In the Ma dagascar highlands, increasing demand for rice combined with increasing land pressure in the lowlands led to the development of upland rice. To tackle the sustainability problem of upland crop production systems, Centre de coopération internationale en recherche agronomique pour le développement ( CIRAD , an internat ional governmental organization ) and TAFA ( an NGO) ha ve developed direct - seeding mulch - based cropping systems (DMC), which not only decrease soil erosion but also increase soil fertility. To understand the mechanisms underlying the performance of upland rice DMC , an experiment was set up in 2003. The yield c omponents of upland rice were studied under high - altitudinal conditions during six rainy season s from 2003 / 04 to 2008 / 09. Treatments compared were two soil management techniques: conventional tillage with removal of most of the crop residues , associated with plowing ( ‘ plo w ing ’ ) ; and a no - till system with direct seeding under mulch made of crop residues ( ‘ no - till ’ ). The rice yields obtained were often better from plo w ing than from no - till, except in the last season. This difference was due to blast disease , which was significantly lower in no - till with low fertilization (best percentage of full grains and better weight of grain). The differences in yields obtained between no - till and plo w ing were mainly explained by problems of crop installation. The plant densities and plant growth were lower in no - till. This was particularly linked to slower root development in no - till. Overall, the biomass production of rotations of rice seemed too low in the highland conditions (low temperature) for the no - till system to be successful in the early years (low soil protection and s lower restructuring of the soil )
Identification of the main constraints for upland rice crop in direct-seeding mulch-based cropping systems under the high altitude conditions of the Madagascar highlands
Influence des conditions pédoclimatiques et de l’itinéraire cultural sur la phase végétative et l’élaboration du rendement de variétés de riz pluvial d’altitude : Recherche d’adaptations spécifiques
Pour que la progression de la production arrive à suivre la croissance démographique, l’extension de la riziculture sur les versants de tanety malgré leur basse fertilité s’impose. Cependant le problème d’érosion et de formation de ravins et de lavaka devient plus qu’un fléau national.