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
Plate 1: LBG-791 black gram variety free from yellow mosaic disease.
Plate 2: T-9 black gram variety susceptible to yellow mosaic disease.
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).
Table 2: Effect of front line demonstrations on growth and yield parameters of blackgram variety LBG-791 under rainfed conditions.
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.
Table 3: Yield performance and gap analysis of blackgram variety LBG-791 under rainfed conditions.
Technology gap, extension gap and technology index
Fig 1: Grain yield as effected by YMI in black gram varieties.
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).
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
Table 4: Economic analysis in blackgram variety LBG-791 under rainfed conditions under FLDs.
• 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.