​The Effects of Mesorhizobium ciceri Inoculation and Different Doses of Vermicompost Treatments on the Yield Components and Yield of Chickpea (Cicer arietinum L.) under Semi-arid Mediterranean Highland Condition of Turkey

The research was carried out in the experimental area of Siirt University during 2016 and 2017 spring growth seasons. Siirt province is at the altitude of 902 m, located in the Southeastern Anatolia Region on 41°57' east longitude and 37°55' north latitude. Trial area is in fertile crescent and 180 km away to Karacadag Mountains (Diyarbakir) where Einkorn wheat (Aegilops monococcum L.) was first cultivated in history approximately 10 thousand years ago.
       
Azkan variety chickpea seed was used in the experiment. Azkan variety has upright growth habit, medium level branching, early maturing and drought and cold tolerant (Anonymous, 2019).
       
Mesorhizobium ciceri bacteria were used for inoculation and vermicompost (prepared from 70% cow manure and 30% vegetable waste) were used as organic fertilizer in the study. Vermicompost was excrete of red California worms (Eisenia foetida) (pH 6.5-8.5; organic matter content 35%, total N content 1.2%; Ekosol brand; Turkey). Mesorhizobium ciceri bacteria was used as microbial inoculant which was obtained in a peat culture medium from the “Soil Fertilizer and Water Resources Central Research Institute” (Ankara, Turkey). Dose for Mesorhizobium ciceri inoculant applied to seeds was 10⁸ cfu per seed. Soil of the trial field was clayey-loam, nearly flat, poor in organic matter (1.02%), salt-free (0.40 dS m^-1), calcareous (CaCO₃, 0.48%), slightly alkaline (pH: 7.6), rich in potassium content (660 kg ha^-1) and rich in phosphorus content (33.3 kg ha^-1).
       
Terrestrial climate exist in Siirt with hot and dry summers and with common precipitation between March and June. Agroclimatic characteristics of Siirt province are suitable for chickpea cultivation. Meteorological data of the trial area is given in Table 1.
 

       
Average temperature was similar to the long-term average in the first year, while it was 1.4°C lower in the second year. Annual rainfall in 2016 and 2017 remained below the long term average. Relative humidity values were approximated to the long term averages (Table 1).
       
The trials were set up on three replications according to the randomized complete blocks design. Sowings were conducted in the first week of March, on four rows in each plot, on 5 m long rows, with 30 cm inter-row spacing and at sawing density of 60 seeds/m². Before planting, total 0, 1000, 2000, and 3000 kg ha^-1 doses of vermicompost were spread on the parcels before harrowing.
       
Plant seeds were soaked in water containing sugar at 4% concentration, hold 10 seconds and then put into bacteria carrier peat media for inoculation with Mesorhizobium cicero bacteria with dose of 1 kg peat culture/50 kg seeds (at 10⁸ cfu bacteria per seed). Seeds were mixed in peat-inoculant media approximately 1 minute. These procedures were conducted in a shadow condition in the morning before 3 hours of seed sowing.
       
Rainfed chickpea cultivation technique was applied. No irrigating was applied. Weed control was done mechanically. For observation and harvesting, one row from the edges of the plots and 0.5 m from the both ends of the plots cut out. 10 plants selected from the remaining plants for observations, except grain yield parameter. For plant height, distance between shoot to soil levels were measured. For first pod height, distance between first pod to soil levels were measured. Parcel harvest was conducted for yield determinations. Plant height, first pod height, number of pods per plant, number of seeds per plant, 100-grain weight, and grain yield were recorded.
       
Pesticides against anthracnose was applied at three times in 2017 and one time in 2016. The plants were harvested in the first week of July when the pods are dried and the grains were hardened. Harvesting and threshing operations were done manually. The data were subjected to variance analysis and differences between the applications were determined by the Tukey^(0.05) test via JMP (version 5.0.1) software program.

The effects of years and applications on plant height, first pod height and the number of seeds per plant were statistically significant. The effects of years, applications, and year × application interaction on the number of pods per plant, 100-grain weight, and grain yield were statistically significant (Table 2 and 3).
 

 

       
Plant heights were between 56.1-61.9 cm, first pod heights were between 29.4-34.9 cm, pod number per plant values were between 31.4-46.3, number of seeds per plant values were between 32.9-44.0, 100-grain weight values were between 30.4-37.4 g and grain yields were between 1463-2072 kg ha^-1 (Table 2 and 3). Values for all parameters were lower in 2017 than in 2016. In 2017, anthracnose disease negatively affected the vegetative and generative growth of plants. Pesticides were used against anthracnose disease once in 2016, and three times in 2017. Depending on this disease, plant heights were shorter, and grain yields were lower in 2017 compared to 2016. The highest values for all parameters were obtained from Mesorhizobium ciceri + 1000 kg ha^-1 vermicompost application. This was followed by applications of sole 1000 kg ha^-1 vermicompost and sole 2000 kg ha^-1 vermicompost.
       
The lowest values were detected by Mesorhizobium ciceri + 3000 kg ha^-1 vermicompost application. Siirt province is located in the gene center of the chickpea. South Eastern Anatolia is in gene origin zone of chickpeas and soils naturally contain Mesorhizobium ciceri bacteria (Erdoðan, 1997). However, the number and nitrogen-fixing capacity of these bacteria are unknown. The organic matter content of Siirt province soils is low. However, if the nitrogen content in the soil increases to excess levels, the microbial activities of Mesorhizobium ciceri bacteria may decrease (Uyanýk et al., 2011). Mesorhizobium ciceri bacteria inoculation and vermicompost application exceeding 1000 kg ha^-1 resulted a decrease in the growth parameters. When the effect of year × application interaction on the number of pods per plant, 100-grain weight, and grain yield was examined, the highest values were obtained from Mesorhizobium ciceri + 1000 kg ha^-1 vermicompost application in 2016. The lowest values of all parameters were detected in Mesorhizobium ciceri + 3000 kg ha^-1 vermicompost application in 2017. Mesorhizobium ciceri inoculation produced medium values between co-application of 1000 kg ha^-1 vermicompost with Mesorhizobium ciceri and control and excess vermicompost applied conditions.
       
Uçar et al., (2020) reported that vermicompost application increased chickpea plant height, first pod height, pod number per plant, number of grain per plant, 100-grain weight and grain yield in their study. Kumar et al., (2014) reported that vermicompost applications increased plant height, pod number per plant, 100-grain weight, and grain yield compared to control.  Gopalakrishnan et al., (2014) and Amiri et al., (2016) determined that vermicompost applications increased the plant height of the chickpea plants and the number of pods. Uçar and Erman (2020), Soysal and Erman (2020) determined that Mesorhizobium ciceri bacteria inoculation was increased the plant size of chickpeas. Pashaki et al., (2016) reported that microbial fertilizer and vermicompost application increased the number of pods, the number of seeds, and the grain yield. Similar results were also determined by Singh et al., (2012) and Bhattachariya and Chandra (2013) for the chickpeas at different location.

Significant effects were determined by vermicompost application and Mesorhizobium ciceri bacteria inoculation on grain yield and yield components. The highest values for all characteristics were obtained by Mesorhizobium ciceri + 1000 kg ha^-1 vermicompost application. The effect of Mesorhizobium ciceri + 2000 kg ha^-1 vermicompost and Mesorhizobium ciceri + 3000 kg ha^-1 vermicompost applications on the parameters were lower than the control.
 
As a result of the study, Mesorhizobium ciceri inoculation + 1000 kg ha^-1 vermicompost application was recommended in the chickpea cultivation in the ecological conditions of Siirt province in Turkey and in similar ecologies.