58
Reduction in rainfall by about 50% shows substantial reductions in both grain
and stover yields. Both stover and grain yields continue to increase as rainfall
increases, however, the increases are very small.
5.3.3 Combined Effects of Climate Factors on Maize
We evaluated the combined effects of climate elements on maize grain and stover
yield. Hot/wet and hot/dry climate scenarios for both RCP4.5 and 8.5 were used.
The effects were simulated by both the APSIM and DSSAT model on three soil
types. The two models show divergent effects of combined climate elements on
both maize grain and stover. The APSIM model shows more stover yield reductions
while the DSSAT model shows more grain reductions across soils and climate scenarios. Yield reductions are more pronounced on better soils than on the other two
soil types, while the hot/wet climate scenario shows more positive effects than the
hot/dry scenario. Climate effects are more distinct for grain than for stover and this
is more pronounced for RCP8.5 than RCP4.5. Generally, the hot/dry conditions
show substantial reductions with probability of 35, 40 and 70% of getting reduced
grain yields as simulated by the APSIM model while the DSSAT model shows 85,
75 and 85% on poor, average and better soils respectively under RCP4.5 hot/dry
conditions. Generally, maize production will decrease under future climate scenarios though the degree of impact differs among soil types.
5.3.4 Combined Effects of Climate Factors on Groundnuts
In contrast to maize, groundnuts mostly showed positive effects with yield increases
of more than 50% for stover in some instances. The APSIM model generally simulated positive grain yields under RCP4.5 and reductions at a probability of 19, 30
and 50% for poor, average and better soils, respectively under RCP8.5 hot/dry conditions. Stover yields showed positive yield increases for both RCP4.5 and RCP8.5
under hot/wet conditions. However, reductions were simulated for hot/dry conditions mainly for RCP8.5. The DSSAT model shows more negative effects on grain
yields than stover yields across soil types and climate scenarios. Grain yield reductions are more pronounced for average and better soils under hot/dry climate scenarios for both RCP4.5 and 8.5. Stover yields on average soil are mostly affected
showing about 40% probability of getting negative yields. Although groundnuts
seem to be benefitting on average, however there are years when yield changes are
negative.
P. Masikati et al.
Reduction in rainfall by about 50% shows substantial reductions in both grain
and stover yields. Both stover and grain yields continue to increase as rainfall
increases, however, the increases are very small.
5.3.3 Combined Effects of Climate Factors on Maize
We evaluated the combined effects of climate elements on maize grain and stover
yield. Hot/wet and hot/dry climate scenarios for both RCP4.5 and 8.5 were used.
The effects were simulated by both the APSIM and DSSAT model on three soil
types. The two models show divergent effects of combined climate elements on
both maize grain and stover. The APSIM model shows more stover yield reductions
while the DSSAT model shows more grain reductions across soils and climate scenarios. Yield reductions are more pronounced on better soils than on the other two
soil types, while the hot/wet climate scenario shows more positive effects than the
hot/dry scenario. Climate effects are more distinct for grain than for stover and this
is more pronounced for RCP8.5 than RCP4.5. Generally, the hot/dry conditions
show substantial reductions with probability of 35, 40 and 70% of getting reduced
grain yields as simulated by the APSIM model while the DSSAT model shows 85,
75 and 85% on poor, average and better soils respectively under RCP4.5 hot/dry
conditions. Generally, maize production will decrease under future climate scenarios though the degree of impact differs among soil types.
5.3.4 Combined Effects of Climate Factors on Groundnuts
In contrast to maize, groundnuts mostly showed positive effects with yield increases
of more than 50% for stover in some instances. The APSIM model generally simulated positive grain yields under RCP4.5 and reductions at a probability of 19, 30
and 50% for poor, average and better soils, respectively under RCP8.5 hot/dry conditions. Stover yields showed positive yield increases for both RCP4.5 and RCP8.5
under hot/wet conditions. However, reductions were simulated for hot/dry conditions mainly for RCP8.5. The DSSAT model shows more negative effects on grain
yields than stover yields across soil types and climate scenarios. Grain yield reductions are more pronounced for average and better soils under hot/dry climate scenarios for both RCP4.5 and 8.5. Stover yields on average soil are mostly affected
showing about 40% probability of getting negative yields. Although groundnuts
seem to be benefitting on average, however there are years when yield changes are
negative.
P. Masikati et al.