### **ITEM T‑907  TILLING**

DESCRIPTION

**907‑1.1**   This item shall consist of preparing the surface of areas
for dust control or erosion control in accordance with this
specification at the locations shown on the plans or as directed by the
Engineer.

CONSTRUCTION METHODS

**907‑3.1  GENERAL.**  Areas to be tilled and areas requiring special
attention and tilling shall be shown on the plans.

The tilling work shall be performed only during periods when beneficial
and satisfactory results can be reasonably expected.  The work shall be
stopped when it is unlikely that the desired results will be obtained,
due to excessive drought, moisture conditions, or other factors, and
resumed only when the conditions again are favorable.

Suitable equipment necessary for proper tilling and for handling all
required materials shall be on hand, in good operating condition, and
approved by the Engineer before the various operations are started.

**907-3.2 TILLING.**

**a. General.**  Prior to the commencement of tilling operations, all
heavy growths of vegetation on areas shown on the plans to be tilled
shall be mowed, raked and burned, used for mulch if suitable, or hauled
off the site, as directed by the Engineer.

During tilling operations, the ground surface shall be kept cleared of
all cable, wire, or any other waste materials that might hinder final
grading, planting, or subsequent maintenance operations.  Any
irregularities in the surface resulting from tilling or other operations
of the Contractor shall be corrected insofar as practical to prevent the
formation of low places and pockets where water will stand.

The proper graded areas shall be tilled by the Contractor with suitable
plows, discs, scarifying machines, or other power‑drawn implements
approved by the Engineer.

**b. For Dust and Erosion Control.**  The areas to be tilled for dust or
erosion control shall be loosened to a depth of at least 4 inches (10
cm) by a tiller tool so that clods will be left on the surface of the
ground.  In areas where such penetration cannot be accomplished by a
tiller tool in one operation, a heavy scarifier shall be used first.  On
areas 250 feet (76 m) or more from the centerline of runways, as shown
on the plans, on which scarifiers will not produce clods of sufficient
size and quantity to provide adequate control by the above operation,
furrows shall be opened on approximately 36‑inch (90 cm) centers to a
depth of 5 inches (12 cm) by using an approved type lister.  Tilling
operations shall commence on the windward side of the field and at right
angles to the prevailing wind except on runway shoulders, where they
shall be parallel to the pavements.  Equipment and operations, other
than those specified above, may be used subject to the approval of the
Engineer.

**907-3.3 SMOOTH GRADING.**  Where final grades have been established by
others, they shall be shown on the plans.  Where grades have not been
established, the areas shall be smooth graded and the surfaces left at
the prescribed grades in an even and properly compacted condition which,
insofar as practical, will prevent the formation of low places and
pockets where water will stand.

METHOD OF MEASUREMENT

**907-4.1**  Tilling shall be measured by the number of acres (square
meter), measured by surface area, tilled, smooth graded, and accepted.

BASIS OF PAYMENT

**907-5.1**  Payment will be made at the contract unit price per acre
(square meter) for tilling.  This price shall be full compensation for
furnishing all materials and for all preparation, operation and smooth
grading, and for all labor, equipment, tools and incidentals necessary
to complete the item.

Payment will be made under:

Item T‑907‑5.1 Tilling---per acre (square meter)

**END OF ITEM T-907**