Impact of Large Scale Demonstration on Productivity and Profitability of Blackgram Under Rainfed Conditions of Chamarajanagara District, Karnataka (Zone-6)

Among different pulse producing countries, India is one of the largest producers of pulses. Pulses play a crucial role in maintaining the nutritional security and soil health. In Indian diet most importance has been given to pulses next to cereals, as they are rich in protein and essential nutrients. Black gram (Vigna mungo) a short duration legume crop belongs to the family Fabaceae flourishes well in all seasons either as sole or as intercrop. In India, blackgram occupies an area of 44.93 lakh ha with a production and productivity of 29.26 lakh tonnes and 651 kg/ha respectively. However in Karnataka, the area, production and productivity were 3.02 m ha, 1.86 m t and 614 kg/ha, respectively (Anonymous, 2017). The Chamarajanagar district is a border district of Karnataka having varied agro-climatic conditions with diversified cropping situation. Among different pulses grown in district, black gram occupies major area next to horsegram and greengram. The district productivity of black gram is 203 kg/ha (Anonymous, 2018a). There is a huge yield gap in district when compared to national and state productivity. The reasons for yield gap were non-availability of season based quality seeds and disease tolerant varieties resulted in increased pest and disease incidence particularly yellow mosaic virus disease, use of local and photo insensitive varieties followed by erratic rainfall, cultivation of crops under poor and marginal lands, broadcasting of seeds, no seed treatment with bio-fertilizers (Rhizobium and PSB), not practicing application of micronutrients, Poor management practices of pests and diseases (Anonymous, 2018b). In this context, the large scale demonstration of integrated crop management practices in blackgram variety LBG-791 was demonstrated with an objective of enhancing the productivity and profitability of farmers of Chamarajanagara district. 

The study was carried out through conducting training programmes, method demonstrations and front line demonstrations (60 ha for 150 farmers) during Pre-kharif 2020-21 to 2022-23 in K. Mukahalli, Kotamballi, Devalapura, Doddatuppuru and Y.K. mole villages of Chamarajanagar district of Karnataka state for dissemination and popularization of the technologies. Group meetings were conducted in selected villages where the problem prevailed with respect to production technologies before demonstration. The interested farmers were opted to conduct the demonstrations after the group meeting (Choudhary, 1999).
 
Details of critical inputs provided
 
Blackgram variety (LBG-791):08 kg; Rhizobium and PSB bio-fertilizer: 200 g each; Zinc sulphate: 4 kg; Carbendazim: 500 g; Chloropyriphos: 500 ml were provided for all the 150 beneficiaries (0.4 ha/farmer).
 
Details of technologies
 
The package of improved technologies like line sowing, integrated nutrient management includes micro nutrient application (Zinc sulphate), integrated weed management, seed treatment with systemic insecticides, rhizobium and PSB and whole package were demonstrated as mentioned in Table 1. University of Agricultural Sciences, GKVK, Bengaluru developed a new blackgram variety namely LBG-791 (Suraksha) during 2019. It is a short duration (70-75 days) variety with yellow mosaic disease resistance with a yield potential of 900-1000 kg/ha under rainfed and 1200-1500 kg/ha under irrigated condition was opted for demonstration against farmers’ variety T-9 short duration (70-75 days) susceptible to yellow mosaic virus disease.
 

       
Observations on different growth (plant height, number of branches) and yield parameters (number of pods per plant, number of seeds per pod and 100 seed weight) were taken from five randomly selected plants. Yellow mosaic disease incidence (%) was calculated by counting the number of plants infected and total number of plants in a one meter square area separately (Archana et al., 2018). The yield data were collected from both the demonstration and farmers practice by random crop cutting method and economics assessment was done as per prevailing market prices. Cost of cultivation, gross returns, net returns and B:C ratio were calculated as per the procedure outlined by Saravanakumar (2021). Improved blackgram growing technologies were introduced to targeted farmers through extension approaches through regular follow up field visits, on and off campus training programs to farm men and women, interactions, group discussions and through distribution of technical bulletins on Integrated crop management in blackgram. Further field days were organized by inviting the farmers from other nearby villages and media coverage was also done to reflect the maximum impact. The technology gap, extension gap and the technology index were calculated by adopting suitable formulae (Singh et al., 2022 and Sunil et al., 2020).
 
Extension gap= Demonstration yield - farmers’ practice yield.
 
Technology gap= Potential yield - demonstration yield.
 
 
 
 
 
Statistical analysis
 
Further statistical analysis (Z test for two mean) was done for all growth parameters, yield parameters and grain yield and yellow mosaic disease incidence to check the level of significance (Das and Giri, 2003). The response of blackgram variety LBG-791under rainfed condition of Chamarajanagar district was similar in all the years. Therefore, only mean data of three years was discussed.

Assessment of gaps
 
The information collected by survey on technology adoption showed that there was a huge gap between demonstrated technologies when compared to farmers’ practices (Table 1). The cultivation of local and unsuitable varieties for the zone by the farmers is one of the major causes for getting lower yield. The seed rate used by the farmers showed that 20% of the farmers used the recommended seed rate whereas 80 per cent of the farmers were using 25-30% extra seed rate. The information further revealed that 60 per cent of the farmers were following broadcasting method of sowing and rest of the farmers followed line sowing. Seed treatment for pest and disease management was not a common practice. 100% farmers were not following the seed treatment and therefore, there was a huge gap of 100%. Fertilizer usage pattern was also not proper at farmers’ level. 90% of the farmers were not using potassium as well as zinc sulphate. Further 100% farmers were lack of knowledge about foliar spray of DAP @ 2%. Recommended dose of fertilizers was applied only by 10% of farmers. Biofertilizers (Rhizobium and PSB) play a crucial role in enhancing the yield of blackgram. The information on biofertilizers use revealed that 100% farmers were not using biofertilizers. Weed management plays an important role in deciding the yield under rainfed conditions. At present situation timely availability of labours has become a major problem in turn resulted in high weeding cost. Hence hand weeding is a risky task for timely weeding. Therefore Integrated weed management is a best option in curbing the weeding cost (Table 1). Incidence of sucking pests viz. white fly, jassid, etc. was another major factor affecting crop yield adversely. The practices for management of sucking pests were adopted only by 20-25% of the farmers. Similarly, disease management practices were not adopted by majority of farmers.

Yellow mosaic disease incidence and growth and yield parameters
 
An optimistic response from the blackgram growers of Chamarajanagar was obtained about the new variety and agricultural technologies as they have got good results from the front line demonstrations (FLD). The per cent incidence of yellow mosaic virus disease was significantly higher with local variety (Plate 1) as compared to LBG 791 (Plate 2) presented in Table 2. These results may be attributed by biochemical compounds on the leaves, which repelled insects from host plant (Taggar et al., 2014). On the other hand, physical factors such as leaf area, pubescence and lamina thickness must also be taken into account regarding host selection and might play a role in imparting resistance in black gram plants to B. tabaci (Pavishna et al., 2019 and Taggar and Gill, 2012).
 

 

       
The growth and yield parameters are presented in Table 2. Adoption of LBG-791 with improved crop management practices has recorded significantly higher mean number of branches per plant (4.3), number of pods per plant (41.5), number of seeds per pod (7.20), 100 seed weight (5.30 g) as compared to local variety with farmers practices (3.55, 27.5, 6.78, 4.16 g respectively). Whereas the plant height was significantly higher with local variety with farmers practice (53.6 cm) as compared to the LBG-791 with improved crop management practices (43.7 cm). This difference is mainly attributed to their genetic variability and varietal difference. Further reduced incidence of yellow mosaic disease also contributed for better growth and yield parameters. These results were in confirmation with findings of Patel et al., (2013) and Singh et al., (2018).
 

 
Grain yield
 
Grain yield of blackgram has varied in different years, which might be due to the soil moisture availability and rainfall condition, climatic aberrations, disease and pest attacks as well as the change in the location of trials every year (Naik et al., 2015 and Sing et al., 2022). However, the maximum grain yield was recorded with improved management practices with LBG-791 plots (FLD) as compared to farmers’ practice plots in all the three years (Table 3). The increase in yield in demonstration plots could be attributed to adoption of improved practices of crop production (Fig 1). The per cent increase in yield varied from 116.3% to 127.1% from 2020 to 2022, respectively.
 

 

 
Technology gap, extension gap and technology index
 
In demonstration plots the mean technology gap of 119 kg/ha was recorded (Table 3). Technology gap shows that there is need to create further awareness among the farmers about the improved crop management practices through various extension means Mukherjee (2003) and Mitra and Samajdar (2010). The higher mean extension gap of 379 kg/ha was recorded (Table 3). It may be due to higher yield of blackgram variety in demonstration plots. Adoption of new improved production technologies with new high yielding and disease resistance variety has helped in reducing the extension gap. These results were in conformity with Hiremath and Nagaraju (2010). Technology index showed the feasibility of the evolved technology at the farmers’ fields. Lower value of technology index meant more feasibility of disseminated technology. The mean technology index was 14.73 % (Table 3). This might be due to variations in soil fertility, environmental variation and infestation of pest and diseases (Sunil et al., 2020). Similar results were obtained with Mokidue et al., (2011), Kumar et al., (2018) and Singh et al., (2022).
 
 
Economics
 
Adoption of a technology purely depends on its economic feasibility (Table 4). The average cost of cultivation was higher in demonstration plot (₹ 23892/ha) as compared to farmers practice plot (₹ 20948/ha). Average gross and net returns of ₹ 48219 and ₹ 23345/ha, respectively was obtained with demonstrated plots as compared to farmers practices (₹ 21647 and ₹ 699/ha, respectively) and similar trend was also observed with B:C ratio. Higher benefit cost ratio in demonstration could be the result of higher yield due to adoption of improved practices which were missing in local check plots. The results confirmed the findings by Paramasivan and Selvarani (2017) and Sing et al., (2022).
 

 
Suggestions from FLD farmers for further adoption of technologies
 
• Farmers requested to make available of LBG-791 blackgram variety under seed chain with subsidy as it is costly to purchase directly from market.
• Farmers requested to make available the biofertilizers in Raita Samparka Kendras for easy access.
• Making availability of pre emergence herbicides in main centers of taluks for easy access and requested to conduct method demonstrations and training programs for further more knowledge about safe usage of herbicides.

Adoption of improved crop management practices along with LBG-791 a new short duration variety with resistance to yellow mosaic incidence has proven to be the best technologies in obtaining higher grain yield and given a new hope to other farmers of Chamarajanagar district and also helps in enhancing blackgram production and productivity through horizontal and vertical expansion.

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