The Food and Agriculture Organization (FAO) defined that the suitability is a function of crop climate requirements and land characteristics and it is a measure of how will the qualities of land unit matches the requirements of a particular form of land use. The aim of this research is to improve maize production in the lowlands of Lesotho, this is one of the agro-ecological zones with the most arable land and good soils so it is best to determine the suitability of each crop across this region. This will be achieved by quantitatively and qualitatively looking at the climate conditions required by maize and also looking at the physio-chemical soil properties that suffices for the maximum production of the crop.
Climatic potential of maize under dryland farming in the lowlands of Lesotho was investigated using five climatic suitability indices namely: probability of receiving heat units of greater than 1320GDD, probability of a frost-free growing season, probability of seasonal rainfall of more than 650mm and the slope of an area. Also the physio-chemical properties of the soils found in the area of study were investigated looking at 6 soil parameters (pH, porosity, permeability, infiltration, organic matter, moisture equivalence) which are crucial to maize growth. For each of the above parameters a coverage layer was prepared in GIS environment and the layers were overlaid to obtain the agro-climatic suitability map of maize in the lowlands of Lesotho. Weighted overlay method is used for suitability analysis. The spatial analysis show that suitable soils are distributed throughout the whole lowlands but they are highly concentrated in the middle parts of the lowlands and with water requirement, the north-most part of the lowlands is highly suitable while the central part is moderately suitable.
The overall maize suitability in the lowlands of Lesotho indicate that 45.7% of the area is moderately suitable and this are concentrated in the middle to northern lowlands. 49.3% of the lowlands are found to be suitable for maize growth and are distributed throughout the whole lowlands but with the highest concentration in the north-most parts. Of the 5% remaining only 4.3% is highly suitable and it some area in the central part of Maseru near Moshoeshoe-I station.
Future projections show that there will be an improvement of growing degree days across the whole lowlands due to an increase in temperature but as of water requirement satisfaction there is a notable change of reduction especially in Mafeteng and Moshoeshoe-I this is due to reduction in annual accumulated rainfall, this is the case for both two (RCP 4.5, RCP 4.5) scenarios undertaken in this study.
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