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to maintain soil fertility for regional crop production.

However, owing to the recent population increase (more

than 3 per cent annually), together with failure of the

corralling system and shortened fallow period, soil fertil-

ity cannot be well sustained by these local practices and the

degradation of land productivity has resulted. Aiming at the

improvement of soil fertility and expansion of crop produc-

tion in the region, JIRCAS commenced a project based at

Niamey, Niger, in collaboration with the International

Crops Research Institute for the Semi-Arid Tropics and the

National Agricultural Research Institute of Niger in 2003.

The goal was to develop technology options through inves-

tigating more efficient use of plant resources, considering

the biological and physical functions of fallow plants and

lands, and incorporating well-adapted leguminous crops

into the cropping systems. The developed technology

options were evaluated for adoption by local farmers in

on-farm participatory trials.

The project focused on wind-blown materials and their

fates, as wind erosion is a major cause of the loss of rela-

tively fertile surface soils/sediments in the Sahel. A new

agricultural practice, called the Fallow Band System, was

proposed and verified for the maintenance of soil fertility

in the field.

Five-metre wide fallow bands were arranged at

a right angle to the direction of erosive storms (east wind)

in a cultivated field during the rainy season. Fallow bands

can be easily created by skipping the usual seeding and

weeding. Pearl millet plants, a staple food in the Sahel,

were cultivated in other areas of the field in a conven-

tional way. The fallow bands were also maintained in the

next dry season, so they are expected to catch wind-blown

materials containing a lot of nutrients. In the next rainy

season, new fallow bands were made aside from the former

bands towards the direction of the wind. Crops were culti-

vated on the previous fallow bands as well as in other

areas of continuous cultivation. The pearl millet yield was

estimated to be increased by 36 per cent to 81 per cent,

compared with the area where the fallow band system was

not applied. Also, wind erosion was reduced by about 70

per cent on a whole-field basis. This ‘no labour, no cost’

practice has been rapidly disseminated to farmers in the

Sahel through local communities in follow-up activities by

the Japan International Cooperation Agency.

We have also studied ways to improve the quality of the

fallow band, by enhancing native fallow plants which can

fix more nitrogen from the air through biological nitrogen

fixation — for instance, a promising annual leguminous

Cassia mimosoides.

JIRCAS is also currently conducting research activities in

the savannah of West Africa (Ghana and Burkina Faso), on

applicable technology options of conservation agriculture to

minimize arable land degradation and to enhance soil fertility.

Outline and features of the Fallow Band System

Source: Courtesy of the Ministry of Agriculture, Forestry and Fisheries, Japan

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