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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
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.
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.
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
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
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 SummaryIowa, 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
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 . . .. . .
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
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.
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
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 Iowa1986. FM-1712.
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.
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
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
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
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 ~~