Land capability:

Land capability classification is an interpretative grouping of soil mapping units mainly based on inherent soil characteristics, external land features and environmental factors that limit the use of land for agriculture, pasture, or other uses on a sustained basis (IARI, 1971). The 121 soil map units of the State have been grouped into five land capability classes. The extent of the area under each association is given below.

About 83 percent of the area is suitable for agriculture and about 17 per cent is not suitable for agriculture but well suited to forestry, pasture, silvi-pastoral system, mining, quarrying and wild life and recreation. Of the lands suitable for agriculture, about 19 per cent are good cultivable lands (Class II) with minor limitations of soil texture, drainage, salinity and sodality and erosion, about 41 per cent are moderately good cultivable lands (Class III) with problems of erosion, slope, gravel content, surface crust formation and drainage, and about 23 per cent are fairly good cultivable lands (Class IV) with problems of soil texture, shallow rooting depth, gravelliness, erosion, drainage and climate.

 

Land capability of soils in Karnataka

Land capability class

Description

Area

‘000 ha.

(%)

II

Good cultivable lands having minor problems of soil texture, drainage and erosion.

3548.9

18.6

III

Moderately good cultivable lands having moderate erosion, slope, drainage and soil* problems.

7746.9

40.7

IV

Fairly good cultivable lands having severe erosion, drainage, climate and soil problems.

4411.3

23.2

VI

Land well suited for grazing and forestry, having severe erosion, topography and soil problems.

2745.9

14.4

VIII

Lands suitable only for wildlife, recreation and quarrying.

486.4

2.5

Miscellaneous Water bodies,urban area 110.5 0.6

*Soil problems: depth, texture, gravelliness, surface crusting and compaction,   salinity, sodicity.

landcap.gif (177294 bytes)

Source: NBSS&LUP,R.C.,Bangalore / KSDA

line1.gif (3601 bytes)

 

Land Irrigability:

Land irrigability classification is an interpretative grouping of soils based on physical and socio-economic factors in addition to the soil irrigability and is primarily concerned with predicting the behaviour of soils when they are brought under irrigation (IARI, 1971).

Land suitable for irrigation are grouped under classes 1 to 4 according to their limitations. Lands not suited for irrigation are grouped under classes 5 and 6.

The soils of Karnataka were grouped into four irrigability classes. Nearly 82 percent of the area of the State is suitable for irrigation, and 18 per cent is not suitable. Of the land suitable for irrigation, about 19 per cent is good irrigable land (class 2) with moderate limitations of soil texture, drainage and slope, about 46 per cent is moderately good irrigable land (class 3) with severe limitations of slope, stoniness and gravelliness and soil depth, about 17 per cent is marginal irrigable land (class 4) with very severe limitations of topography, soil depth, gravelliness and stoniness.

Land irrigability of soils in Karnataka

Land Irrigability class

Description

Area

‘000 ha.

(%)

2

Lands that have moderate limitations of soil and drainage for sustained use under irrigation.

3701.1

19.4

3

Lands that have severe limitations of soil, drainage and slope for sustained use under irrigation.

8696.6

45.7

4

Lands that have very severe limitations of topography and soil for sustained use under irrigation.

3224.9

16.9

6

Lands not suitable for irrigation due to topographic, soil and rock exposure limitations.

3316.7

17.4

Miscellaneous Water bodies,urban area 110.5 0.6

 

landirr.gif (172010 bytes)

Source: NBSS&LUP,R.C.,Bangalore / KSDA

 

Soil depth:

Depth of the soil determines the effective rooting depth for plants and in accordance with texture, mineralogy and gravel content, the capacity of the soil column to hold water.

To classify the soil map units into depth classes, some generalisation in respect of depth classes has been made as large number of combinations occur. Accordingly, six depth classes have been made and the extent of area under each class has been given below.

Soil depth classes

Class

Depth

(cm)

Area

‘000 ha.

(%)

Extremely shallow

00 - 10

76.3

0.4

Very Shallow

10 - 25

2547.9

13.4

Shallow

25 - 50

497.8

2.6

Moderately shallow

50 -75

1706.4

9.0

Moderately deep

75 - 100

2717.1

14.3

Deep

>100

10907.7

57.3

Miscellaneous-Rockland,Water bodies,urban area - 596.9

  3.0

 

soildepth.gif (166660 bytes)

Source: NBSS&LUP,R.C.,Bangalore / KSDA

 

NIC-AGRI