Conclusions

This study has investigated the effect of ENSO on seasonal rainfall amounts at nine farming sites in Ghana. Out of six sites in the south, there was a strong ENSO influence on seasonal rainfall at three sites namely Axim, Akatsi and Kpandu. In the middle

Table 20.2. Mean simulated maize yields (kg ha *) and percent yield increases as a function of ENSO phase and planting date

ENSO phase

N-fertilization rate (kg N ha"1)

Planting date (PD)/yield increase

(%)

(%)

(%)

El Niño

0

702.4

-

731.7

-

744.9a

-

60

2848.7

305.6

2142.3

192.8

2696.1

262.0

120

2940.3

3.2

2696.4

25.9

3265.3

21.1

La Niña

0

682.2

-

676.8

-

540.6

-

60

3307.8

384.9

2331.8

244.5

2030.4

275.6

120

4038.6

22.1

3510.0

50.5

3575.0

76.1

Neutral

0

682.7

-

768.9

-

662.2

-

60

3192.5

367.7

2 790.3

262.9

2555.8

286.0

120

3 938.7

23.4

4003.4

43.5

4107.8

60.7

8 Highest maize yields with respect to planting date in boldface.

8 Highest maize yields with respect to planting date in boldface.

belt, ENSO influence was weak as observed for Kumasi. Seasonal rainfall at one out of the two northern sites (Yendi) showed strong ENSO dependence while at Wa, ENSO influence was not significant.

Simulation of peanut and maize under varying ENSO phases and planting dates showed that the intermediate planting date was best for Kpedevi irrespective of the ENSO phase. Under El Niño and La Niña early planting date was best for Goronga while the intermediate planting date was the preferred date under neutral conditions. The study suggests that ENSO-based seasonal forecast could be beneficial to agricultural planning at the farming zones considered.

Acknowledgements

START and the Packard Foundation, USA, financially supported this study. We are most grateful for their financial assistance.

References

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