Introduction

• Riverbed farming is the technology can be used to increase household income and to improve the food security of landless and land-poor households in the Terai area of Nepal
• After the river water recedes in the post-monsoon season, vegetables are planted in ditches dug into the seasonal sand banks; the crops are harvested before the onset of the next monsoon
• Seasonally dry riverbeds are an under-utilized resource that can be used for sustainable vegetable production
• In the Indian subcontinent, climate change- induced floods and the encroachment of riverbeds are silting over arable land and increasing the area of sandy riverbeds
• Dry season riverbed vegetable farming was introduced in the Terai by migrants from India
• Unable to access arable land for agricultural production, these landless farmers cultivated the riverbeds, which run dry after the monsoon season, from November to May
• Major riverbed crops are pumpkin, bottle and bitter gourds, cucumber, and watermelon
• This practice dates back to thirty years when mostly Indian nomadic farmers living near the border areas used to come to cultivate the riverbeds which were arable for certain types of crops
• Watermelon was the only crops cultivated in the beginning
• It is estimated that about 78,000 ha of land would be suitable for agriculture cultivation in 21 districts of the country
• Today, river bed farming is practiced in 15 districts, cultivating an area of 1,707 ha only with the involvement of over 10,000 households
• This land availability, if combined with efficient technological advancement in the cultivation practices, can contribute to natural resource management (minerals, water, ecology, forest biodiversity and changing climate) and better disaster management
• In the Terai of Nepal, landless, land-poor, and severely flood-affected farmers lease the riverbeds for cultivation in the post-monsoon dry season (November to May)
• Cucurbitaceae (gourd) vegetables are produced for household consumption and market sale
• By utilizing an under-exploited resource and enhancing farmers’ production skills on marginal soils, leasehold riverbed vegetable farming increases marginal farmers’ options for sustainably coping with the effects of climate change
• Suitable locations for riverbed farming are usually located not more than 30 minutes on foot away from the village
• The riverbed’s sand should have a fine and small- grained texture
• A groundwater table of less than 1 meter depth obviates the need for irrigation, however, both riverbeds and riverbanks may be cultivated
• Riverbeds usually do not require irrigation after crop flowering, but bear higher risks of total crop loss due to environmental shocks such as floods
• Riverbank cultivation decreases the risk of crop loss because of flash floods, but increases labor requirements by necessitating irrigation during the entire season
• Farmers choose either the pit or the ditch system when planting, depending on personal preferences and labor availability
• For the pit system, pits are dug 1 m deep and 0.5 m apart and planted with multiple seeds, the weakest of which are thinned out
• In the ditch system, a trench 1 m deep is dug along the row, with 2 m (cucumber, bitter gourd) to 3 m (watermelon, bottle gourd, pumpkin) space between rows
• Seeds are planted spaced 0.5 m (cucumber, bitter gourd) to 1 m (watermelon, bottle gourd, pumpkin) apart in the ditch
• Irrigation is necessary for seedlings every 2 to 3 days if the soil does not contain enough moisture
• However, if plants have groundwater within 1 m depth, no further irrigation is necessary after this
• Mulching is used to conserve soil moisture, support branch distribution, protect from wind damage, and minimize weed growth
• No tillage is necessary
• Top-dressing or side-dressings are applied at a rate of 15 tons of farmyard manure, 22 kg of urea, 49 kg of DAP, and 22 kg of potash per hectare
• Initial investment costs include the cost of the lease and inputs (seeds, fertilizer) for one season
• Riverbed farming does not require irrigation, tillage, or energy inputs besides human labor, and generates zero waste that is not recycled on-farm.
• As smallholders generally use their resources as efficiently as possible, riverbed farmers use minimal amounts of chemical fertilizers and pesticides as they seek to lower production costs