How are enhancement prospects affected by availability of natural fertilisers?
Fertilisation is an enhancement that has been put to good use most notably in China. Elsewhere, there will be more and more interest in fertilisation in situations where high stocking rates alone are unable to produce greater yields because the full natural productive capacity of the aquatic system is already being realised. An obvious question then is “Where are there prospects for fertilisation of small water bodies using crop by-products and manures as inputs and also where is continuous growth of Nile tilapia possible?”. The available surrogate for agriculture by-products is cultivation intensity (Fig. 23) and that for production of animal manures is the production of methane from animals (Fig. 24). These have been combined to show the distribution of natural fertiliser inputs for small water bodies (Fig. 25). Figure 23. Cultivation intensity interpreted as availability of agriculture by-products as fertilisers.
