Grain Legumes and Green Manures for Soil Fertility in ... - cimmyt
Grain Legumes and Green Manures for Soil Fertility in ... - cimmyt
Grain Legumes and Green Manures for Soil Fertility in ... - cimmyt
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management operations, such as<br />
crop rotation, mulch<strong>in</strong>g, livestock<br />
:,; movements or manure transfer.<br />
Transfers will be possible between<br />
fields with<strong>in</strong> one farm, between<br />
farms, <strong>and</strong> between the farms <strong>and</strong><br />
rangel<strong>and</strong>. Different methods <strong>for</strong><br />
comb<strong>in</strong><strong>in</strong>g labour <strong>and</strong> crop /<br />
livestock models are be<strong>in</strong>g<br />
considered; one idea is <strong>for</strong><br />
management activities to be made<br />
cont<strong>in</strong>gent on there be<strong>in</strong>g sufficient<br />
available labour. The modular<br />
structure will allow different<br />
versions of submodels to be<br />
swapped <strong>in</strong> or out depend<strong>in</strong>g on<br />
the detail required.<br />
Figure 1. Resource flows with<strong>in</strong> <strong>and</strong> between heterogeneous farms<br />
complexity are however available <strong>for</strong> different<br />
flows, <strong>and</strong> ideally an appropriately complex model<br />
can be chosen <strong>for</strong> each part of the system <strong>and</strong> l<strong>in</strong>ked<br />
together where necessary to allow an <strong>in</strong>tegral<br />
analysis.<br />
A software framework (Figure 2) is be<strong>in</strong>g developed<br />
to <strong>in</strong>tegrate exist<strong>in</strong>g crop, soiC livestock <strong>and</strong><br />
bioeconomic models <strong>in</strong>to a model of the whole<br />
system. This <strong>in</strong>tegrated model will be used to<br />
explore nutrient use efficiency <strong>and</strong> labour<br />
productivity, <strong>and</strong> tradeoffs between short <strong>and</strong> long<br />
term contributions to soil fertility, <strong>in</strong> Afric\U1<br />
farm<strong>in</strong>g systems.<br />
The NUANCES framework will allow the<br />
simulation of spatially <strong>and</strong> temporally complex<br />
The aim is to create a model that can<br />
assist <strong>in</strong> <strong>in</strong>tegrat<strong>in</strong>g the expert<br />
knowledge of farmers <strong>and</strong> of scientists from<br />
different discipl<strong>in</strong>es. The modular structure will<br />
allow the pr<strong>in</strong>ciple of 'just-sufficient-complexity' to<br />
be upheld, s<strong>in</strong>ce simple models can be used <strong>for</strong><br />
whichever processes are peripheral to the parts of<br />
the system be<strong>in</strong>g considered. As well as provid<strong>in</strong>g a<br />
framework <strong>for</strong> iterative experimentation <strong>and</strong><br />
modell<strong>in</strong>g, the model will shed light on which<br />
processes most affect costs <strong>and</strong> benefits <strong>and</strong> thus<br />
allow recommendations to be better targeted.<br />
NUANCES will lead to the iterative <strong>and</strong><br />
collaborative design of more productive, susta<strong>in</strong>able<br />
systems, l<strong>in</strong>k<strong>in</strong>g directly to policy at local artd<br />
greater scales, <strong>and</strong> will facilitate the development of<br />
further rules-of-thumb <strong>for</strong> farmers.<br />
Farm (x J ",~arm rtln~')<br />
LV Uves(Qck<br />
(x 3 sizes· callie,<br />
sh""p+go.~,<br />
poUltry)<br />
P'L f<strong>in</strong>ance<br />
<strong>and</strong> Labour<br />
L T L<strong>and</strong> TyP