|
Items in cart [0] |
Questions? Call 888-624-8373 |
| Copyright © 2009. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 308
CASE STUDY
Crop-Livestock Farming in Iowa
The Thompson Farm
RICHARD AND SHARON THOMPSON S FARM is in eastern Boone County,
Iowa, at an elevation of about 1,000 feet. It is located in Jackson
Township on sections 16, 17, and 21, which is about ~ miles west of Ames
and 4 miles clue north of the Iowa State University Agronomy and Agricul-
tural Engineering Research Center. The farm has a total of 300 acres, all of
it owned by the Thompsons and all of it tillable. Of this total, 232 acres are
tilled, which is about the average farm size for the state of Iowa as a whole
and for Boone County.
GENERAL DATA
The Thompsons have a diversified farming operation, which is no longer
the norm in their area (Table 1~. Statewide, about 55 percent of farmland is
used to grow corn each year, and roughly one-third of the lane! area is
devotecl to soybeans. For Boone County, the corresponding figures are 40
percent (127,000 acres) and 35 percent (117,000 acres), respectively, propor-
tions that are typical of north-central and central Iowa. There are only
11,000 acres of oats and 9,000 acres of hay in the county. The most common
crop sequence in the vicinity is corn-soybeans-corn-soybeans. The Thomp-
sons grow corn on 33 percent of their land and soybeans on 15 percent, on
average. Specifically, the farm grows approximately 100 acres of hybric! field
corn, 50 acres of soybeans, 50 acres of oats, and 50 acres of hay; another 32
acres are in pasture. The Thompsons keep 50 cows in the foundation herd
ant! raise the calves through finishing; the farrow-to-finish hog operation
has 90 sows.
Dick Thompson received an M.S. degree in animal production from Iowa
State in the 1950s and started farming conventionally. For a 16-year period
308
OCR for page 309
THE THOMPSON FARM
TABLE 1 Summary of Enterprise Data for the Thompson Farm
Category
309
Description
F.
arm size
Labor and
282 acres of tilled cropland, 50 cows, 90 sows
The farm's diversified operation spreads labor requirements
management throughout the year. It is managed and operated by Dick and
practices Sharon Thompson and their son, with one full-time hired man
who takes care of the swine. Dick Thompson spends
considerable time doing on-farm research.
The farm has a 50-cow foundation herd of cattle (Angus-Hereford
cows and exotic breeds of bulls); it also has a 90-sow, farrow-to-
Livestock management
practices
finish hog operation (1,300-1,400 pigs finished/year).
Marketing strategies Most crops and livestock are sold through ordinary commercial
markets with no price differential for methods of production.
The exception is about 15 percent of beef animals, which are
sold directly to individuals at a $0.10/pound premium, less the
transportation cost to the locker/slaughter plant.
Weed control practices Ridge tillage and high plant populations, in conjunction with crop
rotation and cultivation with rotary hoe, disk billers, and
sweeps, are used. Small grains in the rotation disrupt weed
reproductive cycles. If rain delays cultivation and weeds threaten
crops, postemergence herbicides will be used.
Insect and nematode No particular pest problems were reported. Crop rotations and
control practices ridge tillage, plus a diversity of plant species, are credited for
this situation.
Disease control No antibiotics are used except to treat illness. Various measures
practices
Soil fertility
management
Irrigation practices
Crop and livestock
yields
are used to build resistance in the hog herd (for example,
probiotics, transfer of manure from farrowing units to gestation
pen). Cattle are not vaccinated. The farmer limes the pens to
keep the pH unfavorable to pathogens, and uses isolation,
sunlight, and special feed rations (for example, steamed rolled
oats) to prevent scours and other diseases.
Municipal sludge and manure (18 tons/acre) are applied to corn
and soybeans. Urea (30 pounds N) is applied to corn and oats at
planting; 30 pounds K2O is applied to corn and soybeans at
planting. The farmer uses 5- to 6-year rotations with corn,
soybeans, oats, meadow, and green manure in various
combinations.
None
Corn yields are 130-150 bushelslacre versus the county average of
124; soybeans, 45-55 bushels/acre versus 40; oats, 80-100
bushels/acre versus 67; hay, 4-5 tons/acre versus 3.4. Pigs are
finished and sold. The average number of pigs sold per sow is
14.4-15.6 versus an average of 14.8 for a group of 270 Iowa
Swine Enterprise Record members.
Financial performance Municipal sludge is provided free of charge; only a limited
number of farms can receive this free resource. Costs are kept
low by the use of on-farm resources, such as N2 fixation and
labor. Corn and soybean production costs are lower than for
conventional farms. Farm cash flow is adequate to meet
operating costs without borrowing, to maintain and enhance the
capital stock of machinery and facilities, and to support the farm
family.
OCR for page 310
310
ALTERNATIVE AGRICULTURE
(1967-1983), however, the farm was organic in the sense of using no pur-
chased fertilizer or herbicides. The only off-farm nutrient input to the sys-
tem during this time was through feed purchased for the livestock. More
recently, sewage sludge from nearby Boone (population 13,000) has been
used.
Thompson has always been an innovative farmer, and his operations
change to a greater or lesser extent from year to year. Because he is still
not satisfied with aD the procedures used on the farm, he conducts on-farm
research and demonstration trials involving tiliage, weed control, fertility,
rotations and cropping systems, cover crops and interseeding, hybrid and
variety comparisons, and livestock management.
Commodities Produced, Used, and Marketed
Soybean yields on the Thompson Farm are 45 to 55 bushels per acre; 7-
year county and state averages are 40 and 37 bushels per acre, respectively.
(The state and county data are from "Iowa Agricultural Statistics," compiled
and issued by the Iowa Crop and Livestock Reporting Service of the Iowa
Department of Agriculture. The published attainable mean yield for the
farm's best soils is 50 bushels per acre and 37 for the poorest.) All of the
soybeans are sold, thus far only through standard market channels.
Corn yields on the Thompson Farm are now in the range of 130 to 150
bushels per acre. County and state averages (1979-1985) are 124 and 115
bushels per acre, respectively, and the highest attainable yield figures are
150 bushels per acre on the best soil and 115 on the poorest. The grain is
fed to the livestock, supplying their needs for about 6 months out of the
year; the stalks are used for bedding the animals.
Oats generally yield 80 to 100 bushels per acre for the Thompsons (al-
though the yield was 127 bushels in 1985~. The 7-year county ant! state
averages are 67 and 62 bushels per acre, respectively. The oats are fed to
hogs, calves, and yearling feeder cattle.
Hay harvest (three cuttings) on the farm yields 4 to 5 tons per acre per
year. County and state averages from 1981 to 1985 were 3.4 and 3.3 tons per
acre, respectively. The hay is all fed.
Statewide, 1983 and 1984 were drought years in which yields of row crops
were severely depressed in some regions but not in central Iowa. The yields
that are given for the Thompson Farm apply to more nearly normal crop-
ping years. Also, the farming methods used by the Thompsons have been
evolving over time; these numbers represent what can be produced now
and not what the yields on the farm have been since 1979. Still, production
on the Thompson Farm compares well with that of the best conventional
farmers and the published attainable productivity of its soils.
The hogs produced on the farm are crossbreeds. Annually, the Thomp-
sons finish 1,300 to 1,400 pigs that are then sold through normal market
channels. Boars are purchased to match the sow herd, which is replenished
by keeping replacement gilts produced on the farm.
OCR for page 311
THE THOMPSON FARM
311
The cows are Black Baldies, an Angus-Hereford cross; the two bulls are
of mixed exotic European breeds. Replacement heifers and bulls are pur-
chased from herds known to be healthy. About four dozen cattle are fin-
ished each year. Of these, six to eight head are typically sold to individuals
on a carcass basis for a premium of $0.10 per pound. Transportation to the
locker comes out of this premium.
PHYSICAL AND CAPITAL RESOURCES
Soils
The landscape of the area is gently rolling, with slopes of up to 10 percent.
The soils are young mollisols clerived directly or indirectly from glacial till
of the Wisconsin glaciation, from which the ice receded only about 12,000
years ago. The farm is in the Clarion-Nicollet-Webster soil association area
and is typical of the swell-swale topography that constitutes over one-fifth
of the state. These soil types predominate and are very good to excellent
for crop production in Iowa. Subsoils are calcareous, and in poorly drained
parts of the farm the topsoils are calcareous also as a result of secondary
calcium carbonate deposition. The Canisteo, Okoboji, and Harps soil series
occur in such potentially wet places on the property. The soils are all loams
and clay loams and have relatively deep A horizons of 1 to 2 feet, with
organic matter contents now characteristically 2 to 6 percent. Clay accumu-
lations in the B horizons of the subsoil restrict internal drainage. Prior to
the installation of drainage tile, and in some places canals, this part of the
state was marshland.
Buildings and Facilities
Buildings and facilities on the farm include a building that contains a
machine shop. The ability to repair, modify, and construct equipment at
home is an important survival skill for any farm. In the case of the Thomp-
son Farm, such a capability is absolutely essential because of the amount
and kind of equipment needed for farming operations and the modifica-
tions created by the Thompsons.
A manure bunker 48-by-176-by-12 feet) is currently being constructed
and will be an important element in the improvement of manure handling
on the farm. The bunker will also receive municipal sludge from the city of
Boone; the farm used 270 dry tons in 1986 at 80 percent moisture. The
sludge contains 2.5 percent nitrogen and 1 percent phosphorus on a dry
basis and is monitored for chromium because of a tannery that contributes
to the Boone waste flow.
The Thompsons currently dry their corn on the ear. They plan to build
another crib, narrow and oriented to catch the winter winds, that they hope
will allow them to harvest ear corn at 25 percent moisture if necessary. In
addition, two metal grain bins (each with a 7,000-bushel capacity) have
OCR for page 312
312
ALTERNATIVE AGRICULTURE
recently been added, which will expand the farm's options for marketing
soybeans.
The hog operation uses a system of do-it-yourself insulated, prefabricated
units with open fronts that offers sunshine, fresh air, and isolation and
costs less than a confinement unit of comparable size. The farrowing isolits
cost $937.00 per unit for 30 units in 1979; a confinement building at the
time would have cost around $2,000 per unit. The nursery units cost $34.00
per head; an enclosed building would have required an investment of $80.00
per head. The Thompsons' finishing facility cost them $37.00 per head out-
of-pocket, compared with the cost of a building for the purpose at about
$145.00 per head.
Open-front housing requires a good windbreak to keep snowdrifts out of
the area. The farrowing isolits are equipped with both liquid propane infra-
red heaters and electric heat pumps. Two truck mud flaps are hung over
the lower part of the nursery doors in winter, stopping the wind but allow-
ing enough air circulation to prevent humidity build-up in the units. Nipple
waterers provide clean water on demand throughout the year.
Machinery
The Thompsons own three tractors. A 3-year-old tractor with 120 horse-
power and front-wheel assist is used with the manure spreader, the baler,
and the feed grinder and to pull the disk and cultivator. A 55-horsepower
tractor is also 3 years old; it has a front-end loader and is used to handle
manure, to mow and condition hay, and to cultivate. A 60-horsepower
tractor is at least 20 years old and is used for planting and cultivation. At
planting time, all three tractors are often in operation at once.
Other farm equipment includes a 14-ton-capacity manure spreader; a 30-
foot flexible rotary hoe; a heavy-duty offset disk; a stacker-baler, now used
only for corn stalks; a baler that makes large, round bates; a 12-foot wind-
rower-conditioner; a hay turner; an oat windrower; a grinder-mixer; a grain
drill; a 4-row ear corn picker; a 4-row combine for soybeans and oats; and
a water wagon for manure tea.
Climate
This grain-producing region is characterized by a continental climate with
cold, dry winters (December, January, and February) and a warm-to-hot,
humid growing season. Except for late July and early August the area's
average precipitation equals or exceeds the evapotranspiration of the pre-
dominant crops. The root zone of soils holds about 10 inches of plant-
available moisture. Even so, moisture stress is not uncommon, and major
drought years occur every 18 to 20 years.
The average length of the growing season is 189 days from April 14 to
October 20. The soil is usually warm enough to plant corn by the first week
of May, with soybeans generally planted around the micldle to the end of
OCR for page 313
THE THOMPSON FARM
TABLE 2 Normal Monthly Temperature and Precipitation at Boone, Iowa
313
Month
Normal
Temperature (OF)
Normal
Precipitation (inches)
January
February
March
April
May
June
July
August
September
October
November
December
Average annual
17.1
23.4
33.0
49.5
61.1
70.1
74.0
71.1
63.5
52.8
37.0
24.3
48.2
Average annual total
0.74
0.95
2.07
3.40
4.37
5.11
3.45
3.89
3.21
2.31
1.33
1.28
32.11
NOTE: The normal monthly temperature is the average of the normal daily maximum and
minimum temperatures for that month from 1941 to 1970. The normal monthly precipitation is the
average of the inches of precipitation for that month from 1941 to 1970.
SOURCE: National Oceanic and Atmospheric Administration. 1985. Climatological Data Annual
Summary—Iowa, 1985, Vol. 96, No. 13.
May. The average first frost (32°F) occurs around the first week of October.
The mean growing degree-day accumulation for the cropping season
through September is about 3,100 (50 to 86°F). Mean temperature and
precipitation for the region over the course of the year are shown in Table
2.
MANAGEMENT FEATURES
The current working philosophy of the Thompson Farm is to limit or find
substitutes for off-farm inputs wherever possible to reduce costs and pro-
mote the health of livestock and people. For example, herbicides and anti-
biotics are not routinely employed, although these inputs are used when a
crisis occurs, as in the case of treating a sick animal. Or, if there are thistles
in a pasture, the individual plants will be sprayed with herbicide. For the
most part, balance and diversity give the Thompsons' operation a certain
resilience, qualities that are manifest in, for example, the mix of species in
the pastures ant! in the gut of the livestock and in the early-season weeds
in the row crops.
Rotations
There are five outlying fields on the farm that use a 5-year rotation of
corn-soybeans-corn-oats-meadow. Manure and sludge are spread on these
fields just before they are planted with corn and soybeans. Four smaller
OCR for page 314
314
ALTERNATIVE AGRICULTURE
fields near the homestead that alternate as pastures use a 6-year rotation of
corn-soybeans-oats-meadow-meadow-meadow. Manure and sludge are ap-
plied prior to planting corn and soybeans on these four fields as well.
Clearly, raising animals is not an option for every farmer. Recognizing
this, and wishing to demonstrate other farming options, the Thompsons
have allocated land for two rotations that are relevant to the typical cash
grain operation. One is the corn-soybean rotation that is so common in the
Midwest; the other is a 3-year oats with green manure cover crop-corn-
soybean rotation. The Thompsons' purpose in these rotations is to investi-
gate alternative methods of production and show ways in which growers
with no manure or sludge can still limit production inputs purchased off
the farm.
Tillage and Planting Methods
Ridge tillage is a form of reduced or conservation tiliage used in the
Midwest that has gained some DoDularitv Darticulariv in areas with heavy
soils that warm slowly in spring. In this practice the new crop is planted
directly into the ridge remaining where the previous crop grew; no prior
working of the soil is needed to prepare a seedbed. Most ridge-tilIage
farmers plant on the top of the ridge and usually apply herbicide in a band
over the row. Since 1980, however, the Thompsons have planted on ridges
without using any herbicides at all.
In the Thompson modification of the standard ridge-tillage program, the
planter shaves off the top two inches of the ridge, throwing soil, weeds and
weed seeds, and cover crops into the middle or interrow zone. This method
accomplishes two things: it helps to incorporate the manure, which has
been applied just ahead of the planter, and it provides a planting strip in
soil that is unoxygenated and fairly free of weed seed and that has not been
exposed to sunlight. Weed seeds from the previous year may have fallen
onto the surface of the ridge, but these are thrown into the interrow zone.
In addition, the strip prepared for planting is in soil lacking the environ-
mental cues oxygen, light, and warmth that signal dormant weed seeds
to germinate.
Soybeans are planted at a rate of 12 seeds per foot of row instead of the 9
or 10 customarily recommended. The Thompsons use a tall, fast-emerging
variety, one of the benefits of which is that it quickly establishes a small
canopy over the row itself for within-row weed control. Weeds between the
rows are easily cultivated. The Thompsons also plant a tall corn hybrid at a
relatively high rate (24,000 to 26,000 plants per acre), again, to assist in
weed control.
The basic planting unit used by the Thompsons is a 4-row ridge-tilIage
planter, which is set up for 36-inch rows (planter costs are about $2,000 per
row). A number of alterations have been made, however, to adapt the
planter to this planting method. The two drive wheels were rotated to the
. . .. . .
OCR for page 315
THE THOMPSON FARM-
315
back of the planter, where they are less likely to pick up manure, and a soil
scraper was added to each. The sweep that cuts off the top of the ridge was
extended by 4 inches on each side to throw more soil into the middle. A
metal plate was added on the rear of the sweeps to extend them back to the
trash rods, and these rods are also covered with plates to keep soil and
weed seeds from falling back into the row. With these changes the planter
can be set deep enough to ensure a clean strip on the ridge for planting.
Flexible plastic hoses on the planter are mounted to deliver fertilizer from
tanks on the tractor. Disk openers enable this material to be placed 2 inches
below and 2 inches to the side of the seed; in addition, the planter shoe can
dispense starter fertilizer with the seed itself.
Every effort is made to rotary hoe all row crops at least twice, which is
another key element of the Thompsons' weed management strategy. The
depth of rotary hoeing can be controlled both by the three-point hitch and
by gauge wheels on the implement. The field is first hoed 3 or 4 days after
planting, before the crop emerges. The purpose of this hoeing is to turn up
tiny, germinating weeds while they are still in the vulnerable white root
stage. The second pass with the rotary hoe occurs about 7 days later, after
the crop has emerged. (The soybeans should be showing their first true
leaves.)
Crop losses as a result of hoeing are quite small; in most cases, only very
shallow penetration of the soil is required. The operator can drive through
the field at a brisk 10 to 12 miles per hour. The benefit to the crop in terms
of weed control is great. Thompson maintains that when he is able to rotary
hoe twice, his weed problems are well under control. With the 30-foot
rotary hoe, Thompson can cover 150 acres in a single day, minimizing the
system's vulnerability to changing weather conditions.
The 4-row cultivator costs about $1,200 per row. A mirror mounted low
and forward on the body of the tractor allows the driver to position the
cultivator precisely while still facing forward. Deep, adjustable shields ride
over the crop at any desired height, protecting young plants from clods
thrown by the cultivator and keeping weed seeds out of the row. The
cultivator is also equipped to deliver a side-dressing of fertilizer nitrogen,
although the Thompsons customarily apply fertilizer earlier in the season.
Herbicide boxes with rubber flights are used to dispense cover crop seed,
through more plastic tubing, to the row just ahead of the disk billers at the
last cultivation.
A pair of disk billers and a sweep are used in each interrow zone for the
first and second cultivation of soybeans. At the third and last cultivation,
only a sweep is used with a ridging V behind it to create a firm ridge for
the next year's crop. On the first two cultivations of corn the cultivator is
mounted with a set of disk billers and a sweep. On the last cultivation two
pairs of billers are used; they are turned to throw soil into the row, thus
rebuilding the ridges. When ridges are constructed at the last cultivation,
in late June or July, weed seeds have a chance to germinate and are then
OCR for page 316
316
ALTERNATIVE AGRICULTURE
choked out by the growing crop and limited moisture. Experience has
shown that in years when ridges cannot be made until late fall or the next
spring, the following row crop has more weeds.
Weed Control
The main element of weed control on the Thompson Farm is the use of
the modified ridge-tilIage planting and cultivation system just described. In
addition, the Thompsons choose varieties of soybeans and corn that are tall
and that do well at higher population levels. If, using the ridge system, the
weeds should exceed the economic threshold, Thompson would suggest
banding postemergence herbicide over the soybeans or corn. Thompson
believes that herbicide use helps select the particular weed species that
proliferate on a farm. Years ago, on an atrazine program with continuous
corn planting, his big problems were milkweed and ground cherry. He
maintains that the veIvetleaf (buttonweed) now so widespread in Iowa is a
product of the grass herbicides used in recent years.
The inclusion of small grains and hay in the rotation helps to disrupt the
weed cycle. The Thompsons value cover crops, such as rye, for their ability
to inhibit weeds directly. Whether this inhibition occurs through allelopathy,
direct competition, or a combination of the two, weec! populations appear
to be low or very low in fields in which rye is growing or has recently been
grown.
Some suggest that an herbicide-free weed control program can only suc-
ceed in operations in which there are cover crops and small grains in the
rotation to prevent the build-up of weed populations, particularly those of
perennials. An extended fielc! study on the farm has evaluated weed levels
in the bean years of a corn-soybean rotation under three weed control
systems: (1) ridge tilIage without herbicides; (2) ridge tiliage with the grass
herbicide metolachior broadcast before planting soybeans and corn; and (3)
conventional tilIage without herbicides.
The last of these treatments employs the method of weed control used
before the development of herbicides: several diskings performed at inter-
vals before planting to allow weed emergence followed by weed destruction.
The results indicate why herbicides are now considered indispensable by
many farmers. When it rains a lot, weed problems can be severe using this
system.
Weed infestation, over time, became worse in the conventional tilIage
treatment. Broadleaf weeds also increased in the ridge-tiliage-plus-meto-
lachIor treatment. (There was no statistical difference between the soybean
yields obtained in the two ridge-tiliage treatments, although yields in the
nonherbicide treatment tended to be a bushed or two higher.) Most impor-
tantly from the standpoint of the cash grain farmer, there was no increase
in weeds in cases in which this form of herbicide-free ridge tilIage was
applied to a corn-soybean rotation.
OCR for page 317
THE THOMPSON FARM
_
317
Pest Control
There have been no particular pest problems on the farm. In springs in
which cutworms are numerous, the Thompsons' fields do not seem to
suffer more or less damage than their neighbors' land. This observation is
perhaps surprising given the weedy appearance of the fields in spring;
cutworm moths often seek out such weeds. In terms of leafhoppers, which
can plague alfalfa, 1986 was a bad year. But there was no major damage
from the insects in particular, no yellowing of alfalfa on the farm. Possi-
bly, the diversity of plant species in the pastures and hay can be credited
for this effect: the seeding mixture contains alfalfa, red and alsike clovers,
timothy, and orchard grass. There is soybean cyst nematode in the county,
although it has not appeared on the farm; hairy vetch is said to be among
the many alternate hosts for this pest.
Labor and Costs
The Thompsons' diversified operation tends to spread the demands for
labor four full-time people over the whole year. The farming is done
mainly by Dick Thompson, his youngest son, Rex, and a hired man, em-
ployed full-time; occasionally, Sharon Thompson will also help, although
her primary responsibilities are as secretary, recor~keeper, receptionist, ac-
countant, and gardener. Rex Thompson is responsible for all machinery,
feed grinding and preparation, and the field operations; the livestock, and
especially the swine, are the responsibility of the other employee.
In 1984, when the demands of the farm's more than 200 field research
plots and the many speaking requests for Dick Thompson became too
numerous, the Regenerative Agriculture Association made it possible for
the Thompsons to hire a farmhand. The association also pays for soil and
leaf tissue testing; the farming operation itself, however, receives no outside
financial support. Dick Thompson estimates that 2.5 full-time persons are
employed in farming, and 1.5 persons do the research and demonstrations.
In terms of trips across the field, a conventional farmer might perform the
following operations to grow a crop of soybeans: one pass with a combina-
tion chisel plow-disk in the fall prior to the cropping year; a pass in the
spring to disk again and apply herbicide; two trips with a field cultivator to
incorporate the herbicide; a planting trip; one rotary hoeing after emer-
gence; two cultivations; and a final trip with an herbicide wick or spray
nozzle to get the remaining broadleaved weeds. The operations require nine
transits of the fielcI. The Thompsons, on the other hand, pull the manure
spreader over the field, plant, rotary hoe twice, cultivate three times, and
occasionally weed their soybeans with hand hoes, for a total of seven or
eight trips (Table 31. These weed control practices substitute labor for capital
and represent money kept within the operation as opposed to the purchase
of inputs. The expenses associated with the practices, such as the cost of
diesel fuel used in cultivation, are out-of-pocket costs. Rather than taking
OCR for page 318
318
ALTERNATIVE AGRICULTURE
TABLE 3 Thompsons' Time per Task Labor Costs for Corn and Soybeans
1986
Minutes per Acre
Field Operations Corn Soybeans
Spread manure and sludge 30 30
Mant 15 15
Rotary hoe (2 times) 15 15
Cultivate (3 times) 45 45
Harvest 30 30
Hoe weeds — 15
Shred stalks 15
Total time per acre 2:30 2:30
Cost per acre ($6.00/hour) $15.00 $15.00
out a loan in the spring to get the crops planted, the Thompsons are able to
distribute their expenses over the growing season and operate on cash flow
completely. Tables 4 and 5 compare the costs of production for the Thompson
operation with a conventional, cash grain, corn-soybean operation.
Soil Fertility
During the period when no fertilizers were purchased, soybeans were
nevertheless being sold off the farm; the onIv nutrient inputs were through
. .
TABLE 4 Cost Comparisons for Corn and Soybean Production Using
Thompson Methods and Conventional Methods
v
Corn (dollars) Soybeans (dollars)
Category Thompson Conventional Thompson Conventional
Cost per acre
Machinery 73.30 83.20 61.15 47.05
Seed 20.00 22.10 15.00 11.00
Chemicals 11.40 91.40 4.20 64.95
Labor ($6.00/hour) 15.00 19.20 15.00 16.80
Land 100.00 100.00 100.00 100.00
Total cost/acre 219.70 315.90 195.35 239.80
Cost per bushela
150 bushels of corn 1.46 2.11
50 bushels of soybeans 3.91 4.80
NOTE: A rigorous comparison of the Thompson Farm with Iowa State University (ISU) estimates
would require an economic analysis of entire rotations. Such analysis is beyond the scope of this
present study. The cost of vetch seed for the cover crop in corn and soybeans is omitted from the
Thompson data.
aThese estimates reflect average yields and expenses. ISU's estimated costs of production for
these crops are somewhat higher, indicating that the Thompsons' operation is profitable. Details
of the Thompsons' labor expenditures and production costs are presented in Tables 3 and 5.
SOURCE: Iowa State University. 1986. Estimated Costs of Crop Production in Iowa—1986. FM-1712.
OCR for page 319
THE THOMPSON FARM
TABLE 5 Variable Production Costs for Corn and Soybeans on Thompson
Farm, 1986 (in dollars)
319
Corn Soybeans
Operations and Materials (150 bushels/acre) (50 bushels/acre)
Ridge-tillage planting 9.70 9.70
Seed 20.00 15.00
Spread manure ($1.00/ton) 18.00 18.00
Purchased fertilizer
30 pounds N at $0.24/pound 7.20
30 pounds K2 at $0.14/pound 4.20 4.20
Herbicides 0 0
Rotary hoe (2 times at $1.75) 3.50 3.50
Cultivate (3 times at $2.95) 8.85 8.85
Corn picker 23.20
Combine — 17.75
Transport grain 10.05 3.35
Dry grain 0 0
Labor 15.00 15.00
Land charger 100.00 100.00
Total cost per acre 219.70 195.35
aThis cost is for comparative purposes. The Thompsons actually own the land.
purchased livestock feed. Dick Thompson has calculated that the theoretical
net gain-Ioss to the system per acre per 5-year rotation was: nitrogen, +101
pounds; phosphate, +112 pounds; and potash, - 336 pounds. In reality,
additional leaks in the system also occurred. Soil tests for phosphorus
showed a steady increase over this period, whereas potassium remained in
the medium range.
Leaf tissue analysis, although an additional cost, is a good way to deter-
mine the nutrient status of a farm's crop. Soil tests, on the other hand,
indicate only the probability of response to additional fertilizer. In humid
parts of the Midwest, testing for soil nitrogen is still controversial because
all of the variables involved are not yet fully understood. Tissue tests are
thus useful in taking some of the guesswork out of a fertility program.
When the Thompsons began tissue testing, they found that both nitrogen
anti potassium were below adequate levels. Their short-term solution was
to purchase moderate amounts of both, in the form of chemical fertilizers,
and to monitor nutrient levels through soil and leaf tissue tests. The tests
had shown that by June, the soil had as much as several hundred pounds
of nitrogen; at corn planting, however, around the first week of May, there
was very little available nitrogen. The Thompsons now apply 18 tons of
mixect sludge and manure per acre at planting of both corn and soybeans,
but the substantial amendments of green manure and livestock manure do
not begin to benefit the crop until the soil warms, allowing the microbial
breakdown of the added substrates. Currently, 30 pounds of nitrogen (N)
per acre, in the form of 28 percent N urea solution, is applied at the planting
of both oats and corn. In 1986, 30 pounds of potash per acre were also
applied to corn and soybeans at planting.
OCR for page 320
320
ALTERNATIVE AGRICULTURE
The farm's long-term strategy is to plug the nutrient leaks in the opera-
tion so that purchased inputs can be reduced or eliminated. For a number
of years the mixed livestock manure and bedding were composted before
they were applied to the land. Dick Thompson reported that this practice
has been discontinued for a number of reasons:
The success of the weed control program has made it less critical that
weed seeds be destroyed by comporting;
Nitrogen in the compost was apparently stabilized to such an extent
that it could not be mineralized fast enough to supply the corn crop;
In the composting process itself, nitrogen was volatilized and potassium
was lost in the liquid expressed from the compost windrow; and
Finally, the process required a year's delay between the collection of the
raw material and the application of compost to the field.
Dick Thompson also sees some evidence that compost is a less attractive
substrate for soil fauna and flora than the mix of bedding and raw manure:
the estimated earthworm population was significantly lower after the appli-
cation of compost than after raw manure or sludge.
The current plan for manure is to haul material from the livestock pens
directly to the new manure bunker where it is added to the sewage sludge.
In the bunker, the manure and municipal sludge will be kept coo! and
anaerobic. Any liquid that collects in the bunker will be pumped off and
used as a starter fertilizer in the spring.
The municipal sludge is delivered to the bunker at no cost to the Thomp-
sons. Sludge deliveries began in 1984 and now amount to about 1,200 wet
tons per year. Sludge is typically low in potassium, but the use of cement
kiln dust as a precipitating agent may increase the potassium content of the
material in the future. A tannery near Boone is responsible for the chro-
mium found in the sludge. Chromium levels are being monitored by the
city, however, and although there are no precise guidelines, it appears that
the metals now found in the sludge can be applied to the farm's land for
many years without causing problems.
The Use of Cover Crops
Cover crops are grown wherever possible on the Thompson Farm, both
for soil conservation and for soil improvement. The district conservationist
for the Soil Conservation Service has calculated annual erosion rates for the
farm's soils, estimating them to average 4 tons per acre per year for the
corn-soybeans-corn-oats-hay rotation and 1 ton per acre for the fields that
are in a corn-soybeans-oats-meadow-meadow-meadow rotation. (These es-
timates do not factor in the additional erosion control effect of the inter-
seeded and overseeded cover crops, which can be sizable when the cover
crops provide a high degree of ground cover.) The maximum tolerable
annual level of erosion in this area of Iowa is considered to be 5 tons per
acre. In Boone County, land in a corn-soybean rotation loses an average of
to 10 tons of soil per acre per year. All of the Thompsons' fields except
OCR for page 321
THE THOMPSON FARM
321
the cash grain experiments are in hay or small grains 2 years out of 5 or 3
years out of 6.
Winter ground cover is established after soybeans by aerially applying the
seed as the beans approach senescence. As the soybean plant leaves fall to
the ground, they cover the seeds, forming a good environment for germi-
nation. The cost of the service in this area is about $4.50 per acre, but it
costs considerably less in other parts of the country. Dick Thompson uses
the following application rates, which are fairly typical: 1 bushel of oats per
acre (currently priced at $2.50 per bushel for cleaned seed) with 20 pounds
of either hairy vetch (prices vary widely by locality, $0.38 to $0.70 per
pound) or rye (about $3.50 per bushel). Oats die in the winter In central
Iowa, an advantageous characteristic in that they provide ground cover
without interfering with the following year's crop. Rye is exceptionally
hardy and will grow vigorously the following spring. At seeding rates of
greater than 20 pounds per acre, however, rye can dry out the soil through
increased transpiration, hinder planting of the succeeding crop, and im-
mobilize soil nitrogen. The soybean harvest is too late in the year to allow
more than a few inches growth of a cover crop, but even such a late seeding
helps to hold the snow on the ground.
Cover crops are also seeded into corn at the time of its last cultivation.
Hairy vetch has been the best performer in this capacity, although its winter
hardiness is unpredictable. One stand of vetch on the Thompson Farm in
the spring of 1986 contained 40 pounds of nitrogen per acre at the end of
April and 75 pounds per acre by the end of May. These rates were deter-
· ~ ~ .
_` . ~ . . . ~
. .
, . , . ~ _ ,, _ _ ~ _ _
mined by excavating and analyzing the vetch in square-yard quadrants
every 20 rows along a transect across the field; plant samples were then
subjected to Kjeldahl analysis for nitrogen. Although the vetch roots were
profusely nodulated, there is no way of knowing how much of the nitrogen
was fixed from N2 and how much was simply accumulated from the soil.
The carbon:nitrogen ratio of this plant material was 10:1 or 12:1, so there
should have been no immobilization of additional soil nitrogen as the green
manure decomposed.
The cash grain rotations on the Thompson Farm do not receive applica-
t~ons ot manure or sludge. The green manure crop in the 3-year rotation is
grown only for nitrogen fixation and nutrient accumulation. In both this
and the corn-soybean rotation, seeds of rye, oats, or hairy vetch are aerially
seeded just before leaf fall of the soybeans. At the last cultivation, hairy
vetch is seeded into corn in both rotations for green manure the following
spring.
LIVESTOCK SYSTEMS
Feeds
A complete description of the feed rations used on the farm is available
from the Thompsons. The foundation beef cow herd ration is hay, oats, and
ground ear corn. Fattening cattle receive a protein supplement but no
OCR for page 322
322
ALTERNATIVE AGRICULTURE
growth hormones. There are five mixes for the hogs: one for gestation, one
for lactation, a pig starter, a nursery grower, and a finishing ration. The
sows get ground ear corn, oats, and purchased Tysine and minerals. The
other pigs are given ground, shelled corn (some of which comes from on
the farm, some from outside), ground oats, and mineral and protein sup-
plements.
The cattle previously raised by the Thompsons were a large, exotic type
that in winter required a great deal of corn just to maintain weight. The
smaller, hardier Black Baldies that the Thompsons currently raise do well
on mostly had. (The Thompsons have changed from spring to fall calving,
. . . . ~ . . . ~ , . · · .. . . ~ . . .
which has solved the problem ot calving In tne yarn oetore cows get out to
pasture in the spring and so helped to eliminate scouring in the calves.)
Similarly, the hogs used to be of a tall, narrow body type, but eventually
the Thompsons concluded that a medium-framed animal with more Jung
capacity was better suited to the outdoor environment that the farm main-
tains.
Disease Control
The Thompsons do not use antibiotics routinely in their livestock opera-
tions, and the cattle receive no vaccinations. Diatomaceous earth is added
to the feed and is dusted on the cows once or twice a year for external and
intestinal parasites.
The isolation, sunlight, and generous amounts of bedding the Thomp-
sons use in the hog operation help to lessen the pressure from disease
organisms. Agricultural calcium carbonate (fine barn lime) is spread on the
floors to keep the pH above the range favored by potential pathogens. The
pens are cleaned every 2 weeks with the front-end loader tractor, but the
facilities have never been sterilized. Manure is moved weekly from the
farrowing units to the gestation pen so the sows are exposed to the same
microflora found in farrowing stalls. In this way, pregnant sows build im-
munity to any new microbe in the environment, and the piglets begin life
with the corresponding passive immunities.
Antibiotics create a "vacuum" in the gut of an animal, a vacuum into
which resistant pathogens may move with relatively few constraints. No
amount of sterilization can keep a sow's microflora away from her piglets.
Rather than add antibiotics to the hog rations, the Thompsons add one or
more of a group of products referred to as probiotics. These additives
contain live cultures of bacterial strains, prominently Lactobacillus species
but also strains of Streptococcus, Bacillus, and probably other genera.
The goal of their use is to create a favorable and stable balance in the
hog's gut through this selective diversity. Some of these probiotics seem to
be effective in preventing scours, which is also avoided through the inclu-
sion of oats and ground ear corn for bulk in the sows' gestation ration. As
a further preventive measure, piglets get steamed rolled oats in a ration
that contains no added sugars and only 16.5 percent crude protein.
AD of the hogs are chased out of their hutches early every morning to
OCR for page 323
THE THOMPSON FARM
323
discourage them from dunging inside. If the number of pigs in a unit is
sufficiently high, they tend to defecate outside rather than foul the building
in which they sleep. As the pigs grow, walls are removed to increase the
size of their sleeping space or the number of pigs per unit is reduced or
both. Iron shots are the only injection the Thompsons customarily admin-
ister in the hog operation.
TRANSFER OF TECHNOLOGY
Communication between the academic community and limited-input
farmers like the Thompsons has improved over the years. There are proba-
bly at least several reasons for this improvement:
Limited input farmers rely on sound management and agronomic orin-
ciples rather than adhering to specific ideologies;
The practices used on these farms are supported by empirical data, and
incorporate many proven agricultural methods such as crop rotations;
Individual scientists and farmers have worked to develop the dialogue;
and
Circumstances in the farm economy and the environment have led farm-
ers to consider the philosophy of optimization rather than maximization
in ways that might not have been foreseen a decade ago.
.
O
.
Every summer, several hundred people are drawn to the Thompson Farm
field days. A number of researchers, teachers, extension agents, and admin-
istrators have visited the farm at one time or another and been struck with
its accomplishments and successes. So far, most state universities have not
moved to develop and promote input-efficient farming ner se an has horn
done, for example, with no-tillage cropping. For such research to occur on
a more systematic basis, the Thompsons believe that funding must be
available.
During discussions at the Thompson Farm field days, questions were
raised about three major problems confronting agriculture: (1) the farm
credit crisis, (2) the oversupply of grain, and (3) the environmental effects
of production. In addressing these problems, the Thompsons stress the
links among farm management decisions (such as what to plant or which
tillage systems or disease control practices to use), economic performance,
and reduced environmental degradation. The Thompson Farm represents
one possible integrated solution to all three problems.
Experience from around the country has shown that for the methods
used in the Thompson operation to be more widely adopted, farmers must
first see them working in their own neighborhoods. They tend to view
advice from leaders in government, universities, and the private sector more
skeptically. As a result, demonstration farms, such as the Thompson Farm,
play an important role in technology transfer. The Thompsons believe that
the growing crowds at their field days and the desire of research scientists
to conduct more in-depth studies of the family's farming system are positive
signs.
1 ~ --I I-- ~~~ A ~~
Representative terms from entire chapter:
weed control
