WATER CONSERVATION PRINCIPLES AND PRACTICES

Water conservation “The conservation treatment meant to reduce or prevent erosion while achieving the desired moisture conservation and/or runoff disposal.”

Important principles Increasing the time of concentration and thereby allowing more runoff water to be absorbed and held in the soil profile. Intercepting a long slope into several short ones, so as to maintain less than a critical velocity for the runoff water; and Protection against damage owing to excessive runoff.

Practices for water conservation Engineering measures: Hillside ditches Bench terraces Stone walls Broad-based terraces

Engineering measures Hillside ditches A series of shallow ditches built along the contour lines of a hill side slope at proper interval

Objectives To break up a long slope into several short slopes, in order to intercept runoff water The ditches may also serve as farm paths to facilitate transportation that the operating cost may be reduced.

Bench terraces A series of level or nearly level platform built along the contours at suitable intervals.

Objectives To intercept runoff and control soil erosion. To make cropping operations possible and safe on crop slope land.

Stone walls Using stones to construct at a suitable spacing on crop land along contour lines

OBJECTIVES T makes good use of rocks and stones existing on slopes, thereby clearing the land for cultivation. .to reduce soil and water losses and to trap the soil washed down from above, thus gradually building up bench terraces and hillside ditches in later years. To minimize the gradient of a slope to facilitate cultivation, mechanized operations and soil conservation

Broad based terraces A series of shallow, broad based terraces constructed on gently sloping land at a suitable spacing along the contour lines.

Objectives To break the length of a slope to control soil erosion To conserve soil moisture so as to help crop growth.

Grass planting on hill side ditches The establishment of specific grasses on hillside ditches, including both bottom and side slopes of each ditch.

Objectives To stabilize the hillside ditch and thus reduce maintenance cost. To save the labor costs of weeding. To prevent soil erosion on the upper side slope of the ditch and to gradually reduce the slope as sliding soil is trapped by the grass.

Agronomic and vegetative measures Contour planting Grass planting on hillside ditches Planting grass on risers of terraces Cover crops

Grass barriers Mulching Green manure Windbreaks

Agronomic and vegetative measures Contour planting: Plowing, furrowing and planting along the contour lines of a slope.

Objectives To increase water penetration into soil and conserve soil moisture To control runoff and soil erosion.

Planting grass on risers. The planting of suitable grasses on the risers of bench terraces. Objective. To prevent soil erosion from the risers and to maintain the stability of the terraces.

Cover crops Plants which are grown to cover the surface of the ground with dense foliage, to control soil erosion and improve the soil.

Objectives To protect the surface of the soil from splashing of rain drops. To built up soil organic matter To suppress weed growth and surface management cost. To minimize changes in micro-climate and in soil temperature, thereby providing a better environment for crop growth.

Green manure. A green manure crop is grown specially to improve soil and act as a fertilizer.It is plowed into soil while still green,or shortly after it matures

Objective To increase organic matter and nutrients in the soil,and to improve the physical and chemical characteristics of soil to increase the resistance of soil to erosion.

Grass barriers Contour planting of suitable spaced strips of grass on slope land.

Objectives To arrest runoff so as to reduce soil and water losses and to hold soil and prevent it from being washed downhill. To reduce the slope of a hillside cultural practices and mechanical operations. To gradually convert the barriers into bench terraces

Windbreaks. . Strips of trees or tall grasses planted at appropriate intervals to prevent or reduce wind erosion and crop losses caused by wind.

Objective To control wind erosion To reduce physiological or mechanical injuries to crops caused by strong winds. To reduce evapotranspiration To reduce salt damages if the locality is near the area.

Objective To arrest runoff so as to reduce soil and water losses and to hold soil and prevent it from being washed downhill. To reduce the slope of a hillside to facilitate cultural practices and mechanical operations. To gradually convert the barriers into bench terraces.

Drainage Diversion ditches: A ditch constructed approximately along the contour of a slope for the purpose of intercepting surface and diverting it to a suitable outlet.

Objectives. To protect farmland and buildings by diverting runoff from hill slopes. To control gully erosion.

Drainage ditches Drainage channels running along a slope, which are lined with stone, brick, or concrete etc.

Objectives To ease the flow of runoff water and to protect the ditch from erosion. To gather water flow in hillside ditch and contour drainage channels, and carry the flow to a safe place to be discharged.

Grassed water ways. Earth waterways planted with grasses to control soil erosion.

Objectives To provide safe outlet for runoff water. To prevent soil erosion and to stabilize waterways. To facilitate the operations of farm machinery. To maintain a stable field environment.

CONTOURING

DEFINITION Plowing, furrowing, and planting along the contour lines of a slope. It is a tillage practice of plowing the land in slopy areas across the slope. Not along the slope.

PROBLEMS OF SLOPY AREAS there are two main problems in slopy areas related to crop growing Water conservation Soil erosion

OBJECTIVES To increase water penetration into the soil. To conserve soil moisture. To control run off. To control soil erosion.

APPLICATION This practice should be adopted where ever cultivated crops are grown on slope land.

OPERATIONAL PROCEDURE When hilly side ditches broad-based terraces or stone walls exists, they should be used as guidelines for plowing, furrowing and other cultivational operations. The most adequate number of long rows along the guidelines is 4-6. Short rows should be positioned in the middle between two guidelines.

CONTOUR STRIP CROPPING In this continuous row crops are replaced by strips of row crops and alternating with strips of forage crops. Row crop strips must be sized to minimize run off, soil erosion. Forage strips must be wide enough to slow and filter the run off. Erosion reduction is about 50% greater than with comentional contour planting.

NOTE This conservation practice is more popular than terracing for slopes because of its lower cost for erosion control. Contour farming can reduce soil loss by 50% on slopes of 2-8% and not more than 300ft. Long.

Terracing Pieces of land at the same elevation are separated as an independent field water stay in it. When water level reach higher in one piece of land then it will moves down.

Terracing is a soil conservation practice applied to prevent rainfall runoff on sloping land from accumulating and causing serious erosion. Terraces consist of ridges and channels constructed across-the-slope.

Earliest form of Terracing The field is supported by walls constructed across a narrow valley, which were originally occupied by an intermittent stream. The agricultural areas of these territories are usually level allowing water to drain into the reservoirs from around the surrounding slopes. The terrace’s effectiveness, durability and design suggests that this was the earliest form of terracing in the New World.

Types of Terraces Bench terraces Contour terraces Parallel terraces

Bench Terraces A shelf-like embankment of earth, usually man-made, along a contour of sloping land to control runoff and erosion Bench terraces reduce land slope and allow run-off from the upper side of the terrace to go into a lower portion where it spreads out and infiltrates.

Contour Terraces Contour terraces with their point rows and grassed waterway outlets, that follow the lay-of-the-land. contour terraces may have level channels to collect and hold the water until it seeps into the soil.

contour terrace system with many point rows and grassed waterways

Parallel Terraces parallel terraces are constructed parallel to each other. Parallel terraces eliminate the production losses associated with point rows and minimize interference to farming operations when spaced at multiple widths of planting and harvesting equipment.

A parallel terrace system.

Parallel tile outlet terraces Terraces that are constructed in parallel and discharging runoff through subsurface drains are known as parallel tile outlet terraces. With PTO terraces, water that accumulates behind a terrace ridge is discharged through a surface inlet into a subsurface drain. The surface inlet, called a riser, has a restricted section to control the discharge rate, causing some of the runoff to be temporarily stored.

Water temporarily stored behind a newly constructed PTO terrace.

Benefits of parallel tile outlet terraces. The total area can be farmed, since grassed waterways are not needed. Peak discharges are reduced because runoff is temporarily stored. Sediment and other contaminants settle out behind the terrace ridge before polluting water in a receiving stream.

Benefits of Terrace System. Conservation of soil and water. Reduces the velocity of water. Reduces soil erosion. Increases the infiltration.

Terraces in controlling erosion. They intercept rainfall runoff as it starts down a slope, thus preventing a large accumulation of flow on the surface. This reduces the potential for sheet and rill erosion. Terraces also give soil particles that do erode a chance to settle out in the basin behind the terrace ridge, while the excess water is slowly discharged through a subsurface drain.

Terraces interfere with field operations. Any permanently-installed practice will, to some degree, obstruct field operations and/or take some land out of production. However, these obstructions are greatly minimized under present methods of design. For instance, with a PTO terrace system, elimination of the grassed waterways more than offsets the interference caused by cross-slope ridges and channels.

What field conditions terraces are best adapted. Fields with long, fairly-uniform slopes that are not too steep (generally less than 8 percent) are best adapted to broad-based terraces. If the slopes are very irregular or if the soil is shallow (less than 6 inches), alternative method should probably be used.

In some cases, on land where a total terrace system is not practical, terraces are sometimes placed across minor watercourses. This type of terrace uses subsurface outlets similar to PTO terraces. It controls sediment discharge but does not check soil erosion as effectively, since steep slopes are likely to exist above the terrace.

BENCHING (BENCH TERRACES)

BENCHING It is converting a steep slop into a series of steps with horizontal or nearly horizontal ledge and vertical or almost vertical wall b/w ledges. It is also called bench terrcing.

Bench terraces In various parts of the world bench terraces have been extensively constructed at great expenditure of labor in order to make stabilize sloping land. Such structures consist nearly level benches that cross slope in the series of step like platforms.

History The practice bench terracing is almost as old as agriculture itself. Centuries before people attained great skill in the construction of essentially level terraces that were supported by artificial walls of stone. This structures were used extensively in the building of broad field in the valleys and establishing bench like strip on the mountain

Objectives Reduce the run off. Increase the infiltration rate. Conserve the soil

Keep in mind Before bench terraces are constructed in any area, a thorough study should be made to justify that soil is favorable for cultivation. There are many parts of the world where bench terracing undoubtedly is going to be required sooner or later because the scarcity of favorable land.

To hold a vertical face of some structural walls is necessary usually of stones or less frequently bricks of timber In stable soils this wall may be hold by vegetation. Large amount of labors required to construction of bench terracing

Bench terraces design to Control the erosion by reducing the slop of the cultivated areas. Make steep land available for cultivation. To reduce the run off and increases the infiltration.

Bench terraces are constructed on a contour, to minimize run off. The difficulty is to discharge any surface run off down slop without causing erosion. When bench terraces are uses to cultivate crop, It is desirable for each bench to be wide as possible

Step terraces When regular cultivation is not required, as for tree crops, smaller bench terraces will be effectively and less earth moving, these are called step terraces and used for tree,tea,coffee and wines.

Irrigation bench terraces Some time flat bench terraces raised lip at the outer edge to retaine irrigation water. Extensively used for production of rice. The Banaue rice terraces in Philippines are magnificent example of irrigation bench. It also found mostly in Indonesia, China and Japan because their staple food is rice.

STRIP CROPPING Crop planting in which wide rows of heavy-rooted plants are alternated with loose-rooted plants so as to lessen erosion, as on a hillside

INTRODUCTION Strip cropping is a very effective and inexpensive method for controlling soil erosion. Strip cropping is a combination of contouring and crop rotation in which alternate strips of row crops and soil conserving crops (sods) are grown on the same slope, perpendicular to the wind or water flow. When soil is detached from the row crops by the forces of wind or water, the dense soil conserving crops trap some of the soil particles and reduce wind translation and/or runoff

TYPES OF STRIP CROPPING Contour strip cropping Wind strip cropping Permanent or temporary buffer strip cropping

COUNTER STRIP CROPPING Contour strip cropping is the growing of a soil-exposing and erosion-permitting crop in strips of suitable widths across the slopes on contour, alternating with strip of soil-protecting and erosion-resisting crop.

WIND STRIP It consists of planting tall-growing crops such as jowar, bajra or maize, and low-growing crop in alternately arranged straight and long, but relatively narrow, parallel strips laid out right across the direction of the prevailing wind regardless of the contour.

Evaluating Fields for Strip Cropping Each field should be evaluated to determine three factors: 1)Which crops can suitably be grown on the field's soils- -This largely depends on the depth of the rooting zone .

THREE FACTORS 2)The most effective surface water management system for the field-gully erosion can be prevented by establishing sod-based waterways in the naturally-occurring major drainage channels running down slopes of the field. Using practices such as surface residue management, minimum tillage or no-till, winter cover crops, and crop rotations, in addition to establishing strips, will reduce the risk of rill and sheet erosion.

THREE FACTORS 3)The specifications for strips to be used on the field . Provide technical help in laying out strips to keep them of constant width. Along the field contour.

Establishing Cropping Systems in Strips Each strip should be viewed as a small, individual field, since many management decisions will be made on each strip or on groups of strips. Which crop rotation to use is probably the most basic of these decisions, since strip cropping will most likely involve growing at least two crops in some form of rotation among the strips. Although there are numerous possibilities for cropping systems, the following ones are the most common:

PROBLEM OF STRIP CROPPING One of the most common problems encountered in strip cropping is maintenance of sod waterways. Care must be taken when applying herbicides to cut spray nozzles or spreaders off each time you go across a waterway. Otherwise, sod will likely be killed and have to be reestablished

MULCHING

MULCHING: It is protective cover provided to soil by tillage practices, grasses, crop residues or any other material, which is termed as mulch and this practice is known as mulching.

OBJECTIVES: 1-To reduce runoff and soil losses OBJECTIVES: 1-To reduce runoff and soil losses. 2-To suppress weeds and save labour cost. 3-To reduce evaporation losses. 4-To adjust soil temperature. 5-To increase soil organic matter. 6-To decrease direct impact of raindrop onto soil surface.

Types of Mulches: (1)Natural Mulch (2)Artificial Mulch (1)Natural Mulch: It is provided by tillage operation. crumb structure is made, capillary tubes are broken down.capillary pores are decreased. Upward rise of water is checked.

(2) Artificial Mulch: Materials like manures, straw, leaves, stubbles, special papers are used as an artificial mulch.

Sources of mulches: -Cover crops -Grasses -Litter -Fibrous material -Cotton netting -Paper netting -Polythene sheats

Problems of mulch tillage: -Anaerobic conditions in wet areas Problems of mulch tillage: -Anaerobic conditions in wet areas. -Nutrient movement. -Soil surface temperature. -Introduction of pest, pathogen. attack or disease problem. -May cause toxicity. -Not effective in poor drained areas. -Problems in weed control.

Solutions to overcome these problems: -To control pathogen infestation strip zone tillage can be used, it reduces wind and water erosion. -Chiesling instead of ploughing. -Adequate drainage is required.

Effects of mulching: PHYSICAL EFFECTS: -Direct impact of rainfall Effects of mulching: PHYSICAL EFFECTS: -Direct impact of rainfall. -Splash erosion decreases. -Less depressions on surface soil. -Frequent freezing of soil. -Less accumulation of ice and water. -Decrease depth of frost penetration. -Aggregation of soil increases.

PHYSICAL EFFECTS: -Resistance to detachment by wind & water erosion PHYSICAL EFFECTS: -Resistance to detachment by wind & water erosion. -Increase porosity and water holding capacity. -Increase percolation & infiltration. -Decrease runoff & evaporation. -Decrease wind velocity.

CHEMICAL EFFECTS: -Tie up of available N. -Reduction of surface soil CHEMICAL EFFECTS: -Tie up of available N. -Reduction of surface soil. - Affect the release of N. -Increase N fixation. -Increase of total potash but less availability. -Loss of nutrients by leaching.

BIOLOGICAL EFFECTS: -Increase microbial activity BIOLOGICAL EFFECTS: -Increase microbial activity. -Larger population of insects,pathogen,rodents,pests. -Biological control measures can be used.

Watershed Management

Introduction Watershed “ is the land from which water drains into a particular stream, river, lake or other water body.” All land (and all humans, wildlife, and activity on that land) are part of one watershed or another.

Watershed Management Watershed Management “is land management and restoration as it is about the river itself. Protecting and restoring rivers entails addressing pollution and wildlife habitat problems in the entire watershed, or the entire land area that drains to the river.”

Principles of Watershed Management Utilizing the land based on its capability. Protecting top fertile soils Minimizing silting up of tanks,reserviors and lower fertile land In situ conservation of rain water Protecting vegetative cover throughout the year Water harvesting for supplemental irrigation Maximizing form income Improving infrastructural facilities for storage ,transport and Agri.marketing.

Objectives of Watershed Management Efficient use of land Flood control Adequate water supply Efficient use of natural resources Expansion of recreation facility

Steps in Watershed Management Basic Information Statistics of population and livestock Pattern of land ownership Topography Cropping System and Yield and land capability for farmer Data on Rainfall, Erosion problems and ground water Information on existing water resources Service faculties like school, banks ,Market health,Veternary facilities

Developmental Components Soil Conservation Measures Runoff Harvest in storage structures and its recycling for protective irrigation. Improving fuel, fodder and horticulture through alternate land use systems Optimal land use with appropriate technology Ground water recharge and development Efficient use of available water Development of livesotck,poltry and other associated activities

Component of Watershed Management Programme Soils and Water conservation Water Harvesting Crop management Alternate land use system