Agriculture Reference
In-Depth Information
machinery for NT farming is a major obstacle. Use of new equipment being devel-
oped can produce crop yields equal to or better than plow tillage (Johansen et al.
2012). Furthermore, appropriate cropping systems are being tested and promoted for
NT farming (Affholder et al. 2010). Despite numerous uses of NT farming, it may
not be applicable under all soils and cropping systems. Thus, a soil guide is needed to
advise small landholders about the site-specific tillage and other methods of seedbed
preparation (Lal 1985). In eastern Paraguay, Kubota et al. (2005) observed that the
NT system might not be suitable for coarse-textured Terra rossa soils.
1.4 DROUGHT STRESS
Crop yields in rainfed farming is constrained by drought stress. Droughts are disrup-
tive to the development process, and adverse impacts of drought are exacerbated by
the reluctance of small landholders to invest in water management options (Nieto et
al. 2010). Expensive modern water conservation and management technologies are
unlikely to be adopted by the poorest of the poor. Appropriate technologies must be
cost-effective, risk reducing, and productivity enhancing over a short term (Ellis-
Jones and Mason 1999). Thus, adoption of soil water conservation measures can
improve water productivity (Shaheen et al. 2011). Farmer-driven small-scale irri-
gation can be important in alleviating agronomic/pedologic droughts (Laube et al.
2012). Flexible systems of N fertilization, with variable rate according to the current
seasonal rainfall pattern, can improve productivity in semiarid areas (Masvaya et
al. 2010). Drought stress can also be managed by adoption of the Zai-type pitting
system, which originated in drier parts of West Africa (Bekunda et al. 2010). This
traditional technique integrates harvesting of water and applying nutrients/manure
through a traditional form of precision agriculture. In addition, affordable drip irri-
gation system (i.e., bucket kit for home gardens) is being tried to meet the needs of
small landholders and poor farmers in SSA, Asia, and Latin America (Postel et al.
2001). In addition to lack of water, agronomic productivity of dryland farming in
semiarid tropics is also constrained by low soil fertility (Wani et al. 2007). Thus,
judicious strategies of enhancing soil fertility can also improve water productivity.
1.5 SOIL FERTILITY MANAGEMENT
Small landholders use little fertilizers, although they are knowledgeable about soil
fertility-enhancing technologies being promoted (Enyong et al. 1999). Some of the
factors and techniques are beyond the reach of resource-poor farmers. Furthermore,
high levels of risks in drought-prone environments along with high fertilizer prices
are important factors precluding poor farmers from using chemical fertilizers
(Shiferaw et al. 2004). Therefore, nutrient recycling and the use of biological N fixa-
tion (BNF) are important in managing soil fertility in regions such as South and
Southeast Asia, SSA, the Caribbeans, and Central America. Thus, efficient man-
agement of nutrients in soils and manure is a key factor in crop production. Most
small landholders manage soil fertility by recycling nutrients through application
of animal and plant wastes. Farmyard manure (FYM) is commonly the only input
available (Rufino et al. 2007).
