Smallholder Farmers, Fertilizers, and Increased Food Demand - Soil Management of Smallholder Agriculture - page 52

by the farmer in the form of external nutrient inputs. ISFM is an important compo-
nent of efforts to restore soil fertility. Central to ISFM strategies is the combined use
of mineral fertilizers and locally available organic amendments (i.e., crop residues,
compost, green manures, livestock, and household waste) to provide nutrient inputs to
the soil. This approach not only improves the soil's ability to sustain plant and animal
productivity but it also increases the efficiency of all inputs, including mineral fertil-
izers (Bationo et al. 2007; Wopereis et al. 2008). In addition, ISFM promotes the adop-
tion of improved germplasm, balanced fertilization, and improved crop management
practices, including efforts to control erosion and leaching and to protect soil organic
matter content. Recent work in Central Africa has shown that ISFM relative to farmer
practice can more than double yields and significantly increase profits (Table 3.1).
Nonetheless, both productivity and fertilizer use in Africa remain stubbornly
low, in part because numerous challenges are hampering widespread ISFM adop-
tion. These include limited access to fertilizers and sufficient amounts of organic
inputs, labor constraints, and lack of a whole-farm approach that optimizes resources
to meet both commercial and food security objectives while mitigating risks. As a
result, the development of profitable, scalable ISFM strategies has been slow, and
adoption has been below expectations.
Indeed, for ISFM to be successful, it is increasingly recognized that ISFM must
be embedded in a broader strategy that includes increased availability of macro-
and micronutrient fertilizers, development of fertilizer and seed input supply chains,
output market development, and provision of credit for purchased inputs (primarily
seeds and fertilizers).

TABLE 3.1
Summary of Yield Increases Due to ISFM in the Great Lakes Region of Africa

Recommended
ISFM Practice
(Yield, kg ha −1 )

Increase in Net
Returns Due to
ISFM (US $ ha −1 )

Farmer Practice
(Yield, kg ha −1 ) Country Crop

Rwanda Potato ( Solanum

tuberosum )

8000 19,500 1600

Maize 2200 4100 700

Wheat 1400 3500 700

Burundi Potato 3200 15,900 2200

Rice 1500 3600 400

Beans ( Phaseolus
vulgaris )

400 1600 300

Wheat 300 2200 500

Democratic
Republic of
Congo

Potato 6600 19,100 2200

Rice 2300 7000 2600

Beans 200 800 100

Maize 1000 3600 600

Note: Returns reflect two cropping seasons per year.