, respectively. Bacterial inoculation was significantly increased grain and biological yield. The results of the dual effects of cow manure × bacterium inoculation on grain yield, biological yield and harvest index showed that the maximum mean of grain and biological yield obtained at no use of cow manure × bacterium inoculation. The results of the triple effects on grain yield showed that the maximum grain yield achieved at bacterium inoculation × no use of cow manure × control.
ConclusionGenerally in this study it can be stated that the treatment of drought stress and bacterium inoculation have more effect on physiological indices, yield and grain yield components of chickpea. Drought stress causing reduction of photosynthetic sources and limitation of assimilate and thus leads to reducing hundred grain weight and leaf area and thus slow down the crop growth rate. In this experiment, it was found that the use of bacteria in drought stress conditions cause adjusting the effects of stress, therefore it is suggested that in areas where there is a likelihood of drought stress, the inoculated seeds should be used.