Agriculture Reference
In-Depth Information
improved yields, through soil and crop management, may be achieved by the right
combination of genetically improved crop varieties coupled with better agronomic prac-
tices, in the face of deteriorating soil quality, increasing water shortages, and other uncer-
tainties brought about by climate change (Fan et al. 2012).
The Sloping Agricultural Land Technology proposed by Tacio (1993) uses an inte-
grated and holistic approach through a combination of terracing, contour operations,
fodder hedge rows, agroforestry, and mixed cropping. The approach, tailored to local
conditions, is likely to be compatible with sustainable hill farming in the Himalayan
region. Indeed a “whole landscape” approach, using place-specific strategies combin-
ing crop diversification and improved soil, crop, and livestock management, along
with agroforestry, are likely needed to achieve sustainable land use through targeted
policy and management interventions (DeFries and Rosenzweig 2010).
6.5 FUTURE PRIORITIES FOR FOOD SECURITY
AND ENVIRONMENTAL PROTECTION
It is amply evident that demands on land and water resources will continue to increase
and that further intensification of agriculture will be required to meet global food
demands in the future. Under the present trends of increased agricultural intensifica-
tion in the richer nations and increased land clearing in poorer nations, it has been
estimated that about 1 billion hectares of land would be cleared globally by 2050
with greenhouse gas emissions reaching about 3 Pg y
−1
of CO
2
equivalent and nitro-
gen use reaching approximately 250 Mt y
−1
(Tilman et al. 2011). Local land use deci-
sions can have global implications for terrestrial carbon stocks and global climate
change in view of the food demands of a growing population, changing diets, and
biofuel production. Tropical areas have been calculated to lose nearly twice as much
carbon (about 3 Mg C per million grams of annual crop yield), while producing less
than half the annual crop yields compared with temperate regions (West et al. 2010).
Thus, special emphasis is needed on increasing yields from existing croplands in the
tropics rather than clearing new lands.
Agricultural intensification has been typically characterized by a synergy
between agronomic innovations and plant breeding (Evans 2003). Globally, agricul-
tural intensification has been able to keep pace with population growth through con-
tinuous evolution; it is estimated that about 2 million hectares of land are affected by
soil erosion, 1.5 million hectares by salinization and toxification, and even greater
amounts of land are permanently lost due to urban expansion onto arable land (Evans
2003). Therefore, more innovative, integrated, and sustainable production systems
will be needed to keep pace with demands in the future. Genetically improved seeds
and crops are already in use worldwide and likely to be an important part of agri-
cultural sustainability. Hence, the use of high-yielding varieties enhanced through
genetic modification is expected to be a crucial part of the solution to raise global
yields without further degrading the environment (Ronald 2011). However, studies
suggest that the expected future food demand cannot be met by increasing genetic
yield potential alone as the gap between average farm yields and genetic potential
is narrowing (Cassman 1999). Therefore, a combination of soil quality improvement
along with greater precision in agricultural management choices (crop, nutrient,
