Agriculture Reference
In-Depth Information
systems, which may not sequester SOC. Enhancing rotation complexity can
sequester an average of 20 ± 12 g C m
−2
year
−1
, excluding a change from continu-
ous corn (
Zea mays
L.) to corn-soybean (
Glycine max
L.) rotation, which may not
result in a significant accumulation of SOC. The rate of SOC sequestration upon
conversion from CT to NT can peak in 5 to 10 years, with SOC reaching a new
equilibrium in 15 to 20 years. Changes in agricultural practices for the purpose of
increasing SOC must either increase inputs of biomass C to the soil or decrease
decomposition of SOM and oxidation of SOC, or a combination thereof (Follett
2001; Paustian et al. 2000).
A menu of management options is being promoted by the Central Research
Institute for Dryland Agriculture (CRIDA) in farmers' participatory action mode
diverse physical and ethnic regions of Andhra Pradesh. Some RMPs being pro-
moted include CR retentions, FYM, biofertilizers, inclusion of legumes in the crop-
ping sequence or as intercrops, green manure crops, green leaf manuring, tank silt
addition, and vermicomposting along with chemical fertilizers (Srinivasarao et al.
2011a,b,c,d). Among them, green leaf manure (GLM) with
Gliricidia sepium
is the
most promising and climate-smart technology.
Gliricidia
, commonly known as
Kakawate
, used as insecticide, repellant, and rodenticide, can thrive in dry, moist,
acidic soils or even on degraded soils under rainfed conditions. The GLM is one
of the important practices for increasing SOM concentration. Most degraded and
depleted soils lack sufficient amount of N. Growing
Gliricidia
plants on farm bunds
serves a dual purpose of producing GLM rich in N and conserving soil (Srinivasarao
et al. 2011c). Farm bunds could be productively used for growing N-fixing shrubs
and trees to generate N-rich loppings. For example, growing
Gliricidia sepium
at
a close sparing of 75 cm on farm bunds could provide 28 to 30 kg N ha
-1
year
-1
in
addition to being a valuable source of organic matter (Wani et al. 2009). Indeed,
the integrated nutrient management (INM) strategy is important to improving soil
quality for enhancing water use efficiency (WUE) and increasing farmers' incomes.
Farmers should, therefore, be encouraged to grow
Gliricidia
on farm bunds and bor-
der of fields for use in crop production, which is a sustainable means of maintaining
soil fertility along with being a source of nutrients.
16.10.1.1 Improvement of Crop Yield through
Gliricidia
Green Leaf Manuring
Using GLM of
Gliricidia
can enhance soil productivity and increase crop yields
of several rainfed crops. The impact of mulch-cum-manuring with
Gliricidia
on
the productivity of castor showed a threefold increase compared with that of the
control and one-and-a-half-fold increase in comparison with application of FYM
and fertilizer (
Table 16.10
). Yield response of different rainfed crops to
Gliricidia
GLM has been positive in many regions including that of finger millet in red soils of
Karnataka, groundnut in red soils of Andhra Pradesh, pearl millet in light-textured
soils of Gujarat, and sorghum in medium to deep black soils of Maharashtra. At
Bhubaneswar, in acid red and lateritic soils, maize yield improved from 1.7 to 2.1 Mg
ha
-1
with
Gliricidia
GLM equivalent to 20 kg N ha
-1
(AICRPDA 2008-2010). In a
long-term manurial experiment on Alfisols of a CRIDA farm near Hyderabad, sor-
ghum and green gram yields were significantly higher with the addition of 1 to 2 Mg
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