Author Description

Because of the high sensitivity of plants to soil chemical characteristics, water management which determines redox conditions and Fe and Al concentrations, is a key to the cultivation on acid sulphate soils. Unfortunately, the very high soil permeability makes water control very difficult, especially in the years immediately following reclamation. This makes it difficult to maintain good cropping conditions through irrigation or drainage. Consequently, the time window during which optimal cropping conditions are met is very short. Its starting date and duration are also spatially variable, in relation to microtopography. To extend this time window, farmers in the Plain of Reeds start cultivation as soon as possible, broadcasting pregerminated rice seeds in flood water, before it has completely receded. In these cropping conditions, farmer-managed trials were conducted for four years, after precise site characterisation (using geostatistical methods). Detailed studies of crop phenology and yield led to the development of a semi-quantitative model of rice yield build-up. Yield is mainly determined by panicle density and plant growth, reflected in the weight of one grain.