Evaluation of Rabi Maize-based Intercropping System for Augmenting the Productivity and Profitability of Rabi Maize under Irrigated Conditions of Bihar

Maize (Zea mays L.) is the third most important cereal crop of the world after rice and wheat (Arya et al., 2015 and 2020). With a production of 1162.3 million metric tons and a productivity of 5.75 t/ha, maize is cultivated on 201.98 million hectares around the world. The world’s maize production has increased from 11 million metric tons in 2020–21 to 12.1 million metric tons in 2021-22 (ICAR–IIMR, 2022). India is the fourth largest producer of maize in the world in terms of total maize output, with an area of 9.89 m ha, production of 31.65 m tons and productivity of 3199 kg/ha (ICAR-IIMR, 2022). In Bihar, generally 70-80% maize is grown during the rabi season, which occupies an area of 0.46 million ha with production and productivity of 1.9 million metric tons and 40.81 q/ha, respectively (Anonymous 2021).
       
The intercropping system involves growing two or more crops concurrently on the same plot of land while maintaining a distinct row pattern (Ouma and Jeruto, 2010). It is typically used on small farms with few resources by small and marginal farmers and it has been seen to increase yields with greater stability in a variety of crop combinations (Maitra et al., 2021). Additionally, intercropping systems are known for their more effective use of water, land, nutrients and inputs such as fertilizers, plant protection chemicals, labor and reduction in weeds, resulting in healthy, safe and high-quality food produced in an environmentally friendly manner. (Awal et al., 2006). In addition to improving production stability, it also raises overall productivity and income per unit of land area. The vegetable pea is a significant legume crop and the main plant protein source for both humans and animals. Garden peas are a high-value, short-season (60-70 days), high-return crop that can be planted in the rabi season to increase cropping intensity without affecting maize growth and yield. Due to the low temperature at that time, the rate of rabi maize seed germination and plant growth is very low. The space between two rows of maize at an early stage may be utilized by planting of any short duration with dwarf nature crops as intercrops. Contrarily, maize is a long-lasting, widely spaced crop that matures in about 5 months and offers opportunities for intercropping for a quick return. A combination of maize and legume, cabbage and potato in intercropping benefits the agricultural production system due to different peak period of growth and synergistic effects, which reflected into yield advantage. In order to reduce nutritional competition and the yield gaps between actual production and production potential for both crops in the intercropping system, the present study was undertaken to find out the suitable rabi maize based intercropping system for augmenting productivity and profitability of maize.

Field experiments (on-farm trials) were conducted on rabi maize-based intercropping during the winter (rabi) seasons of 2020-21 and 2021-22 at farmer’s fields in three villages of Bhagalpur, Bihar, to validate, refine and popularize the technology developed at Bihar Agricultural University, Sabour, Bhagalpur (Bihar) and ICAR-Indian Institute of Maize Research (IIMR), Ludhiana, for enhancing the productivity and profitability of rabi maize-based cropping systems. A Participatory Rural Appraisal (PRA) was conducted to determine the root causes of the high production costs and low profit margins associated with rabi maize. The soils of the experimental plot was loam to clay loamy in texture, with average pH 7.5, organic carbon 0.39%, available N 201.0 kg/ha, available P₂O₅ 20.5 kg/ha and available K₂O 218.7 kg/ha. The fields with a similar cropping pattern of rice as the preceding crop in the previous season were selected for conducting the experiment to follow the homogeneity test. The experiment, comprising four treatments, viz., sole rabi maize (farmer’s practice), maize + potato (1:1 row ratio), maize + vegetable pea (1:2 row ratio) and maize + cabbage (1:1 row ratio), was arranged in a randomized block design (RBD) with five replications. All five farmers selected for experimentation were treated as replications. The unit plot size was 10 m × 10 m. The maize crop as well as all intercrops were sown in the third week of November after the harvest of rice during both years at a spacing of 45 × 15 cm and 60 × 25 cm for the sole crop and intercrops, respectively. Maize + potato and maize + vegetable pea were sown on a fresh raised bed and sole rabi maize and maize + cabbage were sown or transplanted on a flat bed. The maize crop was grown as an additive series (100 percent of its recommended population in pure stand) as the base or sole crop. Intercrops like potato, vegetable pea and cabbage were introduced into the base crop by adjusting or changing crop geometry. The maize crop, either alone or under intercropping of maize + potato, maize + vegetable pea and maize + cabbage, was fertilized with 150:75:75 N:P₂O₅:K₂O kg/ha and applied through urea, diammonium phosphate (DAP) and muriate of potash (MOP). Half the dose of N and the full dose of P₂O₅ and K₂O were applied as basal and the remaining half dose of N was applied as top dressing in two equal splits at knee height and tasseling initiation stages of the maize crop. Additionally, no extra nutrients were added to the intercrops. For healthy maize and intercrops, all advised cultural practices were followed. Based on the minimum support price or the current market rate of the products, the maize-equivalent yield and monetary values of crops were calculated. In order to determine the economic variability of each cropping pattern, a benefit-cost ratio (BCR) analysis was also done. The benefit-cost ratio (B: C ratio) was expressed as the ratio of net returns to the cost of cultivation.

Effect of intercropping on growth, yield attributes and yield of maize
 
The growth and yield attributing characters of maize, viz., plant height, dry weight, number of grains per cob, cob length, cob girth and 1,000-seed weight, were significantly influenced by the involvement of various intercrops with rabi maize (Table 1). Maximum plant height (205.8 cm), dry weight (295.8 g), number of grains/cob (457.5), cob length (13.90 cm), cob girth (10.11 cm) and 1,000-seed weight (253.8 g) were recorded under the sole crop of maize, which was statistically at par with all intercrops, i.e., maize + potato (1:1 row ratio), maize + vegetable pea (1:2 row ratio), except maize + cabbage (1:1 row ratio). It was also recorded that the sole crop being statistically at par with maize + vegetable pea and maize + potato produced the highest grain yield of maize (93.5 q/ha) than maize + cabbage, which gave the minimum grain yield (88.1 q/ha). The yield of intercrops was reduced significantly when compared to their respective sole maize crop. The results are in confirmation with the findings of Sultana et al., (2013) in maize + legumes in intercropping and Shweta et al., (2022) in various maize cropping systems. Among the intercrops, maize + vegetable pea gave the maximum grain yield of maize (92.7 q/ha). The higher grain yield in maize under the maize + vegetable system might be due to the synergistic effect of vegetable pea with maize or minimum crop competition; however, the reduction in grain yield of maize under maize + cabbage intercropping may be due to more crop competition of cabbage with maize intercropping. Similar results were also observed by Singh et al., (2000) and Mishra et al., (2001), Pawar et al., (2011), Sarker et al., (2013), Khanum et al., (2019), Hashim et al., (2015), Landschoot et al., (2024), Begam et al., (2024), Li et al., (2023), Talukdar et al., (2022), Sahoo et al., (2024), Singh et al., (2023), Prakash et al., (2024) and Panda et al., (2021). Maize + vegetable pea (1:2 row ratio; maize planted at 60 × 25 cm) produced more grain yield as compared to other intercrops with maize, probably due to the sharing of biologically fixed nitrogen by legumes with maize (Maitra and Ray, 2019). Despite the general trend of reduced maize yield in intercropping scenarios our study highlights the potential for higher total system yields in intercropping compared to monocultures. A similar trend was also observed for stover yield.
 

 
Yield of intercrops
 
The yield of various crops showed variations under different intercropping combinations with rabi maize (Table 2). The highest intercrop yield (196.4 q/ha) was recorded from potato under maize + potato intercropping combination (1:1 row ratio, maize planted at 60 × 25 cm), followed by maize + cabbage (182.3 q/ha) and maize + vegetable pea (85.3 q/ha) intercropping combination. Landschoot et al., (2024), Begam et al., (2024), Li et al., (2023), Talukdar et al., (2022), Sahoo et al., (2024), Singh et al., (2023) and Prakash et al., (2024) also reported the similar results.
 

 
Effect of inter crops on maize equivalent yield
 
In comparison to sole maize, all intercropping combinations produced higher maize equivalent yields. Among the intercrops, the highest maize equivalent yield (241.0 q/ha) was obtained from maize + vegetable pea, followed by the maize + potato intercrop combination (Table 2). However, the lowest maize equivalent yield (166.4 q/ha) was obtained from the maize + cabbage intercropping combination. The higher maize equivalent yield in the maize + vegetable pea intercrop was due to the higher market price of vegetable pea as compared to other intercrops. Maize as a wider-spaced plant offers some crops with intercropping combinations to grow together without economic loss, sacrificing a small maize yield for greater total production in respect of land and time. This practice offered considerable yield advantages and a higher economic return over sole cropping because of its efficient utilization of growth resources (Faruque et al., 1996). This is attributed to more efficient resource utilization and land use (Li et al., 2020). The ’legume effect’, enhancing nitrogen nutrition and reducing weed competition in intercropping systems was evident (Landschoot et al., 2024). Similar results were also reported by Khanum et al., (2019) in maize and cabbage intercropping combinations.
 
Economics
 
Economic analysis is an important tool to evaluate the economic feasibility of intercropping systems. Economic analysis of the various intercropping systems revealed that the gross returns, net returns and B: C ratio was all significantly impacted by the various intercropping systems (Table 2). Compared to the sole crop of maize, every intercrop produced higher gross returns, net returns and B: C ratios. The maize + vegetable pea, maize + potato and maize + cabbage intercropping incurred 156.3%, 128.6% and 93.6% higher gross returns than sole rabi maize, respectively. Among the three intercropping systems, maize and vegetable pea intercropping had the highest gross income (₹ 386098/ha), net return (₹ 322093/ha) and B:C ratio (6.04). This could be attributed mainly to the higher maize equivalent yield with intercropping. Sannagoudar et al., (2021), Singh et al., (2022a), Singh et al., (2022b) and Verma et al., (2021) also reported similar results from maize-based intercropping systems.

Among the intercropping systems, maize + vegetable pea (1:2 row ratio) produced the highest maize equivalent yield and significantly incurred the highest net return, as well as a higher B: C ratio than the rest of the intercropping systems as well as sole crop of rabi maize. Thus, on the basis of two years of findings, it may be concluded that the maize + vegetable pea (1:2 row ratio, maize planted at 60 × 25 cm) intercropping system under irrigated conditions is more remunerative and feasible for the maize growers as compared to the sole rabi maize crop.

The authors declare no conflicts of interest.