The effect of biological and chemical nitrogen fertilizer on yield and yield components of improved chickpea varieties under rainfed conditions

Excessive use of chemical fertilizers for increasing agricultural production causing environmental damage and disturbance in the soil fertility. Currently, biological approaches for improving crop production are gaining strong status among agronomists and environmentalists following integrated plant nutrient management system. Chickpea is the most important pulse crop which is grown on 463,000 hectares in Iran. Major chickpea areas (98%) are planted under rainfed condition and are grown in rotation with cereals mainly wheat and barley. Mean productivity of chickpea 402 kg/ha in 2014-15 cropping season in Iran. One of the reason for low chickpea productivity in Iran, is unsuitable using nutrition in chickpea farms. Currently biologic fertilizers as an alternative option for chemical fertilizer to enhance to soil fertility in the stable agricultural production are considered. Rhizosphere beneficial bacteria are commonly called plant growth promoting rhizobacteria (PGPR) and have been under researchers focus for many years. PGPRs can stimulate plant growth through different mechanisms. Solubilization of inorganic phosphate is a characteristic has been frequently used for screening these bacteria. The objective of present study was to investigate the effect of biological and chemical nitrogen fertilizers on yield and yield components of improved chickpea varieties.

An experiment was carried out in factorial based on a randomized complete block design with four replications and five fertilizers treatments (control, Super Nitro Plus, Nitroxin, Rhizocheck and 30 kg nutrition fertilizer per hectare) and three chickpea varieties (Azad, Hashem and Arman) in Ekbatan Research Station of Hamedan under rain-fed condition during 2012-2013. Rhizocheck had 107 bacteries from Pseudomonas putida and 108 Mesorhizobium cicero and Super Nitro Plus included 108 Bacillus subtilis, pseudomonas fluorescens and different species of Azospirillum. Also Nitroxin covered 108 nitrogen fixing bacteries such as Azotobacter and Azospirillum. During vegetative and reproductive phases, weeds were controlled and data were recorded on days to flowering, days to maturity, plant height, harvest index, number pods per plant, number of seeds per pod, 100-seed weight, and seed yield. Data were analyzed using the SAS. Ver. 9.1 and figures were drawn by EXCEL and means compared by using DMRT at the 5% probability level.
 

The results showed that fertilizer had significant effects on harvest index and seed yield at 1% level of probability. But fertilizer treatment had not significant effects on days to flowering, days to maturity, leaf area index, plant height, pods number per plant, seeds number per pod and 100-seed weight. Also the results showed that varieties showed significant difference for days to flowering, leaf area index, harvest index, seeds  number per pod, and seed yield. Varieties had not significance different on days to maturity, plant height, number of pod per plant and 100-seed weight. Interaction of fertilizer × variety on all characters was not significant. The result of mean comparison showed that the highest seed yield has been produced by Rhizochick consumption. The utilization of Rhizocheck had result in 39 and 26 percent higher harvest index and seed yield than control, respectively. Azad variety had the highest leaf area index, harvest index and seed yield. The lowest leaf area index, harvest index and seed yield was observed on Hashem variety. Stephan (2000) reported that 36 percent seed yield increased due to rhizobium inoculation on chickpea seed. Maximum seed yield was achieved in Azad variety with Mesorhizobium of SWRI-15 which produced 151 percent higher than check. Rhizobium inoculation in comparison with no inocultion on chickpea seed under drought stress condition increased seed yield. Most of scientists reported that using biological fertilizers have been effected on seed yield in comparison with check on lentil, sunflower, wheat, corn and pearl millet.
 

One of the most important factors for soil fertility is microorganism ability for production and plant growth promoting. The result of present study showed the highest productivity obtained from Rhizochick consumption. Azad improved chickpea variety produced the highest seed yield. Rhizochick may cause photosynthesis intensive activity and enhancing availability elements. Therefore seed yield have been increased. Generally, PGPR promote plant growth directly by either facilitating resource acquisition (nitrogen, phosphorus, essential element) or modulating plant hormone level. The reduction chemical consumption will affect decreasing environment contamination which is one of the important factors for stability agriculture. Therefore Azad improved chickpea variety with Rhizochick inoculation in Hamaden province is recommended.