Effects of Water Management on the Performance of NERICA 4 in Semi-Arid Areas, Tanzania

Publication Type

Contribution to conference

Authors

Schappert, A., Schaffert, A., Germer, J., Asch, F.

Year of publication

2016

Published in

Solidarity in a competing world - fair use of resources

Conference name

Tropentag

Conference location

Vienna

In semi-arid areas in Africa soil degradation and droughts are reducing agriculturalproductivity. In order to counteract the yield reduction soil and water conservation methodsneed to be applied. The aim of this study is to analyse the potential of growing upland rice,one of the most important stable crops, in seasonal drought prone areas in Tanzania. Threewater management techniques are identified and evaluated: modifying the soil surface tocollect and save water, adding a minimum amount of water in case of drought events andto decrease evaporation by adapted weeding management.Experiments were conducted near Dodoma, Tanzania during the wet season from Janu-ary until May in which an average precipitation of 430 mm is recorded. The upland ricevariety NERICA 4, which is well adapted to the African environment, was used for inve-stigating the potential for growing NERICA 4 upland rice under following managementpractices: i) rainfed, ii) rainfed in combination with tied-ridging, iii) tied-ridging with ad-ditional irrigation to keep soil moisture above the permanent wilting point of the soil (lifesaving irrigation), iv) life saving irrigation without tied ridges and v) under irrigation (fullcrop water requirements). Those options were combined with time based weeding strate-gies. This study explores the effects of these water management methods on the soil waterstatus and the performance of the crop in terms of leaf area, specific leaf area (SLA),biomasspartitioning, yield determining components like number of productive tillers andspikelets, grain yield, harvest index (HI), yield loss and water use efficiency (WUE) wereinvestigated. Tied ridges did not improve irrigated cropping systems. The competitivenessof weeds led to changed soil moisture values and microclimate within the canopy, causeddevelopment delay and reduced grain yields up to 45 %. The poor rainfall distribution inthe growing season 2015 provoked total crop failure of all rainfed treatments without irri-gation and caused yield loss and thus low water use efficiencies for the treatments with lifesaving irrigation. In that context possibilities for growing upland rice successfully underrainfall limited conditions will be discussed.