All SCS programs and services are offered on a non-
discriminatory basis, without regard to race, color,
national origin, religion, sex, age, marital status, or
handicap.

Supersedes Farming Terraced Land, Leaflet 335
Reprinted Apri! 1980

May 1987
Reviewed and approved for reprinting June 1990.



Maintaining Vegetation

Grassed back slopes and grassed narrow-base ter-
race slopes are critical areas. Establish and keep a
good sod, Initially, fertilize the vegetated areas with
the same amounts required to grow a good crop, such
as corn. Follow up with maintenance applications.
Control tree and brush growth by spraying or mowing,
if possible. Prevent burrowing rodents from inhabiting
the slope. Manage grassed waterways for hay produc-
tion, or mow two or three times each year. Correlate
mowing with bird nesting requirements. Protect
against herbicide damage and tillage implements

(fig. 15).

Maintaining Terraces

The first step in maintaining terraces is to prevent a
need for sediment maintenance. This is done by con-
trolling erosion in the interval between terraces. The
most effective approaches are residue management,
conservation tillage, and rotations (fig. 16).

Figure 15

Figure 16


There are several types of terraces. The three most
commonly used are broad-base, grassed back-slope, original
and narrow-base terraces (fig. A). Other terrace ground surface
shapes used are the flat channel, or conservation
bench terrace; the sediment control basin; and a com-
bination of shapes. Suitable outlets include grassed
waterways or underground pipes. On soils that have
high infiltration rates, terraces are built level. Outlets
are usually not needed for these level terraces.

w
cut slope front slope | back slope

Broad-base terrace cross section

original
ground surface

max 2:1 slope, 0.2 percent
should be grassed min slope

Steep back-slope terrace cross section

original max 3:1
ground surface slope

max 2:1 slope

Narrow-base terrace cross section

Figure A




Farming Terraced Land

You can often improve the farmability of the field and
access by farm equipment by properly planning and
constructing your terraces. A planned field border or a
field road system, for example, can provide access to
the field (fig. 10).

Where terraces are parallel, there is little trouble with
farming. If terraces are not the same length, start all
operations from the longest terrace (key terrace) to
the shorter ones. Start all operations from the front
slope of the key terrace (fig. 11).

Where possible, construct terraces parallel to each
other; however, if terraces are not parallel, keep the
correction area near the center between the terraces.
This will eliminate turning on the terrace. You may also
leave correction areas in sod instead of planting row
crops. Although correction areas make up a small part
of the field, they may cause the most problems during
farming operations.

Figure 10

Figure 11


Narrow-base — Both front and back slopes of these
terraces are steep, seeded to permanent vegetative
cover, and not farmed. During terrace construction,
soil is usually pushed up from the downhill side. Much
less soil is required to build these terraces than for the
other types mentioned (fig. 5).

Special treatment should be given to the disturbed
areas where soil has been taken to build the terraces.
It may include additional liming, fertilizing, and ripping.
Many of these disturbed areas need the topsoil re-
placed after construction or repair of terraces (fig. 6).

Figure 5

Figure 6


Broad-base — All slopes of broad-base terraces are
farmed, so they are designed to fit machinery needs.
For best farmability, terrace spacing and the length of
both front and back slopes should be multiples of the
machine width. Don't straddle or cross terrace ridges
with farm equipment. Move between terraces on
planned field roads or grassed areas (fig. 3).

Grassed back-slope — The back slope is not farmed
but seeded to permanent vegetative cover. Most of
the soil used to build these terraces has been taken
from the downhill side, resulting in a benching effect
and some flattening of a part of the slope to be farmed

(fig. 4).

Figure 4




Contour Stripcropping and Rotations

Where you choose to grow small grains and forages,
you may widen and farm the spaces between the ter-
races. Plant alternating strips of row crops, meadow,
and small grains (fig. 8). You may also use conserva-

tion tillage in the strips.

On the vegetated slopes, seed and manage desirable
grasses and legumes suitable for wildlife nesting and
cover (fig. 9).

Figure 8

Figure 9


United States
Department of
Agriculture

Soil
Conservation
Service

Leaflet Number 570

Farming and
Maintaining Terraces



Grassed Back-Slope and Narrow-Base Terraces
Begin all farming operations on parallel terraces on the
front slope and work uphill to the base of the upper
terrace. Farming with correction areas will be the
same as on broad-base terraces. Avoid crowding veg-
etated areas, and protect them from herbicide damage
and tillage equipment (fig. 12).

10

Figure 12


Broad-Base Terraces
Step 1. Plant on the inside slope of the top terrace up
to the top of the slope or field boundary (fig. B).

Step 2. Plant down on the back slope of the top ter-
race to a point about half the distance between the
top terrace and the one with the correction areas
(fig. C).

Step 3, Plant from the key terrace of the lower parallel
system up to the rows already planted. The correction
area remaining near the center between the terraces
can be planted from either side of the uneven area.
Use the last terrace as a guideline to plant to the bot-
tom of the field (fig. D).

Step 4. Follow the same procedure for additional
tillage operations and harvesting.

Figure B

Figure C

Figure D


Related Conservation Practices

Conservation Tillage

Conservation tillage, which leaves all or a portion of
the previous crops’ residue on the soil surface after
planting, is compatible with virtually all cropland con-
servation practices. Its use reduces erosion by 50 to
90 percent, as compared to conventional tillage,
depending on the amount of residue left on the soil
surface.

Combining conservation tillage and terraces can be an
effective conservation system. Conservation tillage will
reduce soil movement between terraces, which will
lessen routine maintenance costs, while terraces
shorten the length of the slope and control soil dam-
age caused by concentrated water flow. If water con-
servation is your primary concern, terraces and
conservation tillage will again work well together. Con-
servation tillage will stow water runoff, which will
increase infiltration, and the terraces will keep surface
flow from leaving the field.

There are basically four types of conservation tillage:
no-till, ridge-till, strip-till, and mulch-till. For more infor-
mation and technical assistance on these types of
conservation tillage, contact your soil and water con-
servation district.

Contouring

Contouring between terraces is most effective in
reducing erosion where outer rows are somewhat
higher than middle rows as a result of cultivating for
weed control (fig. 7).

Figure 7


Introduction

Terrace systems, in combination with other conserva-
tion practices, are used to help solve erosion and
other resource problems. In addition to their esthetic
appeal and promise of land stewardship, terraces can
be the backbone of a cropping and water manage-
ment system. How well terraces do their job of pro-
tecting cropland depends on how they are farmed and
maintained.

Good management — which includes such practices
as conservation tillage; proper methods of planting,
fertilizing, and rotating crops; crop residue use; and
controlling pests — is essential for the efficient produc-
tion of healthy and vigorous crops (fig. 1). It is also
important to soil and water conservation because it
ensures production of adequate amounts of crop resi-
due for erosion control.

The main function of terraces is to control and man-
age runoff, especially in the concentrated flow areas.
This helps reduce gully erosion and conserves
moisture. In some cases, terraces may also shorten
the slope length exposed to overland flow, the area
where sheet and rill erosion occurs. Modern terrace
systems are mostly parallel. They are easier to farm
and maintain.

Terraces are one of a number of conservation prac-
tices used to reduce erosion. In most cases, one or
more additional conservation practices are used with
terraces to complete a conservation system (fig. 2).

Conservation tillage, contouring, and grassed water-
ways are conservation practices commonly used with
terraces. These supporting practices are necessary to
maintain terraces.

Figure 1

Figure 2



The terraces’ capacity to hold or channel water must
be maintained. If low spots develop in ridges, repair
the problem spots. When sediment does accumulate
in channels, remove it by mechanical means and con-
sider redistribution upslope (fig. 17).

Moldboard plowing between terraces is not recom-
mended. Plowing increases sheet and rill erosion, with
aresulting increase in sediment in the terrace channel.
Dead furrows between terraces can also cause
problems.

Use conservation tillage between terraces. This could
range from using no-till to some other form of conser-
vation tillage. Keep crop residues on the surface, as
discussed previously in the section on conservation
tillage. Always farm with the terrace system and never
across it. This eliminates wearing down the terrace
ridges (fig. 18).

Figure 17

Figure 18

13


Step 4. Till the uniform-width turnstrip (fig. H).

The terrace ridge height is critical to maintaining ade-
quate capacity and protecting lower terraces. Quickly
repair any damages to the terrace ridge.

Effective erosion control and resource conservation
require that both management and structural practices
are coordinated in a complete soil and water conserva-
tion system. How well terraces do theif job as part of
this system depends on how you farm and maintain
them (fig. 19).

Figure H

Figure 19



Farming and Maintaining Terraces

Contents

List of figures . a1
Introduction ..............-..5- 2
Related conservation practices

Conservation tillage ........ 2.2. eee eee ee 6
Contouring 6
Contour stripcropping and rotations . . . -7
Farming terraced land

Broad-base terraces ... .9
Grassed back-slope and narrow-base terraces 10
Maintenance

Underground outlet system . . ani
Grassed waterways ... . -A1
Maintaining vegetation . . 12
Maintaining terraces ... 12
Grassed back-slope and narrow-base terraces 14

List of Figures

1. Terrace systems depend on good management 2
2. Terraces are part of a complete conservation
system .
Common types of terraces .
Broad-base terraces in cropland
Grassed back-slope terraces in cropland
Narrow-base terraces in cropland ...........
Terrace construction and treatment of disturbed
APEAS. oe eee
7. Cultivating terraced cropland.
8. Terraces with contour stripcropping.
9. Grassed back-slope terraces planted for wildlife

nesting and cover... 2.0.0... 06 ce eevee
10. Terraced cropland showing field border
11. Parallel terraces on irregularly shaped field .
B. Step 1.
C. Step 2.
D. Step3. ..
12. Cultivating a grassed back: slope terrace .
13. Pipe inlet with a large quantity of sediment .
14. Grassed waterway with equipment damage
15. Well-vegetated back-slope terrace ....... :
16. Cover crop on grassed back-slope terrace ....
17. Sediment cleanout ..... os
18. No-till planting on terraces . .
E through H. Steps 1 through 4.
19. Terraces can be an integral part of the

landscape ........ 6... 60.2 cece eee 15

OAR oD





Maintenance

A good maintenance program will help assure long life
and continued benefits from a terrace system.

Underground Outlet System

Periodically check underground outlets, animal
guards, and tile inlets. Remove debris and sediment
when necessary. Be careful that farming operations
do not build ridges around inlet pipes. The ridges
could block complete drainage of the terrace channel.
If tile blowouts or other damages occur, make repairs
immediately (fig. 13).

To protect inlets from damage by equipment, live-
stock, and wildlife, use high-visibility paint and risers.
Fence around risers where livestock are present. Con-
trol tall grasses and weeds around the inlet. If wetness
occurs in the terrace channel, install drains.

Grassed Waterways

The most common causes of waterway failure are
abuse and neglect. Careless crossing with farm imple-
ments can severely disrupt areas of sod. Using the
waterway as a field road leads to the development of
bare areas that are vulnerable to erosion (fig. 14). If
you must occasionally use the waterway as a road,
travel along the edge, not down the center. At all
times, maintain your waterway so that it supports the
other conservation practices.

Figure 13

Figure 14

1


Grassed Back-Slope and Narrow-Base Terraces
Begin all tillage and planting operations on the front
slope of the terrace or at the toe of the front slope of
the narrow-base terrace, and plant upslope to the next
terrace.

Step 1. On parallel broad-base terraces, begin tillage
and planting operations at the terrace ridge and pro-
ceed both upslope and downslope until you have cov-
ered about one-third of the area between the terrace
ridges. Do this on each terrace; then work out the re-
maining areas between the terraces (fig. E). ©

Step 2. When farming nonparalle! terrace systems,
begin all tillage and planting operations at the terrace
and work both upslope and downslope from the ter-
race. This leaves all short rows near the middle of the
terrace spacings. Before beginning the short rows, be
sure there are sufficient end rows between the terrace
and the beginning of the short rows to turn on without
causing damage to the terraces or to the equipment
(fig. F).

Step 3. Till extra rounds on the wide parts of the
remaining area until you have an even turnstrip ex-
tending the entire length of the field. This allows tillage
of the irregular areas without turning on the tilled
ground (fig. G).

14

Figure E

Figure F

Figure G