Sandbar Cropping - Simple & Easy farming on sandy soils

 

PUMPKIN GROWING USING SANDBAR

This brief describes a way of growing crops on the sandbars, created by river deposits in Bangladesh, can be done to increase crop production for marginalized farmers.

Introduction

Every year millions of people are affected by sudden shifts in river courses that destroy their crops, farms and homesteads. The sandbars that emerge each year as the rivers recede are not stable enough to support natural vegetative growth and remain as barren sand until the rivers rise again.

These sandbars can be made productive by growing pumpkins and other crops using the pit cultivation approach (by digging small pits and lining these pits with compost).

Accessing these sandbars for cropping can help landless families diversify their incomes, help them overcome seasonal food shortages and facilitate a process of asset building alongside reducing the risks which threaten their livelihoods.

What is sandbar cropping?

The areas, which are vulnerable to erosion, consist of the long river banks, char land (relatively stable places made up from the deposit of sand and soil on the river bed or on top of fertile land due to seasonal flooding over a period of time) and sandbars. Sandbars are large, temporary, barren lands made of the sand and silt deposited as the rivers flood and subsides as well as when they change their course.

Figure 1: Farmer at the Practical Action project site, Gaibandha district, Bangladesh. Photo credit: Practical Action Bangladesh.

In the rivers of the northern areas of Bangladesh, sandbars appear in the dry season (mid- November to Mid-April) due to a decrease in water flow. These sandbars disappear again in the wet season (Mid-April to Mid-October). Most of the sandbars remain underutilized as they are mainly composed of sand; there are thin layers of silt in some areas of the sandbars which are used for cultivation. There are three broad categories of the sandbars: sandbars with sufficient silt cover that have sandy loom soil characteristics and retain moisture for longer periods. Sandbars with no silt cover that are not suitable for production and remain underutilized. Upstream sandbars that emerge in the North during the dry season are different from the sandbars that emerge

downstream in the South. Sandbars in the north are dried parts of the river bed and are prone to erosion whereas the sandbars in the southern part of Bangladesh are less likely to erode and are permanent in nature.

The sandbar cropping technique opens up these otherwise unproductive lands and is ideally suited to adoption by very poor, often landless households.

Growing pumpkins using sandbar cropping

The season for pumpkin cultivation normally starts in October-November. After finding a suitable site, a pit is dug into the sandbar, approximately 1 meter deep and 1 meter in diameter. Pits are usually dug around two meters from each other. Pits are lined with compost which is a mixture of cow dung, soil and water. Jute sacks can be used in extreme geo locations where the ground is very poor (Figure 2). After a few days, seeds are placed into the pit. The compost pits are carefully monitored over the next five months while periodical nursing and irrigation are required.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2: Pumpkin growing using sandbar cropping technique.Illustration: Neil Noble / Practical Action.

Large scale irrigation is not always necessary as the sandbars are usually close to the river and watering can be done by hand. In the initial stages, surface water is used for irrigation. (Where a source is available. e.g. water channels that are created as the river recedes. These water channels disappear in the dry season). Ground water can be used for irrigation when the surface water dries out. Pumpkin fields can be irrigated using a pump and borehole. A low- cost reservoir made with polyethylene sheet can be used for optimize water use. Water is pumped from the borehole to the reservoir through polyethylene pipe/hosepipe and farmers then use buckets to take water from the reservoir to water the individual pits. The quantity and frequency of irrigation depends on the type of soil and season (end stage of the production benefited by rain water).

Figure 3: Pumpkins growing on sandbar (communal) land. Early in the season showing young plants emerging from planting holes. Photo credit: Practical Action Bangladesh.

The ripe pumpkins are often stored in the home, on high platforms that are made of bamboo. The pumpkins produced on the sandbars can be stored for over a year and can assist poor households with both income generation and food security.