“Is inorganic fertilizer the best initial ‘entry point’ for an integrated soil fertility mgmt approach? If so what should a programme look like bearing in mind past failures? If not, what should be done first?”
The best entry point is fertiliser (organic/inorganic) COUPLED with improved water mgmt at field scale. Multiple approaches (technologies) are available, and no single solution can be used as blanket for the wide variety of farmers ….. The COUPLING of fertiliser with water is more essential the drier the agro-climatic conditions. Water mgmt alone will not diminish the current yield gaps on in-fertile soils with low input/low re-circulation of organic matter. Equally, the full benefit of fertiliser (organic/in organic) inputs will not be realised without addressing water limitations by recurring dry spells and possibly droughts in semiarid and sub humid climatic zones.
Multiple benefits of increased re-circulation of OM in a crop system will not be sequestered if C/N quota isn’t favourable: Thus, the input of (inorganic) N may be a essential component to increase yields, as it enables a favourable C/N, increase overall biomass, and enables re-circulation of OM back to soils putting a cropping system on positive soil health trajectory.
It is not a matter of doing water or fertiliser ‘first’: With current available knowledge, the important issue is how to effectively provide knowledge input linking at first water and nutrient management packages, but also soon the use of improved varieties. Only the coupling can achieve substantial yield increases over relatively short time (possibly 5-10 years with effective knowledge/awareness spread??).
To my mind (not with any solid evidence that it works of course)
- subsidised fertiliser, specifically targeting macro as well as micro nutrients in the area of distribution: subsidising fertiliser have had fast & positive response in Malawi , partly due to favourable rains enabling the positive response of fertiliser input (any other evidence at national scale in recent times in SSA?)
- strong emphasis on fertiliser distribution coupled with water management small and large scale investments
- development and distribution of improved seeds to further boost investment gains in water & fertilizer (evidence??)
- the current trend of privatising extension service will most likely not help promote technological sound packages in soil-water-crop mgmt that are diverse enough to address smallholder farmers knowledge gaps. Privatising rural extension service may be more beneficial to specific farmers, and more promote specific use of crops and agro-inputs not necessarily managing negative environmental (and social) externalities very well… It will also only be affordable to certain income strata (evidence?)
‘How should success and impact be defined?’
Raising the yields, i.e. realising the potential with better water and nutrient management will have environmental impacts as well as social. There are no longer any space that are not utilised or provides produce and services necessary for humans and society. Any agricultural development, whether intensifying existing systems through nutrients and water, seeds etc, or expansion will have effects on surrounding landscape. Some of these are positive, and some can be negative. The ‘next’ /first? / ‘triple/ green revolution in Africa must be continuously evaluated for social as well as environmental impact. It cannot be acceptable that the negative environmental (and perhaps social??) impacts of the green revolution in Asia are reproduced. It would create extremely costly avenues to re-tract such negative effects of agricultural development, which can be ill-afforded both from economic (Africa by and large strapped for cash) as well as climate adaptation perspectives (measures in agriculture development needs to be climate change ‘proofed’ to avoid future costs & livelihood losses).
There is globally, and occasionally regional and nationally, awareness, and willingness to consider pro-active measures to avoid negative externalities. However, such measures usually tend to add cost without adding visible (economic) value in short term…
Example: when smallholder farmers in a given area adopted conservation tillage (as desirable), there was a tendency to put more land into production, i.e. area expansion of agriculture, which globally can be ill afforded, although feasible locally.
Example: the use of treadle pumps have at local spots been popular & provided users with much needed cash income, further investment in agriculture production and development opportunities as well as achieved absolute poverty alleviation. However, non-monitored water level has tended to decrease altering downstream seasonality of flows and user opportunities…
Clearly, success and impact are not solely about short term yield increases, not even about poverty alleviation per se. Both these obvious criteria need to be integrated with long term measures of environmental and social sustainability: negotiating tradeoffs, building resilient systems which can cope better with change/stress, whether climatic, economic or other,. It is crucial in agro-development that the resource base (of which we have comparatively good basic knowledge ) is maintained and not ‘mined’ whether it refers to land area, soil nutrient, or water management…Thus it is necessary that agro-development is environmentally and socially monitored and evaluated to ensure development takes a desired route, and avoid undermining negative externalities (social and environmental) in the near and far future
Jennie Barron, Research fellow in water management
Stockholm Environment Institute/SEI