The influence of soil moisture on maize growth and yield in flood recession farming in the Okavango Delta: the case of maize

Flood recession farming (locally known as molapo farming) is a farming system which is based on natural irrigation and fertilization of the floodplain where crops are cultivated on the remaining soil moisture of the receding flood. Maize (Zea mays) is the most commonly grown crop in molapo farms and yet the contribution of the moisture regime in meeting the crop’s water requirements is poorly understood. In particular the link between residual moisture and moisture supplied by rainfall and its effect on maize growth has not been investigated. This study investigated this aspect at three sites (Tubu, Xobe and Shorobe) located in the Okavango Delta, Botswana where molapo farming is mainly practiced by small-holder farmers. These small-holder farmers are faced with challenges such as high or low floods and fields vulnerable to livestock grazing leading to early harvesting. The study established that main implications for the farming community were that planting too close to the channels may be too wet or waterlogged while moving away from the channel can become too dry leading to poor plant emergence and low yields.