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Agriculture / Soil
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Estimating Carbon-fixation in India based on Remote Sensing Data
4.Results and Discussions
4.1 Interannual variations in Carbon-fixation
The monthly biomass and carbon fixed in the Indian territory during the years 1987, 1988 and 1989, as calculated using the above steps, are shown in table 1. For all the three years, there seems to be a general trend of change in monthly biomass generation and C-fixation. The biomass and cosequently C-fixation, starts building up in the month of January and reaches its peak in the month of February/March and then drops suddenly in April. The biomass generation and C-fixation remains low in the summer months of May and June. This again starts building up in July/August and reaches its peak in September/October and the falls suddenly in November. Thus, we observed two peaks of carbon-fixation; first in the months of Feb/March and second in the month on October/November. Whereas, two low C-fixation peaks are also observed in the months of April and November.
These high and low peaks of carbon-fixation clearly corresponds with the two crop growing seasons in India. The winter crops are sown in the month of November/December and they reach their peak vegetative state in the month of Feb./March and are harvested in the month of April. The agricultural lands generally remain fellow during the summer months of May and June, corresponding to low rates of C-fixation. The summer crops are sown in the months of June/July after the onset of monsoon and they rearch their peak vegetative stage in the month of Sept./Oct. before harvesting in November. Sowing of winter seson crops starts in the end of November or December and therefore, the biomass remains low during these months. Thus, this interannual variation in the rates of C-fixation indicated that agricultural C-fixation plays a major part in the total terrestrial biomass production in India as more than 45 per cent of the total geographical area in India is under cultivation.
Table 1. Estimates of total biomass and carbon-fixation in India.
| Months |
Biomass(million tons) |
Carbon-fixation (million tons) |
| 1987 |
1988 |
1989 |
1987 |
1988 |
1989 |
| Jan. |
64.71 |
86.39 |
123.75 |
29.12 |
38.88 |
55.69 |
| Feb. |
101.03 |
91.03 |
127.35 |
45.46 |
40.96 |
57.31 |
| Mar. |
84.40 |
88.02 |
108.31 |
37.98 |
39.61 |
48.74 |
| Apr. |
45.71 |
35.79 |
74.71 |
20.57 |
16.11 |
33.62 |
| May. |
63.51 |
53.89 |
53.62 |
28.58 |
24.25 |
24.13 |
| Jun. |
56.78 |
49.41 |
46.55 |
25.55 |
22.23 |
20.95 |
| Jul. |
42.99 |
37.61 |
67.61 |
19.35 |
16.92 |
30.42 |
| Aug. |
79.85 |
90.79 |
104.35 |
35.93 |
40.86 |
46.96 |
| Sep. |
127.28 |
157.25 |
182.13 |
57.93 |
70.76 |
81.96 |
| Oct. |
149.10 |
165.10 |
224.50 |
67.10 |
74.30 |
101.03 |
| Nov. |
95.89 |
131.94 |
134.15 |
43.15 |
74.30 |
60.37 |
| Dec. |
83.30 |
110.35 |
97.17 |
37.49 |
49.37 |
43.73 |
| Annual |
878.77 |
945.96 |
1278.35 |
395.45 |
425.68 |
575.26 |
4.2 Annual variations in Carbon-fixation
Total biomass generation of 878.77, 945.96, and 12778.35 million tons was estimated in India for the years 1987, 1988 and 1989, respectively with a corresponding annual C-fixation of 395.45, 425.68 and 181.16 million tons for same years (Table 1). The performance of monsoon is the single most important factor effecting the growth of vegetation and consequenly monsoon is the single most important factor effecting the growth of vegetation and consequenly agricultural productivity in India. A study in the behavior of Indian monsoon showed that it was normal for the year 1989. But it showed a negative anomaly during 1987 and a positive anomaly during 1988 causing drought and floods in the two years, respectively. Therefore, the growth of vegetation and agricultural productivity was reduced in both the years. This interannual anomaly in carbon-fixation could also be described through the present methodology using PEM. The highest annual carbon-fixation of 575.26 million tons was estimated for the year 1989 as compared to 425.68 and 395.45 million tons for the years 1988 and 1987, respectively.
4. Conclusions
Based upon the present study it could be concluded that the PEM cvan be used to make fairly correct estimates of biomass and carbon-fixation on a regional and global basis. Most of the parameters used in the PEM can be derived from the remotely sensed data. The model was also able to describe the annual and interannual variations in biomass production and carbon-fixation in the region. Therefore, the technique developed in the present study based upon the use of remote sensing data seems to have a great potential for making quick and accurate estimates of biomass and carbon-fixation over a large region.
8. Reference
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