Bandarban, a region adorned with picturesque hills in southeastern Bandarban, a region adorned with picturesque hills in southeastern Bangladesh, has been grappling with challenges in agricultural productivity for years. Traditional farming practices and irrigation water scarcity have exacerbated these issues. The hill region has long been accustomed to Jhum cultivation, where farmers first clear the vegetation of a hill, burn it and then cultivate it for a set  period before returning to it after 3-5 years. However, this practice has led to reduced productivity and increased challenges due to population growth and shrinking agricultural land. Moreover, a significant portion of the population has been engaged in tobacco cultivation, a well-known yet perilous practice associated with severe health risks.

The C-SUCSeS Project of SAARC Agriculture Centre aims to provide a comprehensive solution to mitigate and adapt to climate change risks, enhance agricultural productivity, and offer sustainable alternatives to practices like tobacco cultivation. Through this visionary C-SUCSeS project, BARI scientists are working tirelessly to devise a solution that not only mitigates climate change risks but also enhances agricultural productivity and provides sustainable alternatives to tobacco cultivation. The ultimate goal is to establish a resilient agricultural system that adapts to changing climate challenges and uplifts the livelihoods of farming communities in hilly regions.

Intercropping or Companion Cropping as a Climate-Smart Solution:

In the Sultanpur village of Sualok Union in Bandarban, farmers under the facilitation of the On-Farm Research Division (OFRD) of BARI have embraced companion cropping alongside maize on nearly one acre of land. This innovative approach has contributed to a transformative change in local agriculture, providing economic benefits and sustainable alternatives

Maize, a staple crop in the hilly region, is now cultivated in dual seasons—Kharif and Rabi. This dual-season approach has gained popularity due to the growing maize market, particularly for its use in livestock and fish feed. Farmers are increasingly exploring companion cropping as a profitable alternative to traditional practices like tobacco cultivation.

Key Features of the Technology:

·         Adjusting the spacing between Maize rows from the standard 60 cm * 25 cm to 70 cm * 25 cm, resulting in approximately 9500 plants lower per hectare. Although this reduced the maize yield per hectare to about 1.78 tons, the overall system productivity increased by about 18 tons per hectare, leading to a net profit increase of around 150% for farmers.

·         The land was prepared by ploughing and cross-ploughing using recommended fertilizers for maize only. Both maize and companion crops were sown on the same day. Red amaranth, spinach, and chinese cabbage (green) seeds were sown between the two lines of maize, each at a distance of 20 cm, 25 cm, and 25 cm, respectively, using continuous sowing, while a single line of bushbean (a leguminous vegetable) seeds were sown at a distance of 15 cm. Harvesting of all leafy vegetables was done within one month after sowing seeds, and bushbean pods/seeds at two months for market utilization.

·         Top-dressing of urea for the companion crops was done within 2-3 weeks of seed germination. This allowed the companion crops to be ready for sale in the market within the next week. The additional fertilizer also contributed to the robust growth of main cropss. This system yielded approximately 14 tons of leafy vegetables per hectare, with a farmgate price of 30 Taka per kilogram.

Experimental Site and Meteorological Conditions

The experiment was conducted in farmers fields of hill valleys in Bandarban, 2023-2024, during the winter season. The experimental areas were located in the Northern and Eastern Hills area (AEZ-29) of  Bangladesh (FAO/UNDP 1988). The experimental site is categorized as a lower hill and medium slope, with a soil texture of clay loam and a relatively low organic matter content of 2.72%. The pH of the soil is measured at 5.90. In the study area, the dry season is warm and mostly sunny compared to the oppressively hot, harsh, and cloudy wet season. The average annual temperature ranges between 31 ◦C and 12 ◦C during the experiment. The experimental area has a subtropical humid climate characterized by hot and humid summers and cool winters.

Table 1. Soil type and nutrient status of the experimental area in AEZ-29 (Northern and Eastern Hill)

Nutrient Status

N

P

K

S

Zn

B

Ca

Mg

Cu

Fe

Mn

Total%

(µg/g)

(meq/100 g)

(µg/g)

(µg/g)

(µg/g)

(meq/100 g)

(meq/100 g)

(µg/g)

(µg/g)

(µg/g)

0.17

4

0.04

7

0.9

0.45

5.04

3.52

1.4

52

27

Source: SRDI, Bandarban

Treatments and design

The experiment was conducted in a farmer’s field of hill valleys in Bandarban during the rabi season, 2023-2024. Two treatments viz. T1: Sole Maize, T2: Maize+BARI Bushbean-2, T3: Maize+Red amaranth, T4: Maize+Spinach and T5: Maize+chinese cabbage were used for the experiment. It was laid out in randomized complete block design (RCBD) with six dispersed (six farmer’s field) replications. The unit plot size was 12 m × 10 m.

Crop management

Land preparation for all crops began two weeks before seeding in November. This required ploughing, cross-ploughing, and laddering. Before sowing, all seeds were treated with 2 g/L Bavistin to reduce disease-causing organisms on the seed surface. Urea, triple super phosphate (TSP), muriate of potash (MOP), gypsum, zinc sulfate, boric acid, and cow dung were applied at 600, 250, 250, 220, 12, 10 kg and 100 t  ha-1, respectively. All cow dung, TSP, gypsum, zinc sulfate, boric acid, and one-third of MOP were applied during pit preparation (5 days before sowing). The total volume of Urea and the remaining MOP were applied in four equal instalments at 15, 35, 55, and 75 days after seed sowing. At the early vegetative stage, 15 days after sowing, leafy vegetables were top-dressed with 50 kg ha-1 of N. Two times weeding and earthing up were done after each top dress. The crop was irrigated at 20-40-70 DAS and grain filling stage where irrigation water was available. The commercial varieties used for this experiment were Uttaran-2, BARI Bushbean-2, BARI Lalshak-1, Sabuj Chaya, and Rupasi for maize, bushbean, red amaranth, spinach and chinese cabbage respectively. All seeds were sown on the same day (rabi/winter season).  For maize, 70 cm x 25 cm and Bushbean seeds were sown, maintaining 30 cm × 20 cm spacing and seeds for leafy vegetables were sown following the line sowing method. Line-to-line distance for red amaranth, spinach and chinese cabbage, was 20 cm, 25 cm, and 25 cm, respectively. After a week of seedling emergence in each line, leafy vegetable thinning was carried out for healthy growth. Weeds were hand-pulled before top dress and split fertilizer applications. Two irrigations were provided in all crops at 15 and 20 days after sowing (DAS). Chemical protection measures were taken to check different insect pests and disease infestations. The shoot and fruit borers were managed with a sex pheromone trap (Cuelure). Plot-wise data on yield and yield-contributing characters were recorded and converted to tons per hectare. The rest urea was applied as top dress in two equal splits at 8 leaves and tasseling stages. The component crop was harvested within 25-30 days after sowing. At harvest, the yield and yield attributes were compiled and tabulated properly for statistical analysis. Analysis of variance was done in a t-test with the help of the computer package STATISTIX 10. In addition, fuel consumption (L ha-1) and irrigation requirement (No.) were recorded for intercrops and conventional plots.

Results and Discussion

Yield and yield attributes: From the results it is revealed that the yield of Maize was significantly influenced by intercrop combinations. The highest Maize Equivalent yield (31.43 t/ha) was obtained from T5 treatment (Maize+chines cabbage) and the lowest (10.50) from T1 (Sole maize) (Table 2).

Table 2. Yield and yield contributing characters of Maize and vegetables under intercrop combinations at Bandarban during the year of 2023-2024

Treatments

Average Maize yield (t/ha)

Vegetable yield (t/ha)

Maize Equivalent yield (MEY) (t/ha)

T1= Maize as sole

10.50

10.50

T2= Maize+ Bushbean-2

 

12

23

T3= Maize+ Red amaranth

8.72

10.66

21.39

T4= Maize+ Spinach

 

10

20.60

T5= Maize+ chines cabbage

 

22.83

31.43

Unit Price: Maize=25, Bushbean=30, Red amaranth= 30, Spinach=30 and chines cabbage= 25 Tk/kg respectively

Cost return analysis: Cost and return analysis revealed that the highest gross return (785750 Tk. ha-1), net return (695750 Tk. ha-1) and BCR (7.73) was obtained from intercrop combination T5 (Maize+chinese cabbage) over T1 (sole Maize) (262500 Tk. ha-1, 184500 Tk. ha-1 and 2.37 respectively).

Table 3. Equivalent yield and economics of Maize and intercrops at Bandarban during the year of 2023-2024

Treatments

Maize equivalent yield (t ha-1)

Gross return (Tk ha-1)

Total variable cost (Tk ha-1)

Net return (Tk ha-1)

BCR

T1= Maize as sole

10.5

262500

78000

184500

2.37

T2= Maize + Bushbean-2

23

575000

110000

465000

4.23

T3= Maize+ Red amaranth

21.39

534750

90500

444250

4.91

T4= Maize+ Spinach

20.6

515000

90000

425000

4.72

T5= Maize+ chines cabbage

31.43

785750

90000

695750

7.73

Price (Tk. Kg-1): Maize=25, Bushbean=30, Red amaranth= 30, Spinach=30 and chines cabbage= 25 Tk/kg respectively

Irrigation efficiency

It was also observed that the intercropping system required less irrigation water compare to the conventional system (Fig. 2). The average total number of irrigations applied for intercropping was 3 but in the conventional (sole crops) method it was 5. In monocrop system, maize and vegetables required 3 and 2 irrigations respectively. In the intercropping system, 2 irrigations can be saved over conventional practice. This result indicates the intercropping method increases water use efficiency as compared to the sole method.

Fuel consumption for tillage and irrigation

Fuel consumption data is presented in Table 2. The intercropping system had a lower fuel consumption rate (L/ha) than the sole crop system used for its operation. In the context of land cultivation, it was observed that the intercropping method necessitated a fuel consumption rate of 22 liters per hectare, while sole crops required 18 liters of diesel per hectare for land preparation. Similarly, the irrigation requirements, measured in liters per hectare, were found to be 25, and 20 for intercropping, sole vegetables, respectively. The practice of intercropping reduced the amount of fuel needed for operation.

Table 4. Fuel used for tillage and irrigation operation in sole and intercropping system

SL No.

Operations

Sole Maize (L/ha)

Sole Vegetable (L/ha)

Intercropping (L/ha)

1

Tillage

22

18

22

2

Irrigation

25

20

25

Testimonials from Local Farmers: Local farmers, such as Azad Mia and Kishani Sabina Yasmin, highlighted the positive changes brought about by companion cropping, including efficient weed control, increased soil moisture retention, and dream-like yields. This method not only ensures high yields but also facilitates the cultivation of additional crops for family consumption without requiring additional land.

Careful consideration is crucial in managing companion cropping, as highlighted by farmer Anju Mia. Protection of crops from hens and chickens, proper fertilization, and timely watering are essential for maximizing the benefits of this innovative cultivation method. Scientific officer Imam Hossain of OFRD, BARI shares success stories, emphasizing the integration of climate-smart technologies for increased production and profit.

Bandarban is witnessing not just crops but a revolution—a transformation promising economic prosperity for farmers and a sustainable, climate-smart future for agriculture in this challenging terrain. Maize’s companion cropping emerges as a symbol of innovation, resilience, and progress in the heart of Bangladesh’s hilly landscapes. The success stories from Sultanpur village reflect the potential of this approach to redefine winter vegetable cultivation, setting the stage for a brighter and greener future for the region’s agriculture. The adoption of intercropping technology, driven by the C-SUCSeS Project, stands as a beacon of hope, showcasing the power of sustainable agricultural practices to overcome challenges and usher in a new era of prosperity in Bandarban.

Authors:

1.   Mohammad Tanharul Islam, Senior Scientific Officer (A.C.), On-Farm Research Division, Bangladesh Agricultural Research Institute (BARI)

2.      Mr. Kinzang Gyeltshen, Regional Programme Coordinator, C-SUCSeS Project, SAARC Agriculture       Centre

3.      Md. Kabir Hossain, Knowledge Management Consultant, C-SUCSeS Project, SAARC Agriculture       Centre

4.      Dr. Apurbo Kumar Chaki, Senior Scientific Officer, OFRD, BARI & Associate National Focal Point, C-SUCSeS Project (Bangladesh component)

5.      Dr. Md. Mazharul Anwar, Chief Scientific Officer, OFRD, BARI & National Focal Point, C-SUCSeS Project (Bangladesh component)