4 - Central Institute of Brackishwater Aquaculture

Natlonal Workshop-cum-Tra~nlng on BlOlnfWWIatk8 and IfIfonnation Management in Aquacuhra
3.1 Soil and Land Resources Inventory
Remote sensing technologies through air borne and satellite-based sensors are
important tools for efficient mapping as well as monitoring of soil resources. It
has been demonstrated that space borne data afford greater degree of accuracy
and is time saving for mapping. Soil surveyor detects different soil formative
environments through visual interpretation of geological maps, topographical
maps and satellite images. The spatial extents of the soil formative environments
are then used to delineate soil-landscape units known as physiographic units.
Physiographic units are based on the relationships between these environmental
conditions and the soil mapping units. These physiographic units are often
initially delineated on a set of air photos /satellite images, then field checked and
compiled onto a base map. Soil profiles were then studied in these physiographic
units to characterize and classify the soils to prepare physiographic-soil map. The
use of satellite data for soil survey is either by digital analysis of images or by
the visual interpretation of FCCs (Hiwig and Karale, 1973; Hilwig, 1975). The
digital approach of image interpretation is quantitatively oriented, using
automated classification method, pixel by pixel. Careful visual image
interpretation can be better than digital image classification for soil resource
mapping. Ancillary data used with satellite images to improve their visual
interpretability.
The recent technology on hyperspectral remote sensing helps in quantitative
assessment of different soil parameters thereby increasing the efficiency of
expensive and time-consuming soil-related studies. The rapid nature of the
measurement (through this technique) allows soil variability to be more
adequately sampled than with conventional approaches and thereby facilitates
risk-based approaches to soil assessments. A study was conducted in IARI for for
quantitative assessment of 16 physico-chemical parameters such as texture,
moisture, colour, organic matter, soil reaction, available N, P and K,
exchangeable Ca, Mg, Fe, Mn, Cu and Zn, Calcium carbonate and oxide contents
through the hyperspectral remote sensing techniques. For site specific
management, homogenous land units can be developed using both remote
sensing and GIs techniques and fertilizer requirement for each homogenous land
units or fertility units can be recommended for various crop which has been
successfully done for Karnal District by IARI.
There are various land evaluation methods used for assessing the potential and
productivity of soil for agricultural purposes (as given below). Now a days remote
sensing tool have been used for assessing productivity potential of the land for
agriculture purpose.
i). Land Capability Classification
ii) Soil and Land Irrigability Classification
iii) Parametric methods of Land Evaluation
iv) Land Productivity Index (Storie, 1976)
v) Soil Productivity Index ( Ricquier et al. 1970)
vi) FA0 Framework of Land Evaluation (1976)