Environmental Engineering Reference
In-Depth Information
Table 11.7 Maize grain yield under slash-and-burn and no-burn
Grain yield (t/ha
1
)
Land-use stage
Field type
Annual cropping
Monocrop maize
Slash, burn, no fertilizer
Monocrop maize
1.9
Slash, burn, with fertilizer
Monocrop maize
3.2
Slash, no-burn, no fertilizer
Monocrop maize
3.9
Slash, no-burn, with fertilizer
Monocrop maize
5.7
Source: GGDP (1992)
Moreover, nutrients applied to the soil in the form of mineral fertilizers are far
less effective on soils in which organic matter has been lost than those which
contain adequate amounts of it. The implication is that if the losses of N, P, and
K were to be replenished by applying 15-15-15 compound fertilizer the
desired effect on crop yield would hardly be attained because of low soil
organic matter content. It has therefore been advocated that soil fertility
replenishment in this region and in Africa in general should aim at integrated
nutrient management (Quansah, 2000; Sanchez
et al
., 1997). This involves the
combined use of organic and inorganic inputs for sustaining soil fertility and
crop yield.
Maize grain yield under slash-and-burn and no-burn
management systems
The results shown in Table 11.7 (GGDP, 1992) amply demonstrate the yield
advantage of no-burn over that of slash-and-burn. Maize grain yield under
no-burning was 51 per cent higher than that under slash-and-burn. No-burning
without mineral fertilizers was even better in grain yield than slash-and-burn
plus fertilizers. It is further shown that applying mineral fertilizers could
significantly enhance the higher grain yield under slash-and-no-burn.
Residual effect of slash-and-burn and no-burn on the yield
of a maize/cassava intercrop
Table 11.8 shows the residual effect of slash-and-burn and mulching on the yield
of a maize/cassava intercrop over a three-year period. The land-use study was
carried out at Nkawie under the same land-use stage and field type as presented
in Tables 11.4 and 11.5.
