Terracing
In
Maharashtra, terracing is initially done at Govt. cost and then the amount is recovered
from cultivators as loan along with concessional rate of interest in suitable annual
installments. 62p.c. of the loan is treated as subsidy. Terracing has become popular in
Sahyadri ranges of Maharashtra. It is suitable on bigger slopes up to 10p.c., and where
rainfall is higher than 1,250mm. Terrace bunds consist of comparatively narrow embankments
constructed at intervals across the slope and the vertical spacing between bunds may vary
from 1 to 2m., depending upon the slope, type of soil, rainfall etc. Bench terracing is
done when gradient is steeper than 10 p.c., as a series of step like platforms along
contours. These terraces are like tabletops sloping outwards and are provided with stone
wasteweirs ot drain away surplus water. Angular and big boulders should be used for
terrace outlets because round and small boulders will slip and get dislodged under the
gushing water. Terracing is generally very costly and the cost may come to Rs.2,500 to
5,000 per hectare.
Terracing
of side slopes: - The uneven side slopes of the medium gullies having 8 to 15% slope are
bench-terraced into level terraces at 0.9 to 1.2m vertical intervals. The terraces are
given a back slope of 1 in 50 and a longitudinal grade of 1 in 200 towards the grassed
outlet. A ridge bund of 0.3 sq m cross-section is provided at the edge of each terrace.
Terrace faces are given a slope of 1.5:1. Bench terraces are constructed when the gully
sides are having a uniform slope for a length of at least 120m to justify the cost of
terracing. The terrace faces, grassed outlets and earthen check dams are stabilized by
sodding or growing them with suitable grasses. Dicanthium annulatum and Cenchrus
ciliaris have been found suitable for this purpose, specially in Gujarat and in the
ravines on the banks of the Jamuna river. Bench terraces and the check dams require
careful maintenace for the first two years in view of the unsettled conditions of the
soil. Bench terraces may be sloping outward or inward with or without a slight
longitudinal grade, according to the rainfall of the tract medium, poor or heavy, and the
soil and the subsoil are fairly absorptive or poorly permeable. On steeply sloping and
undulating land, intersive farming can be practised only with bench-terracing. The initial
cost of bench-terracing is more than that of bunding. However, bench-terracing helps to
retain the soil, moisture, manure and fertilizer better and facilitates the application of
irrigation, if available. In rainfed areas, terracing is usually practised on slopes
ranging from 6 to 33 per cent. It may have to be used on gentle slopes, if irrigation is
to be applied to the crop. |
Ag.
Technologies
(Agricultural
Engineering)
|