Andaman Islands have limited land resources, with multiple soil problems. Transportation of perishable commodities is difficult and unaffordable. Hence, perishables are needed to be produced locally. Production of vegetables, fruits and flowers poses the following serious problems in these remote islands:
Possibility of growing perishable horticultural crops in a limited coastal plain area is limited due to continuous high intensity and heavy rainfall spreading over eight months of the year.
Land availability with good sunshine on hills is highly restricted as most area is occupied by multi-storeyed cropping systems of coconut, areca nut and other crops and most other area under reserve forests
Available area is severely infested with giant African snails which devastate succulent crops of fruits, vegetables and ornamental crops.
Being nocturnal in habit, and under heavy rainfall, control of these snails is a practical impossibility without causing serious environmental damage
The soils are infested with wilt causing bacterial pathogens and hence most crops are prone to bacterial wilts on these soils. Many crops do not have wilt resistant varieties
One of the possible solutions to this is to manipulate rice fields to suit vegetable cultivation during the main rice season. The broad bed and furrow (BBF) developed by CIARI is a technique for growing vegetables, flowers and fodder in the midst of rice fields throughout the year. While rice and vegetables and fodder are grown in the rainy season, the system also manages salinity and harvesting water in furrows for dry season vegetable production. The system offers a natural control of African snails as they do not move towards standing water for the fear of salinity of the water seen at times during high tides.
Making of BBF
The BBF is made by a cut-and-fill method. A six-feet width along the length of the rice field is cut and filled in a four-feet adjacent area in the same field. The area so-filled is raised and levelled in an inverted trapezium shape. The edge of the trapezium is stabilized by planting Napier grass. The furrow area is also levelled and a green manure crop is sown, grown for 45 days and incorporated. The raised-bed portion is limited to a required level so that bacterial-wilt causing organisms are brought to a manageable level. Several such inverted-trapezium shaped land-forms are made in the required rice fields in continuity, as shown in the figure below:
Schematic diagram of BBF showing inverted-trapezium shaped land-forms
This system provides drainage for vegetables on the beds and standing water for rice-cum-fish in the furrow. The raised portion of four feet width is used for cultivating vegetables, if any. The furrow is used for rice cultivation. The field stabilizes in one season. The BBF system permits fish-rearing in furrows and fodder crops on the beds, both of which help include animal components in the new system.
Physical and ecological advantages of the technology
Soil erosion is minimal as soil, if any, lost from the bed portion is retained in the furrow
Nutrients leached from the bed portion are utilized by fodder growing on the edges, and by rice in the furrow
Absolute control of the African snail without use of any chemical,by virtue of exploiting their behaviour
Bacterial-wilt disease is brought under control by liming and use of soil-borne, disease-suppressing biofertilizers
100% sunshine is provided to crops, unlike very restricted sunlight on the hills
Nutrient use efficiency and productivity is higher
Water management becomes easier
The present cropping intensity of 100% to 125% in the rice area can be increased to 300% in beds and 200% in furrows by adopting the BBF land manipulation
It helps farmers effectively and efficiently utilize their resources for profit-maximization
Adoption of Broad-Bed and Furrow (BBF) system provides an opportunity for crop diversification in low-lying paddy lands; Higher net return can be realized by growing vegetables, flowers and fodder
The system of BBF has all the ecological, economical and social features to qualify for a sustainable soil-management module.
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