Keywords :

DMCs and geographical extension of conventional cropland areas into dry humid tropical regions

The geographical range within which crops are conventionally grown should be extended into soil-climate areas under harsher conditions so as to be able to produce more and better while meeting the new market demand. Three complementary ecosystem functions that occur under DMC are essential. First, enhanced water resource management, by reducing runoff and evaporation. Second, improving the physical, chemical and biological fertility of soils through biological-organic means is possible at low cost. Finally, DMCs enable agronomic pest management by promoting natural control. This joint research unit and partners are testing DMCs in two different zones, the Sudano–Sahelian zone affected by chronic rainfall deficits and highly degraded soils, and the humid tropical zone where rainfall is excessive and fragile ferrallitic soils prevail. DMCs have thus enabled the introduction of species that cannot be grown under conventional agricultural systems. In northern Cameroon, under uncertain rainfall conditions and in degraded and hardpan ferruginous soils, conventional millet, sorghum and cowpea based cropping systems can now be enhanced under DMC through the introduction of high-value crops such as rainfed rice (versatile Sebota varieties) and maize. In humid tropical areas where rainfall is often excessive and access to crop plots is generally very limited, intensive cotton cropping (3700-5000 kg/ha of seed cotton) is now possible in rotations with soybean, maize, rainfed rice and grazing crops. DMCs are therefore effective systems for ‘buffering’ harsh climatic conditions. They pave the way for broadening the geographical range of crops with greater requirements with respect to water supply, pest and disease protection and soil fertility. They thus represent an effective operational response to climate change, soil restoration and changing domestic and global market demand.

Eleusine coracana and crotalaria on highly degraded gravelly and hardpan soil in the Sudano-Sahelian region of northern Cameroon " border="0" align="left">