Agriculture Reference
In-Depth Information
TABLE 1:
Chemical composition of crop residues applied in rice-wheat-mung bean
cropping system
Composition
(mg kg
−1
)
2006 to 2007
2007 to 2008
Rice
Wheat
Mung bean
Rice
Wheat
Mung bean
Total N
4,700
3,900
15,000
5,000
4,100
15,200
Total P
680
490
1,100
700
500
1,200
Total K
14,600
15,600
4,400
14,650
15,700
4,500
Organic C
408,000
400,000
401,000
410,000
403,000
403,000
Fe
434.23
349.80
849.56
437.41
372.97
876.21
Zn
100.52
29.89
69.13
105.09
34.67
72.04
Mn
58.23
73.69
79.65
60.69
78.52
88.62
Cu
40.02
16.85
22.23
40.67
17.43
23.04
6.2.3 ANALYTICAL TECHNIQUE
Grain and stover samples of mung bean were dried in hot air oven at 60°C
for 6 h and ground in a Macro-Wiley Mill (Paul N. Gardner Company,
Inc., FL, USA) to pass through a 40-mesh sieve. A representative sample
of 0.5-g grain and straw was taken for the determination of nitrogen, phos-
phorus, and potassium. The nitrogen concentration in grain and straw sam-
ples was determined by modified Kjeldahl method (Jackson 1973); total
phosphorus, by Vanadomolybdo phosphoric acid yellow color method and
flame photometry method, as described by Prasad et al. (2006). The NPK
concentration in grain and straw was expressed in percentage. Iron, zinc,
manganese, and copper were determined in diacid digest of plant tissues
using AAS as in the case of soil analysis. The N, P, and K uptake in grain
or straw was worked out by multiplying their percent concentrations with
the corresponding yield. The total uptake of N, P, and K was obtained by
adding up their respective uptake in grain and straw. This was expressed in
kilogram per hectare. Protein content in mung bean grains was obtained by
multiplying the N concentration of grain with a factor 6.25 (Juliano 1985).
The protein yield of mung bean was calculated by multiplying its protein
concentration with grain yield.
