Contents

Preface
I. Introduction
II. Size and Shape of Terraces
III. Planning for Terracing
IV. Methods of Terrace Marking
V. Methods of Terracing
VI. Drainage and Irrigation Channels
VII. Stabilization of Terraces
VIII. Organic Matter Recycling

Preface

The productivity and fertility of hilly area mainly depends on how better one conserves it's soil and water. Terracing is one of the best methods to conserve water and soil in sloppy areas. This booklet provides a detail information about making suitable terraces in sloppy areas.

Dr. K.T. Chandy, Agricultural & Environmental

I. Introduction

Terracing is a method of making the sloppy land into small plots of leveled fields which can be continuously cultivated under seasonal crops with minimum loss of soil and maximum conservation and use of moisture. Continuous seasonal cultivation stirs up the soil and makes it more liable to erosion. But terracing counteracts this and stabilizes the soil. Similarly, a terraced field ensures maximum i absorption of rain and irrigation water into the soil. Besides, whatever manures and fertilizers applied will remain in the soil and make available to the plants. The physical and chemical conditions of soil in a terraced field improves considerably and consequently increase the soil productivity. Similarly the organic content of the soil in a terraced plot increases more rapidly as compared to a sloppy land.

II. Size and Shape of Terraces

Terraces may be broad, narrow, long or short and straight or bent. The width of the terrace depends upon the degree of i slope. The greater the slope, the narrower will be the terraces and vice versa. Length of the terrace depends on the width of the slope (the length across the slope on a contour line) and convenience of the farmer. Whereas the shape of the terrace whether straight or crooked, depends on the curves and bent across the slope. If the contour line is bent, the terraces made on them will also be bent.

III. Planning for Terracing

Planning for terracing of a given land includes the following steps.

1. Visual survey
Through visual observation, one should assess the resources of the land. There may be springs, streams, trees, plants, rocks, stones, etc. on the land meant for terracing. He should observe the depth of the soil and also should estimate the degree and length of the slope (top to bottom distance).

2. Location of permanent structures
In this step one identifies the location of permanent structures and their placement. The permanent structures in a terraced farm land will be the walls of the terraces, irrigation and drainage channels, path and roads, farm houses, compost pits, ponds for collection of surplus run-off, electrical installations, pump sets, threshing field, storage, animal sheds, etc.

He will also observe the width of the slope in horizontal direction which gives the length of contour line. He should visualize each terraced plot in his mind and all other permanent structures on the land and initially check whether each permanent structure is properly placed or not.

3. Marking of each terrace
Marking of the terraces can be done in two ways: fixed vertical height and fixed horizontal width. Sometimes they are also marked as irregular type. They are briefly explained here.

a. Fixed vertical height
In this method the marking of the terraces is done at a fixed vertical height which may be conveniently fixed between 1 to 4 feet. However, it is more than 4 feet. The disadvantage of this type of marking is that the terraces will not be uniform in width. When the cut portion of soil is left as a mud wall, fixed vertical method is more suitable than fixed horizontal width. Otherwise the mud walls will easily collapse. The mud wall is cut slanting and should be covered with grass growth to reduce chances of collapsing.

b. Fixed horizontal width
In this type, marking is done by keeping the width of the terrace relatively same. The advantage of this method is that one gets terraces of relatively uniform width. Such uniformity helps to use implements for ploughing and intercultural operations. The disadvantage of this method is that the height of the vertically cut portion of the land will be varying. Under such situation, one has to treat the mud wall by compacting material, build up the wall with bricks or stones with or without cement or any other binding material. In other words, the collapse of the mud wall should be prevented mechanically.

c. Irregular type
When irregular type of terraces are made, the vertical (height) and horizontal (width) distances of the terraces vary considerably. The terraces are made at random without any uniformity in size and shape. At times due to excessive undulating condition of the land, it is not possible to have the terraces made in uniform size, shape or height of the wall. Under such situations, terraces are made without any uniformity.