Agriculture Reference
In-Depth Information
transport of fertilizer adds to the footprint as a ton of fertilizer transported
over 1 km releases about 1 kg of CO
2.
Soil fertility is most essential for sustaining productivity and integral-
ly depends on a complex network of soil structure and balanced water,
oxygen and nutrients availability. Soil fertility is influenced by crop cul-
tivars, growth promoting microbes and inorganic, organic absorber stabi-
lized slow release fertilizers. In developing soil fertilities and a sustaining
human subsistence an optimal crop selection and growth management, a
skilled handling of growth promoting microbes, and a flawless application
of fertilizers are potential strategies.
The sensitivity of soil carbon to warming is a major uncertainty to
projections of carbon dioxide and climate. According to Hari Eswaran et
al. (1993), the C stored in soils is nearly three times that in the above
ground biomass and approximately double that in the atmosphere. Glob-
ally, 1576 Pg of C is stored in soils, with ~506 Pg (32%) of this in soils of
the tropics. It is also estimated that ~40% of the C in soils of the tropics is
in forest soils. Experimental studies indicate increased soil organic carbon
(SOC) decomposition at higher temperatures, resulting in increased CO
2
emissions from soils. But recent evidences favor against this theory. The
initially increased CO
2
efflux returns to the prewarming rates within 1-3
years, and apparent carbon pool turnover times are insensitive to tempera-
ture with non-labile SOC showing more sensitivity to temperature than
labile SOC (Knorr et al., 2005). Significantly more carbon is stored in the
world's soils than in present in atmosphere. Disagreements exist, regard-
ing the effects of climate change on global soil carbon stocks. Despite
much research, a consensus has not yet emerged on the temperature sensi-
tivity of soil carbon decomposition due to differential kinetic properties of
diverse soil organic compounds (Davidson and Janssen, 2006)
Soil fertility depletion is the fundamental biophysical cause declin-
ing productivity (Pawlson, 2005). Citrus-based farming system has high
potential for sequestering carbon for mitigation of climate change. The
perennial nature of citrus trees act as carbon sinks by sequestering the
atmospheric carbon. Modifying fertilizer application to enhance nutrient
availability, use of soil amendments to improve soil fertility providing
irrigation at critical growth stages and conservation of soil moisture are
important interventions. Considerable studies have into questions of just
how climate change will affect crop and soil productivity. However, the
problem of predicting the future course of citrus cultivation in a changing
