Agriculture Reference
In-Depth Information
CA has been, characteristically, taken up by households on the basis of some specific
elements (options) in varying combinations. Farmers consistently practicing a com-
bination of CA practices that took on board all the principles of CA were still rather
few in all the project sites. Depending on the varying local circumstances, com-
munities/households innovated on the most feasible and attractive “entry points” in
terms of which practices were tried/adopted first. In Kenya, especially in drier areas,
options related to reduced tillage were the most popular, while in Tanzania, the good
markets and price for lablab seed provided a good incentive for farmers to “enter”
along the soil cover/live cover crop (lablab) option.
Löfstrand (2005) observed in Babati District, Tanzania, that low soil fertility was
a limiting factor of crop production in the district, and recycling of plant nutrients
to the arable land was low. In this study, soils from three different CA practices,
FYM and intercropping with legumes, intercropping with rock phosphate, and inter-
cropping under leguminous
Faidherbia albida
tree, were compared to investigate
how different treatments have influenced soil fertility (Löfstrand 2005). FYM and
intercropping with legumes improved soil fertility, and application of rock phos-
phate enhanced the availability of phosphorus and also increased soil pH. When
only rock phosphate was applied, crop yields were low and the amount of nutrients
either decreased or showed no significant change. Intercropping under leguminous
F. albida
trees produced the highest maize yields and also resulted in the highest
level of P and N in the soil. In all these case studies, however, the effectiveness of
CA practices to mitigate the adverse impacts of, and to adapt to, climate change were
not explicitly taken into account, including assessment of soil and ecosystem carbon
pools and carbon/water footprints of production systems.
In Tanzania, conservation tillage is the focus of farmers and researchers who
are working in areas prone to soil erosion. This is because in conservation till-
age, crops are grown with minimal cultivation of the soil, and most or all crop
residues remain on top of the soil rather than being ploughed or disked into the
soil. Tillage has long been a traditional agricultural system. In Tanzania, fallowing
and using organic matter are practices that farmers traditionally used to main-
tain and to restore soil fertility. These practices have been used for a long time
until the 1950s, when the government agricultural extension programs promoted
soil and water conservation practices to control surface runoff, such as stone and
earth bunds, ridging, pitting, infiltration or cutoff drains, bench terraces, and
contours (Shetto and Owenya 2007). Strategies that are aimed at combating land
degradation through mechanical and biological measures—reforestation activi-
ties, agroforestry, protection of water catchments, improved land husbandry, and
environmental conservation in general—were initiated in Tanzania by the late
1980s (Shetto 1999). As a way to complement the Tanzanian government efforts,
a study was conducted in the Uluguru Mountains, Tanzania, to investigate the
effect of conservational tillage on vegetable yield in the area (Msita et al. 2010b).
The practices that were examined include control conservational tillage (CCT),
conservational tillage with manure (CT), conservational tillage with
in situ
com-
posting (CTG), control traditional tillage (CTT), traditional terrace with manure
(TT), and traditional tillage with
in situ
composting (TTG). The results obtained
demonstrated that all conservational tillage treatments gave higher yield (CCT =
