4 - Central Institute of Brackishwater Aquaculture

National workshop-cum-Training on Biointonnatia and Infomation Management in Aquaculture
The Normalized Difference Vegetation Index (NDVI) being a potential indicator
for crop growth and vigour was used in study. The mathematical expression for
NDVI is given as
(NIR - Red)
NDVI =
(NIR + Red)
Based temporal NDVI profile derived from images of different dates different
crops and their spatial distribution was computed using ground truth data
collected using GPS (Fig 8). It was found that out of about 2.27 lakh ha of study
area, various agricultural crops cover 59 per cent. The wheat crop was found to
be dominating one (20%) followed by maize (12 %) and lentil and chick pea (10
O/O). In wheat growing areas, about 2, 12 and 6 percent area was occupied by
early, timely and late sown wheat respectively. Similarly, in maize crop, 8 and 4
percent was in early and late sown categories respectively. Winter maize and
wheat is grown majorly in flood plains close to river bank (locally known as diara
land), pulses are common in low lying areas called tal lands. Arhar crop sown
during May/June if not damaged by flood remains in the field upto late March
/early April. Other 41 per cent includes built up area, orchardslplantation areas,
barren lands, river, water bodies etc. Digitized map of Bhagalpur with village
boundaries was also overlaid to retrieve the information about late planted crops
and fallow lands for possible interventions.
Figure 8 Spatial distribution of crops grown (rabi,1999-2000)
village boundaries of Bhagalpur district, Bihar
overlaid with
4.1.3 Addressing the seasonal dynamism of agricultural system
Dynamism of crops over an agricultural calendar can be captured from 10 days
maximum value composite satellite data products like NDVI images of SPOT-4
vegetation sensor. NDVI data from a satellite sensor is primarily related to
vegetation changes and follows annual cycle of growth and decline. Thirty six
NDVI images of 10 days composite for the agricultural calendar year June 1999-
May 2000 were stacked together to derive temporal NDVI profile. Clouds and