Agriculture Reference
In-Depth Information
6.4.2 C
rop
r
otatIons
and
C
roppIng
p
atterns
Cropping patterns that include legumes with cereal crops or combinations of crops
(intercropping) offer potential for improved soil quality, reduced production risks,
and better return to farmers. Sherchan et al. (1997) reported that planting pigeon
pea with groundnuts had a beneficial effect on soil physical properties along with
increase in maize yields (Table 6.3; 2.42-2.53 Mg ha
−1
vs. 1.124 Mg ha
−1
) over the
traditional maize-millet cropping pattern. Correspondingly, soil properties such as
SOM, bulk density, and available water capacity were more favorable in pigeon pea
and groundnut and sole groundnut cropping patterns (Table 6.3). Moreover, Sherchan
and Karki (2006) point out that because pulses and beans are an important source of
dietary protein for rural communities in the region, development of improved varie-
ties of legumes with higher N-fixing capacity would help enhance the sustainability
of cropping systems. Sharma and Sharma (2004) in India also concluded that inclu-
sion of a legume in the crop rotation, such as rice-potato-mung bean, along with a
combination of chemical fertilizers and FYM, was highly effective in building up
SOC, nitrogen, phosphorus, and potassium levels in soil.
6.4.3 B
IofertIlIzatIon
and
s
eed
I
noCulatIon
Another promising technique for enhancing sustainability through efficient uptake
of crop nutrients is the use of biological agents such as algae, bacteria, and non-
crop plants. Quyen and Sharma (2003) noted that a combination of green manure
(
Sesbania
sp.), blue-green algae, and
Psuedomonas striata
inoculations, with FYM
application, gave the highest rice yields. The yield (5.2 Mg ha
−1
) of this organically
grown rice was greater than that obtained using high chemical fertilizer doses.
The use of rhizobial inoculants for seeds of leguminous crops such as soybean, black
gram, chickpea, cowpea, mung bean, and groundnuts (Table 6.4), as well as other plants
like
Desmodium
,
Stylosanthes
,
Medicago
, and vetch, have been shown to be effective
TABLE 6.3
Soil Properties and Yield of Maize Test Crop under Different
Cropping Patterns
Bulk Density
(Mg cm
−3
)
Maize Yield
(Mg ha
−1
)
Cropping Pattern
SOM (%)
AWC (%)
Maize-millet
0.77
1.65
11.47
1.12
Groundnut
0.91
1.54
12.99
2.42
Pigeon pea + groundnut
1.01
1.56
12.84
2.53
Source:
Modified from Sherchan, D.P., G.B. Gurung, and B.D. Gurung. 1997.
Productivity assessment of red clay soils with legume and cereal combina-
tions on dry, rainfed hill environments in Nepal. PAC Technical Paper
No. 180. Pakhribas Agricultural Centre, Dhankuta, Nepal.
Note:
AWC, available water capacity; SOM, soil organic matter.