Growth, yield components and yield of groundnut
The results of groundnut + Bt cotton intercropping system showed that significantly higher numbers of branches per plant, number of pods per plant and 100 kernel weight of groundnut were registered under sole crop. Maximum number of branches per plant (7.33), number of pods per plant (22.72) and 100 kernel weight (60.86 g) was recorded in treatment of 100% RDF to groundnut crop (T
3) which was remained at par with sole groundnut(100% RDF) 3:1 row Skip (T
6) but significantly higher than rest of treatments. Fertilizer application might have increased the amount of available nutrients, which encouraged the production of more number of flowers, gynophores and matured pods. Similar observations were reported by
Koraddi et al., (1991) who found that the growth and yield attributes of groundnut were significantly reduced in intercropping system against sole crop. This might be attributed to the competition for available nutrients and shading effect under intercropping situation
(Sathyapriya et al., 2009). There was no significant difference in oil content of groundnut because of different nutrient management practices to component crop of cotton.
Pod and haulm yields of groundnut were significantly influenced by different treatments (Table 1 and 2). The maximum pod yield (1808, 1982, 2037 and 1942 kg/ha, respectively) was recorded by sole groundnut with 100% recommended dose of fertilizer treatment (T
3) during the years 2012-13, 2013-14, 2014-15 and in pooled, which was at par with T
1 and T
2 during individual years and T
2 in respect of pooled data. In respect of haulm yield, it was found significant during the year 2014-15 and in pooled. Significantly higher haulm yield (3137 and 2822 kg/ha, respectively) was recorded by sole groundnut with 100% RDF (T
3) during 2014-15 and pooled results. No significant differences were found in haulm yield during the years 2012-13 and 2013-14. This was in accordance with the finding of
Koraddi et al., (1991) that growth and yields attributes were significantly reduced in intercropping system. It also emphasized that the better performance of sole crop of groundnut could be attributed to more assimilation and distribution of photosynthates were mainly responsible for more number of pods/plant, higher dry matter production and yields of groundnut in sole cropping.
In intercropping situation, application of 100% recommended dose of fertilizer to groundnut and cotton individually according their area basis produced higher pod yield of 1484 kg/ha which was closely followed by groundnut (100%RDF) +
Bt cotton (150%RDF) 3:1. The poor performance of groundnut in intercropping was mainly attributed to lower plant population (25% base population in intercropping as compared to sole groundnut). Further, the shading effect of cotton (90 days after sowing onwards) and competition for resources, particularly water and nutrients also contributed to lower values of yield attributes and yield.
Growth, yield components and yield of Bt cotton
Nutrient management practices in intercropping system had pronounced significant effect on the plant height, number of bolls per plant and monopodial branches per plant in pooled results. The higher plant height (142.5 cm), bolls per plant (44.45) and monopodial branches per plant (4.31) were recorded in treatment of 150% recommended dose of fertilizer to sole
Bt cotton but, it was at par with 100% recommended dose of fertilizer. This higher yield in sole crop might due to the competition free environment as compared to intercropping system. In intercropping situation, the plant height, number of bolls per plant and monopodial branches per plant increased with higher levels of fertilizer to intercropping system. Significant differences were found in cotton yield in pooled results (Table 1) while stalk yield, significant differences was recorded during the year 2014-15 and in pooled results (Table 2). Significantly the highest cotton yield (2296 kg/ha) and stalk yield (3002 kg/ha) was recorded by sole cotton with 150% RDF treatment (T
8) in pooled results. Groundnut as an intercrop with short and compact stature did not offer competition to cotton and thus the growth condition of cotton in both sole and intercropping was identical. The positive impact of inclusion of groundnut as an intercrop owing to its ability of biological N fixation and reducing weed menace in between cotton rows favoured development of yield attributes in cotton, leading to higher cotton yield. These results are in agreement with those of
Koraddi et al., (1991), Sathyapriya et al., (2009), Singh and Ahlawat (2011) and Honnali and Chittapur (2014).
Groundnut pod equivalent yield
The groundnut pod equivalent yield was found significant during all individual years and in pooled results (Table 1). Significantly the highest groundnut pod equivalent yield (3910 kg/ha) was recorded by groundnut with 100% RDF +
Bt cotton with 150% RDF in 3:1 row ratio proportion (T
14) in pooled results, which remained at par with treatments
viz., T
9, T
10, T
11,T
12 and T
13. Higher crop equivalent yield under intercropping system showed an efficient utilization of resources resulting in better productivity of component crops in the system. This study as indicated that the base crop yield reduction was well compared with the intercrop yield. The results are in agreement with the findings of
Sathyapriya et al., (2009) and Kalaghatagi and Guggari (2010).
Economics
Monetary returns for the inter-cropping system are presented in Table 3. All the intercropping treatments recorded higher gross and net return per hectare than sole crops of either groundnut or cotton. Gross realization, cost of cultivation, net realization and B:C ratio of different treatments were worked out on the basis of current market prices of groundnut and cotton inputs used. The highest gross realization (₹ 145251/ha) and net return (₹ 88871/ha) with B:C ratio of 2.58 was recorded in intercropping of groundnut and
Bt cotton in 3:1 row proportion with 100% recommended dose of fertilizer for groundnut and 150% recommended dose of fertilizer for
Bt cotton. Similar experimental results have been reported by
Koraddi et al., (1991).
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