Organic Crop Production: Well‐thought‐out crop rotation is worth 75% of everything else that Crop Rotation might be done, including fertilization, tillage and pest control. ‐Firmin Bear Annette Wszelaki Vegetable Specialist Why rotate? What is crop rotation? Maintains good soil health and quality Fosters the most effective use of soil fertility Crop rotation is selecting a sequence Helps control weeds, some diseases and insects of crops for a field that improves soil Reduces need for off‐farm inputs quality while it sustains the farmer. Enhances moisture management Promotes income diversity and stability Improves crop quality and yields Reduces soil erosion Increases biodiversity Improves water quality Reduces drought impact Decisions, decisions… Why bother?With a 3 crop, 4 A good rotational sequence can accentuate year rotation, there every possible advantageare 6 possible sequences Different crops use soil nutrients differentlyWith a 3 crop, 8 All may alter or be altered by the succeeding or year rotation, there preceding cropare 5,040 Time spent planning a rotation is never wasted!sequences! THINK IT THROUGH!
Rotation Lengths to Reduce Soilborne PathogensInsect, Disease and Weed Control Vegetable Disease Yrs w/o Susceptible Crop Asparagus Fusarium rot 8Monoculture encourages pest problems Cabbage Clubroot 7A good rotation can prevent the build‐up of Cabbage Blackleg 3‐4 Cabbage Black rot 2‐3specific pests and weeds Muskmelon Fusarium wilt 5 Parsnip Root canker 2 Peas Root rots 3‐4 Peas Fusarium wilt 5 Pumpkin Black rot 2 Radish Clubroot 7 Source: S.A. Johnson & P.J. Nitzche, USDA Plant Nutrition Soil StructureRotations can make nutrients more available Rotations preserve and improve soil structurePlants of a lower order of evolution better Maximize benefits of crops with different feeders on less soluble sources of nutrients rooting depths i.e., alfalfa, clovers and cabbage versus lettuce and cucumbers Yields Things to consider:Some crops helped, others hindered by preceding crop How they help: How they hinder: Number of blocks or sections Increase soil N Deplete soil nutrients Rotation works best if sections are all the same size Improve soil condition Excrete toxic substances Number of years in rotation cycle Increase microbial activity Increase soil acidity 10 sections does not necessarily = 10 year rotation Excrete beneficial Make soil condition Do what makes sense for your operation! substances unfavorable Number of crops in rotation Control pests Lack of proper aeration Most small growers have many diversified crops Remove moisture Crops must be further divided based on botanical Vector disease classification, plant part consumed or space utilized
Crop Families Crop Families Brassicaceae (Cabbage Family) Fabaceae (Bean Family) Cabbages, cauliflowers, kale, broccoli, turnips, Snapbeans, lima beans, broad beans, half‐ radishes, mustard, Brussels sprouts runners, field peas, English peas Can have allelopathic effect on subsequent crops Fix nitrogen from the air for their own fertilizer Solanaceae (Tomato Family) and for subsequent crop Tomatoes, potatoes, peppers, eggplant (okra) Alliaceae (Onion Family) Need fairly high level of nitrogen Onions, leeks, shallots, garlic Potato prefers soil slightly more acidic Monocot Crop Families Crop Families Cucurbitaceae (Squash Family) Chenipodiaceae (Chard Family) Squash, cucumber, melons, pumpkins, gourds Beet, spinach, Swiss chard, lambsquarters Long growing season Mycorrhizae will not associate Apiaceae (Carrot Family) Asteraceae (Lettuce Family) Carrots, parsnips, parsley, celery, celeriac, dill Lettuce, salsify, Jerusalem artichoke Dill enhances cabbage family, onion and lettuce Poaceae (Grass Family) Corn Crop Space Requirements Nutrient Feeding Some crops are heavy feeders that deplete soils, More Space Less Space 6 5 4 3 2 1 while other crops are light feeders that build soils. Corn Potato Tomato Lettuce Onion Pea Cauliflower Pepper Beet Soil Depleting Crops Winter Broccoli Carrot Chard Row crops‐ corn, soybeans, vegetables, potatoes squash Summer Parsley squash Celery Soil Neutral or Soil Conserving Crops Bean Parsnip Cabbage Rutabaga Cereal crops‐ wheat, barley, oats Spinach Kale Radish Soil Building Crops Brussels Legume sods‐ alfalfa, clover sprouts Cucumber Grass sods‐ prairie grass, meadows, pastures
Year 1 Year 2Year 3 Coleman’s 8‐year Vegetable Crop Rotation Cover Crop/Green Manures UsedColeman’s 8‐year Vegetable Crop Rotation Coleman’s 8‐year Vegetable Crop Rotation Potatoes follow sweet corn because research has Sweet corn follows the cabbage family because, in shown corn to be one of the preceding crops that contrast to other crops, corn shows no yield decline most benefit the yield of potatoes. when following brassicas. Also, the cabbage family can be undersown to a leguminous green manure, which, when turned under the following spring, provides the most ideal growing conditions for sweet corn.
Coleman’s 8‐year Vegetable Crop Rotation Coleman’s 8‐year Vegetable Crop Rotation Peas follow tomatoes because they need an early seedbed, and tomatoes can be undersown to a non‐ The cabbage family follows peas because the pea winter‐hardy green manure crop that provides soil crop is finished and the ground is cleared (early) protection over winter with no decomposition and allowing a vigorous green manure crop to be regrowth problems in the spring. established.Coleman’s 8‐year Vegetable Crop Rotation Coleman’s 8‐year Vegetable Crop Rotation Beans follow root crops because they are not known to be subject to the detrimental effect of certain root Tomatoes follow beans because this places them 4 crops, such as carrots and beets, may exert in the years away from their close cousin, the potato. following year.Coleman’s 8‐year Vegetable Crop Rotation Ogden’s 4‐year Rotation Cycle leaf crops fruit cropsSquash is grown after potatoes in order to have two “cleaning” crops back to back prior to the root crops, thus reducing weed problems in the root crops. legumes root crops
Don’t forget cover crops or green Companion Planting manures in your rotation!Investment in weed and pest control Mix it up!Vegetable systems have many windows to include cover crops or green manures All of one crop or crop family does not have to Example: Between harvest of early planted spring go in the same block! crop and planting of fall crops Three Sisters Buckwheat, cowpeas, sorghum‐sudan Herb‐Vegetable Combinations Plant winter annual on fields that would lie fallow Many veg crops can be overseeded with cover Select crops that can tolerate shade and traffic UT Organic Crops Field Tour Future Workshops Planting: Seed Sources & Transplants (May 11) Identifying and Managing Weeds (June 8) Identifying and Managing Pests (July 13) High Tunnel Production (August 10) Identifying and Managing Diseases (September 14) •May 15, 8 AM – 11:15 AM Developing an Organic System Plan (October 12) •Pre‐register with ETREC by calling 865.974.7201 •Visit http://organics.tennessee.edu for more info Marketing Organic (November 9) Questions? Annette Wszelaki email@example.com (865) 974‐8332 http://organics.tennessee.edu Organic Crops Field Tour: May 15