Land and Watershed Management - Practices of Irrigation and On-farm Water Management - page 203

efficiency will inevitably be low, there is no justification in achieving more than a
smoothing of the land in the direction of the slope.
In deciding whether or not to make the investment in precision grading of
agricultural fields on a farm, certain cost factors should be considered. The first
consideration is whether the producer should purchase the laser leveling and dirt
moving equipment and do the work himself or whether the work be hired out to
someone else on a custom-hired basis. The second cost consideration is determin-
ing how many years of crop production will be required to recover the investment
in precision grading costs.
The total amount of acreage on the farm to be leveled is a critical component in
this decision of whether to invest in precision grading equipment. If only a small
amount of acreage is planned to be graded, for example 50 ha, the producer may
choose to hire out the work rather than purchase the equipment for such a small
amount of acreage. However, if a large amount of acreage is to be graded over a
multiyear period, for example 300 ha graded over a 5-year period, it would probably
be more economical for the producer to purchase the laser leveling and dirt moving
equipment and perform the work himself.
The number of years of crop production required to recover investment in pre-
cision grading costs can be estimated by comparing the precision grading costs per
hectare with the increased net returns per hectare resulting from increased produc-
tion or the reduction in cultivation, irrigation, and other production costs resulting
from increased field efficiency. An estimate of the number of years required to
recover precision grading costs can be determined by dividing the precision grading
costs per hectare by the increased annual net returns per hectare.

6.4.4 Activities and Design Considerations in Land Grading

A grading plan should be prepared that establishes and includes the following:

•

Identification of areas of the site to be graded

•

An estimate of the land grading requirements

• How drainage patterns will be directed

• How runoff velocities will affect receiving waters

• Information regarding when earthwork will start and stop

• The degree and length of finished slopes

• Where and how excess material will be disposed of (or where borrow materials

will be obtained if needed)

• Berms, diversions, and other storm water practices that require excavation and

filling should be incorporated into the grading plan.

Before grading activities begin, decisions must be made regarding the steepness
of cut- and fill-slopes and how the slopes will be protected from runoff, stabilized
and maintained.