This section discusses each of the key responsibilities in the “Managing a Crop Rotation System” chart and illustrates some of the important, difficult, or less obvious tasks, with examples from the operations of expert farmers (see sidebar 2.7).
Responsibility A: Identify Rotation Goals
Rotations are a means to meet overall farm goals. Expert farmers manage their field rotations in the context of their whole farm systems. Although they may not consciously review them, each farmer has a set of farming goals that guide rotation planning for each field and for the whole farm. Some goals are common to all farms (sidebar 2.8); others are unique to a particular farmer. Examples of experts’ rotation goals include:
- Jack Gurley’s goal is to maximize production on 100 percent of his small acreage without sacrificing soil health and tilth.
- One of Will Stevens’s goals is to design rotations to keep brassicas out of fields with a history of clubroot.
- Since Jim Gerritsen produces certified seed potatoes that must be disease free, the goal of his entire rotation is to control potato diseases and increase organic matter.
Under responsibility A, the most important and most difficult task is reviewing the overall farm operation. This includes reviewing the production plan: the crops, cover crops, fallows, and livestock that need to be allocated to particular field areas in the coming year. Certain factors— including cropland available, equipment, cash flow, crop mix, and marketing strategies—define the parameters within which the rotation must be designed. Another important task is to identify which problems can be addressed by rotation.
Most Important and Most Difficult Tasks
Expert farmers built the chart “Managing a Crop Rotation System” by reaching consensus on the key responsibilities and tasks involved in managing a crop rotation system. Other expert farmers reviewed the chart and indicated the ten most important tasks and the ten tasks they considered most difficult to perform. Tasks are listed in order of most to least. Codes in parentheses correspond to the number of the task on the chart.
Ten Most Important Tasks
- Maintain crops. (F-12)
- Implement production plan. (F-4)
- Prepare soils as soon as weather permits. (F-9)
- Plant crops. (F-10)
- Walk fields regularly to observe crops and fields. (C-1)
- Review overall farm operation. (A-2)
- Draft annual [rotation] plans. (E-15)
- Monitor soil and crop conditions. (F-6)
- Adjust actions according to field and crop conditions. (F-13)
- Identify problems that can be addressed through rotation. (A-3)
Ten Most Difficult Tasks
- Assess profitability on a whole-farm and crop-by- crop basis. (G-5)
- Maintain crops. (F-12)
- Assess whether pest, disease, and weed pressures must be addressed. (D-4)
- Investigate new market opportunities. (H-3)
- Review overall farm operation. (A-2)
- Review regulations. (B-13)
- Analyze weather probabilities. (D-1)
- Determine if successes or failures were due to on-farm or regional factors. (G-11)
- Develop collaborations to verify successes and solve problems. (H-2)
- Tweak the crop mix. (H-4)
Responsibility B: Identify Resources and Constraints
Identifying the possibilities and limits of the overall farm production plan and the rotation for each field is central to planning. At the farm scale, parameters such as market demand, available land, equipment, projected labor availability, and regulatory issues have to be reviewed annually. Farmers consider complying and keeping up with regulations to be among their most difficult tasks. This responsibility also includes numerous “communication” tasks, such as establishing market relationships, making labor arrangements, accessing information, and contacting suppliers.
Constraints may include field-specific limits like whether a field is ready for planting and harvest early or late in the season and how that relates to market timing, cash flow, and profitability. Problems of specific fields in a particular year must be identified. For example, heavy weed pressure the previous season may preclude small-seeded crops. Crop cultural needs, such as spacing and trellising, also have to be accommodated. Constraints imposed by equipment, such as row width, must be figured into the rotation plan. Crops with similar irrigation, fertility, labor, and cultivation regimes or planting times are often managed as a block to simplify field operations.
Expert Farmers’ Common Goals for Crop Rotation
- Maintain healthy soil (including chemical balance, drainage, humus, vitality, biological health, fertility, nutrient cycling, tilth, organic matter, and soil cover to prevent erosion); for example: “Conserve and build organic matter in my light sandy soil.”
- Produce nutritious food.
- Control diseases, especially soilborne diseases; for example, “Break the wilt cycle among crops in the tomato family.”
- Reduce weed pressure; for example, “Manage the rotation to confuse the weeds.”
- Increase profitability.
- Have a holistic approach and a good rotation that leads to healthy crops.
- Manage the farm as a whole system.
- Have a diverse line of products to market.
- Provide economic stability.
- Control insects.
- Add nitrogen and other nutrients in a way that is environmentally safe and conforms with regulations.
- Maintain biotic diversity.
- Unlock the living potential of the soil.
- Reduce labor costs.
- Balance economic viability and soil fertility.
- Diversify tasks to keep labor happy and productive all season.
- Balance the needs of the farm with the needs of the farmer.
- Minimize off-farm inputs.
- Capture solar energy wherever possible.
- Refine the aesthetic quality of fields and farm.
- Bring the farmer to life; develop a spiritual relationship with the land.
Responsibility C: Gather Data
Rotation decisions, for each field and for the whole farm, are based on an impressive array of information. Some information is collected on the farm, and some is gathered from off-farm sources. Observing crops and fields is on the expert farmers’ list of the ten most important tasks (sidebar 2.7). All the expert farmers agreed that regularly walking the fields is a crucial way to gather data and monitor ongoing conditions for the current and coming seasons. Will Stevens interviews his workers throughout the season, because they are able to observe many field situations he does not have the opportunity to see. Even in winter, expert farmers are observing their fields, sometimes while cross-country skiing or walking the dog. This helps them review field conditions and logistics of previous seasons and organize their thinking for the season ahead.
Production and marketing information usually needs to be updated and cross-checked annually. A new crop, research recommendations, or market arrangements may require that new data be considered. For example, seed potato grower Jim Gerritsen uses his rotation to interrupt potato disease life cycles and pest vectors. He reviews the scientific research annually, staying current to take advantage of any advances in the understanding of the ecology of his system.
Tasks C-9 and C-10, “Categorize crops” and “Categorize fields,” are among the most critical steps in data gathering. Categorization of crops and fields helps guide the optimal allocation of particular crops to individual fields or beds each year. These tasks rely on the cumulative process of integrating information and experience over many growing seasons. Information about both crops and fields is necessary to effectively match them in a given year. The first task is to characterize every cash and cover crop in the farm’s crop mix according to a range of important characteristics, from the number and timing of harvests to soil requirements (see sidebar 2.9). Farmers also characterize their fields, on the basis of the field’s permanent characteristics (such as slope and exposure) and shorter-term conditions (such as weed pressure). Categorizations provide a reference of “interchangeable crops” if a plan needs modification. For example, it is useful to know what late crops or varieties can go into a field in a wet year. The variety of characteristics considered indicates the complexity of the issues farmers balance in crop rotation decisions.
Categorization of Crops and Fields
|Crop Characteristics||Field Characteristics|
|The list below lists crop characteristics from most to least important, as ranked by expert farmers.||These relatively permanent characteristics of a field are difficult to change; many affect the type of equipment that can be used and the timing of operations.|
Season of planting, harvest, labor, and land use
Susceptibility to pests and diseases
Cash vs. cover crop
Ability to compete with weeds
Annual, biennial, perennial, or overwintering annual
Direct-seeded vs. transplanted
“Givers” vs. “takers”
Heavy vs. light feeders
Cultural practices (for example, spraying, cultivation, irrigation)
Preferred seedbed conditions
Income per acre
Effect on cash flow
Costs per acre
Tolerance of mechanical cultivation
Ability to trap nutrients
Root vs. leaf and fruit
Row vs. block planted
Large vs. small seeded
Deep vs. shallow rooted
Tolerance of poor drainage
Shade tolerant vs. intolerant
|Recent planting history (1–5 years)|
Proximity to water source
Sunny or shady
Known problems with weeds
poor tilth or hardpan
Natural Resources Conservation Service (NRCS) soil type
Aspect (north, south, east, west)
Air drainage—frost pockets
Proximity to barn or access roads
Shape (corners, row lengths)
Proximity to similar fields
Responsibility D: Analyze Data
All of the decisions and information generated through previous tasks and responsibilities are pulled together for analysis at this key phase of the planning process. The data on market options, equipment, labor and seed availability, and financial constraints, along with the overall farm and rotation goals are reviewed. Information is cross-referenced and, when necessary, weighted. Possible trade-offs are considered. For example, the field crew may be able to plant two fields to high-value crops but not also harvest an early crop the same week. Crop cultural needs are compared to each field’s characteristics and conditions. The experts assess soil conditions and determine how pest (animal, insect, weed) and disease pressures from the previous season should be addressed. This is among the most difficult tasks. Even weather projections are considered. Every possible crop mix is analyzed. Various possible pairings of crop to field are outlined, and options for each field are compared.
Responsibility E: Plan Crop Rotation
This responsibility is the ultimate synthesis of information and results in a production plan and a rotation plan. Expert farmers distinguish between these two types of plans. The production plan specifies what needs to be grown (the crop mix) and how it will be grown, whereas the rotation plan determines where each crop will be planted. Final decisions about the crop mix and the allocation of crops to fields and fields to crops are pivotal to this responsibility. Information such as what crops to grow, in what quantities, labor availability at various times in the season, required equipment, and desired harvest dates are integrated into the rotation plan for each field and for the entire farm.
Two questions bounce back and forth. One is what will be grown in each field? The other is where will each crop grow? These questions are answered based on observation and experience. Several steps are involved. First, the cropping history of each field or bed for the past three or more years is reviewed. This includes what crops and crop families were grown; how well they performed; any particular successes or failures; and any logistical issues relating to equipment use, irrigation, harvesting, or labor. Obviously, the size of the field and market needs (how much of each crop is required) are also considered. The allocation of crops to fields includes consideration of future cropping plans as well as the cropping history of a field. The rotation plan must be responsive to weed pressures or other legacies from earlier years and must provide future crops with favorable conditions.
Expert farmers first assign their highest-priority crops to fields (or beds). High-priority crops include the most profitable crops, cover crops with the greatest benefits, and crops particularly vulnerable to pests, diseases, or weather. Decisions are also based on high-priority fields—for example, those that have the highest fertility, are prime locations for u-pick crops, or have current problems that need to be addressed. Remaining fields (or parts of fields) are then assigned to the remaining crops, cover crops, fal- low areas, and sometimes pasturage for livestock. All these decisions are based on both business and biology. An example is provided in sidebar 2.10.
The crops and fields are tentatively matched, creating a cropping plan for the entire farm for the year. Many experts plot this information on farm maps and notebooks. They take this initial plan and, in the words of one, “Farm it in my head.” That is, they work through the sequence of field operations from tillage to harvest over the entire season for each crop and field. Several expert farmers take their plans into the field and walk the farm for this task. They think through why any sequence might not work, reviewing any possible logistical or biological conflicts like timing of operations or spread of pests between adjacent crops. They then adjust the plan as necessary.
Grouping Crops by Their Need for Accessibility
The logistics of harvesting affect rotations. For example, crops with frequent harvests or need for frequent care must be easily accessible. Expert farmer Jean-Paul Courtens considers road access and produce characteristics. He prefers to allocate some crops to fields with close proximity to packing sheds. Long rides on bumpy roads can bruise delicate produce like tomatoes. He locates salad greens and braising greens in the same field due to the time of day they are harvested. Crops are also grouped based on the time of the season when they are harvested.
Responsibility F: Execute Rotation
Farmers indicated that executing the rotation involves many of the most important and difficult tasks (see sidebar 2.7). They identified maintaining crops (including activities such as weeding, thinning, and irrigation) as the most important task and the second most difficult task in crop rotation. Scheduling tillage and planting for all the fields across an entire farm every season is also a challenge for most farmers. Although they generally want to till the soil as early as possible to accelerate soil warming and residue breakdown, they must wait for workable soil moisture conditions. Other critical steps in crop production and central to executing the crop rotation are soil preparation and planting. Delays in soil preparation or planting may cause crop failures due to poor emergence, runaway weeds, or inadequately broken down cover crops and require shifts in the crop rotation (see sidebar 2.11).
Expert farmers attempt to plant priority fields or beds and their most important crops as scheduled in their plan. If they have to alter the plan, they still prioritize high-value or sensitive crops and fields. Many decisions and adjustments have to be made on the fly.
In early spring, farmers monitor the weather—sometimes hourly—as they implement and alter their rotation plan. Problems related to weather, cover crop maturity, crop emergence, and weeds may cause farmers to alter their original plan. Soil moisture conditions affect the timing of tillage and subsequent field operations (see sidebar 2.12). Cover crops are monitored to determine maturity, thickness of stands, and optimal time for incorporation. Farmers also monitor the breakdown and incorporation of crop and cover crop residues. Soil and air temperatures influence planting and transplanting decisions, as well. Any of these factors can cause crops to be reassigned to different fields or beds.
While a change necessitated by weather or the conditions in one field can cause reassignment of crops around the farm, general and farm-specific rotation goals and guidelines remain the basis of every decision; for example, cucurbit crops will never be planted in the same field two years in a row. Most expert farmers anticipate problems that might occur and have contingency plans ready (see sidebar 2.13). Expert farmer Paul Arnold suggested that this ability to make effective on-the-fly adjustments is an important factor in the success of his farm. In the event of crop failure, crops may be abandoned, replanted, or replaced with a cover crop or even a different cash crop. Drew Norman, another expert farmer, described this pro- cess as finding “a profitable punt.”
As the season progresses, short-season crops like salad greens are harvested, subsequent crops are planted, and cover crops are seeded or plowed under. Even as the rotation plan is implemented, the process of crop-to-field allocation and prioritization continues. The expert farmers emphasize the importance of recording actual cropping as it happens (particularly deviations from the plan) for later comparison with their initial rotation plan for the year.
After harvesting late snap beans, wet weather prevented expert farmer Roy Brubaker from fall-seeding a rye cover crop in a particular field. One option for the field might have been to plant oats and field peas in early spring, which would have had to be plowed down prior to planting fall brassicas. Another option would have been to plant the field to a spring crop of brassicas and then put in buckwheat or an early rye cover crop. Either decision had repercussions for the rotations on other fields because the farm’s CSA needed both spring and fall brassicas.
Nonuniform cover crop growth does not change Brett Grohsgal’s overall rotation, but it can change his crop mix or the selected varieties on a particular field. He may subdivide the field and plant heavy feeders where the legume cover crop was most successful. For example, beefsteak tomatoes, which are heavy feeders, would get that part of the tomato acreage that had good cover crop growth; whereas thrifty cherry tomatoes would get the remainder. Alternatively, he might plant heavy-feeding and high-value watermelons on the most fertile, weed-free areas, whereas lower-value and resilient winter squash would be assigned to the less fertile areas.
At both farms, all the options are considered before finalizing a decision.
Field and Crop Conditions That Expert Farmers Monitor
Fields and crops need continual monitoring during the season. Biological and physical conditions can change relatively quickly due to management, weather, and mistakes. Experts often have contingency plans in mind to accommodate such situations, especially for their priority fields and key crops. In-season observations also inform experts’ decisions for the next year’s rotation. Although most farmers do not measure all these parameters directly, they are aware of, observe, and monitor conditions in their own ways. Conditions they monitor regularly include:
- Weed pressure
- Insect emergence and pressure
Cover crop performance
- Success of previous cover crops (e.g., production of organic matter, weed suppression)
- Ground cover
- Cover crop nodulation and nitrogen fixation
- Soil test results
- Chemical balance (N, P, K, Ca, Mg, and micronutrients)
- Nutrient cycles
- “Biological health and vitality—earthworms, etc.
- Soil organic matter
- Crop residues and residue breakdown
- Composted organic matter or “humus” in the soil
- Soil aggregation
- Soil moisture
- Soil and air temperature
- Soil compaction and porosity
Responsibility G: Evaluate Rotation Execution
Throughout the season, expert growers monitor the performance of their fields, each crop, and the farm as a whole. They record how their plans have worked and evolved. This is not just to solve problems in the current season, but also to observe, learn, and collect ideas and data for future seasons. Expert farmers do this directly and through communicating with their crews. Several said they interview their field crews at the end of the season. Workers often have suggestions, such as improving the farm layout, that enhance the efficiency of operations.
At the end of the season, growers carefully assess what actually happened relative to what they expected based on the original rotation plan. The factors they consider include yields; soil conditions; timing of events and operations; costs of crop production; disease, weed, and pest levels and their control; crop losses; labor satisfaction and efficiency; and profitability of each crop and of the whole farm. By walking around the farm and by analyzing data at their desk, they review the success of the production year. They compare the results with those of previous years to detect any trends or patterns. When attempting to analyze the causes of success or failure of various elements of the rotation, growers talk to other growers and extension agents to determine whether problems were the result of actions on their farm rather than, for example, a bad disease year for all farms in the region, regardless of rotation. Assessing whether regional conditions or on-farm mistakes were the source of problems is among the most difficult tasks, even for experts.
Rotation goals and rotation plans serve as benchmarks to measure the success of the cropping season and the rotation. Expert farmers consider how closely they followed biological principles in their rotation, whether they met their production and market objectives, and how their rotation execution supported their biological and business goals. Successes and failures are assessed, analyzed, and evaluated. The results are recorded to assist in planning and management for future seasons. Farmers note that assessing the profitability of crops, especially on a field-by-field basis, is another difficult task.
Expert farmers have enough experience to know that their best plans can sometimes be derailed. Knowing how to adapt or when to start over with a particular field or crop is essential to the success of the farm business. Expert farmers have developed many techniques to help them adapt to changing circumstances that typically influence their rotations.
Delayed planting due to wet fields
A common reason to diverge from the rotation plan is wet fields in spring. This can delay the plow-down of cover crops and, consequently, of residue decomposition, field preparation, and transplanting. Many expert farmers switch key crops to other fields when this happens, causing a cascading (somewhat pre-planned) shift in the allocation of many crops.
The growth of transplants in greenhouses is monitored to determine whether transplants are on schedule for planting out, relative to soil and weather conditions. Greenhouse environments are managed to speed or slow growth so that transplants are at the right developmental stage when field conditions are right for transplanting. Transplants will also be “hardened off ” to prepare them for the shock of the particular season’s outside environment.
David Blyn replants crop failures with fast-growing, short-season crops like radishes. He stocks extra seed for crops like sweet corn and carrots that can be planted on multiple occasions and replants when necessary. He often finds that the reason for failed germination was a poor seedbed, and on the second try the seedbed is usually better.
Blyn also uses cover crops to “paint in” gaps caused by failed crops or early harvests.
Brett Grohsgal responds to heavy weed pressure by sowing cover crops at higher rates.
Crops with bad weed problems are often plowed down and planted to cover crops. Eero Ruuttila uses a cover crop of oats and field peas for this purpose, which also produces a marketable crop of pea shoots.
Growers sometimes have to decide whether a cover crop stand that has a lot of weeds is worth keeping for the fertility benefits or should be plowed under early. They weigh the potential benefits and investment in the cover crop against potential increases in the weed seed bank.
One expert farmer uses intensively cultivated crops to control bad weed infestations. For example, infestations of bindweed and Canada thistle are followed by a triple crop of lettuce, which is high value enough to justify the costs of frequent cultivation. This is followed by a weed-suppressing cover crop of rye.
Drought can affect the germination of direct-seeded crops and shallow-rooted crops like garlic. Contingency strategies include mulching instead of cultivation for weed control, and substituting larger-seeded or transplanted crops.
In the event of drought and limited water for irrigation, Don Kretschmann irrigates only the portion of the crop destined for retail markets, allowing the wholesale portion of his crops to perish.
When an oat and pea cover crop does not winterkill, it delays planting of strawberries because of the time needed for the cover crop to break down. In that situation, Roy Brubaker plants the strawberries close together so their runners will fill in the rows more quickly for good weed control.
Severe pest and fertility problems
Brett Grohsgal occasionally finds that a whole field needs to be temporarily removed from production to rebuild fertility or manage weed infestations. He chooses sequences of cover crops based on ability to add organic matter, fix nitrogen, survive drought, and compete with weeds. He often pastures livestock on these fields to disrupt weeds and add fertility.
Responsibility H: Adjust Rotation Plan
As the cropping season closes in late fall, expert farmers begin the final phase of the annual rotation cycle in which they modify their rotations and plan for the coming year. This occurs concurrently with the evaluation of the past season. They revisit the tasks associated with “Identify rotation goals” (Responsibility A). They then focus on the productivity and problems of each field and of the overall farm. They first consider altering the crop mix by adding or removing crops or changing the area planted to a crop. Such decisions are affected by the market, as well as by field and crop performance and rotation imperatives. For example, Paul and Sandy Arnold found that high-quality, disease-free beets were very important for sales at farmers’ markets, so they decided to open up new acreage to break up the life cycle of soilborne beet diseases. This resulted in adjustment of their entire rotation so that their fields spend a longer time in cover crops.
Growers may also decide to change their field management by changing the order or dates of planting or plow-down of cover crops. They may decide to shift crops to alternative fields, try new crop sequences, or improve fertility of a field by planting it into a cover crop or hay ahead of schedule. They record notes for the next year’s rotation plan, new guidelines for contingencies, and results of experiments. The next year’s plan begins to take shape.
Adjusting the rotation plan presents three particularly challenging tasks: (1) developing collaborations to solve problems, (2) investigating markets, and (3) tweaking the crop mix. Tweaking the crop mix requires balancing market opportunities with biological needs. Growers indicated that this is a core task in managing crop rotations.
Expert growers stress the importance of experimentation, play, and a sense of adventure in managing their rotations. The art of adjusting every aspect of the rotation was discussed as the core of successfully managing rotations. While the NEON chart makes rotation planning seem linear and quantifiable, all of our farmer panelists felt that managing rotations is a continuous, integrated, intuitive, and cyclical process developed through intensive information gathering and extensive experience. They glean and incorporate new ideas into their rotations, which continue to evolve. These expert growers agreed on the importance of making new and interesting mistakes each season.