Abstract:
Soil quality and agricultural sustainability are required to feed about nine
billion people by the year 2050. To feed such a population, the planet ought to
increase food production by 60%. To attain agricultural sustainability, there should
be a balance among biophysical, economic and social dimensions under which soil
quality is a core aspect. It is worthwhile to explore soil quality versus agricultural
sustainability in sub-Saharan countries because the population is expected to
increase by 80%. This chapter reviews the current agronomic practices in countries
characterized by semiarid agro-ecological zones and their implications to soil quality
and agricultural sustainability, using Tanzania as a case study.
We found that agro-pastoralism based on maize, sorghum, millet, sheep, cattle and cow
is a current dominant agricultural system but with low yields. Monoculture has contributed
to the degradation of soil quality. Drought has raised issues to already stressed
ecosystems and made rain-fed agriculture a vulnerable and unsustainable livelihood
for smallholder farmers. This situation has reduced the per capita grain harvested area
from 0.6 to less than 0.4 ha and thus, affected for more than 70% the smallholder farmers’
livelihoods. Fortunately, areas using fertilizations of animal manure and other
organic soil management practices have increased soil fertility and crop yields from
0.82 tn ha−1 under no-fertilization to 1.8 tn ha−1 under organic fertilization.
