Club of bologna proceedings

Conservation Tillage in the U.S. 
(1998 update) 
 
For the first time ever, U.S. farmers are planting 
more area to crops using conservation tillage 
methods than traditional methods that rely on the 
plow or intensive tillage. Conservation tillage is 
defined as tillage practices that leave 30% or 
more of the crop residue on the surface after 
planting. Intensive (conventional) tillage are 
practices that leave less than 15% of the crop 
residue. Reduced-till will leave 15-30% of the 
crop residue after planting is completed. The 
1997 National Crop Residue Management 
Survey (
Fig. 1
) showed a 6 million acre (2.4 
million hectares) gain for conservation techniques. 
Traditional intensive tillage techniques declined by 
4 million acres (1.6 million hectares) in 1997. The 
survey results indicated that the conservation 
tillage systems, no-till, mulch-till, and ridge-till 
accounted for 109.8 million acres (44.4 million 
hectares) or 37% of the 294.6 million acres of 
cropland. The intensive tillage accounted for 
107.6 million acres (43.6 million hectares) and 
reduced-till accounted for the rest, 77.3 million 
acres (31.3 million hectares). 
No-till is done in soil that is undisturbed prior to 
planting. Planting is completed in a narrow 
seedbed approximately 1-3 inches wide (25-74 
mm). Weed control is done primarily with 
herbicides. In ridge-till the soil is left undisturbed 
prior to planting, but approximately one-third of 
the soil surface is tilled at planting with sweeps or 
row cleaners. Planting is completed on ridges 
usually 4-6 inches (100-150 mm) higher than the 
row middles. Herbicides and cultivation are used 
for weed control. In strip-till the soil is again left 
undisturbed prior to planting. Approximately 
one-third of the surface is tilled at planting, but 

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without the ridges. Tillage in the row may consist 
of rototilling, in-row chisel, row cleaners, etc. In 
mulch-till the total soil surface is disturbed by 
tillage prior to planting. Tillage tools such as 
chisels, field cultivators, discs, sweeps, or blades 
are used. Weed control is accomplished with a 
combination of herbicides and cultivation. 
The 1985 and 1990 Farm Bills in the U.S. 
require a conservation compliance plan on highly 
erodible lands if a producer wants to remain 
eligible for federal farm programs. There are 
many advantages of conservation tillage. 
Reduced contamination of surface and ground 
water supplies by soil particles, nutrients and 
pesticides is one of the primary advantages. 
Reduced equipment and fuel costs can be 
achieved, along with time and labor savings. Soil 
structure, water infiltration rates and water 
holding capacity will improve. Soil compaction is 
generally reduced due to reduced traffic on the 
cropland. Double-cropping (two crops in one 
growing season) is possible with conservation 
tillage methods. The most recent Farm Bill is not 
as rigid in requiring the farmer to meet 
conservation compliance requirements in order to 
qualify for subsidy payments and other farm 
programs. This is likely to cause farmers to 
return to intensive farming practices which will 
cause more soil erosion and therefore reduced 
water quality. 
The crops that are suitable for conservation 
tillage include: corn, soybeans, cotton, grain 
sorghum, sunflowers, peanuts, small grains and 
certain vegetable crops. Special planters have 
been developed for row crops and small grains. 
The current trend is to narrower rows for 
soybeans and corn, down to 7.5 inch (190 mm) 
row spacing. This means that herbicides are used 
for weed control and not cultivation. 
There is a non-profit organization, Conservation 
Technology Information Center (CTIC) which 
was established in 1982. This center is an 
agricultural based information and data transfer 
center. Its members and partners include 
individuals, corporations, government agencies, 
associations, foundations, universities and media. 
It promotes the use of conservation techniques to 
protect the soil, air and water quality of the U.S. 
It maintains a web site that provides information 
on the trends and adoption of conservation tillage 
practices for each state in the U.S. by crop. The 
web site also provides summaries of information 
on the activities of the center and publications 
that are available. The web site is
 
The most recent survey (1998) of CTIC on the 
use of conservation tillage in the U.S. is in