Monday, April 15, 2013



Pre-emergent cultivation/ blind cultivation.

The point of blind cultivation is to stir the top half inch of soil, adding air and causing the millions of tiny germinating weed seeds to dry out and die. The larger crop seeds are below the level of the cultivation and remain undamaged. Weed seedlings are at their most vulnerable at this stage. Effective blind cultivation will give you the biggest possible crop/weed size differential.” Rodale Institute

Other methods, such as timing can reduce weeds such as “Ohio organic grain farmer Dean McIlvaine waits until May or even early June to put in his corn crop. At this time the soils are warmer and plants grow more quickly, out-competing weeds. A delayed planting also gives McIlvaine time to make an extra trip with a disk or field cultivator to kill more germinating weeds.”

 Vegetative and synthetic mulches

Mulches can be very effective at controlling weeds. Mulch changes the environment around the soil surface, making it difficult for weed seeds to germinate and grow. Vegetative mulches, such as rye straw, can also suppress weeds by allelopathy. Research shows that rye mulch can reduce weed seed germination by 75 to 95% while leaving large-seeded crops such as corn, peas, cucumbers or beans unaffected.   

Natural or non-synthetic mulches such as straw or leaves can have the additional benefit of boosting soil organic matter over time, and even adding fertility. Be careful whenever you import mulch (or compost) materials such as leaves, loose straw or grass clippings that you avoid potential contaminants or debris. Avoid glossy inks from newspaper inserts and magazine waste.

"Living mulches" are cover crops of clover, grasses or other species used to suppress weeds in orchards and some other types of cropping systems. These can be mowed regularly or seasonally to maintain the stand.”  Taken from Rodale Institute Organic Transition

“Livestock: Intensive rotational grazing is widely recognized for its effectiveness in limiting perennial weeds in pasture. But in some specialized systems, farmers have developed additional ways to use livestock for weed management. Chickens confined to small pens and rotated through fields have been shown to be effective at eradicating yellow nutsedge. Geese preferentially eat grasses, and so can be used to weed strawberry fields without damaging the crop. Some tree-crop farmers use sheep to graze the alleys between rows of trees or coffee bushes.” Organic transition, Rodale Institute

Research at the Rodale Institute, moreover, “has shown that organic crops actually have a greater ability to tolerate weeds than non-organically managed crops do. In almost 30 years of side-by-side trials, our organic plots have consistently yielded as well as our non-organic plots, even though the organic plots usually have heavier weed pressure. It may be that the organic crops suffer less competition from weeds because soil quality is better, making nutrient and water resources more plentiful.”

NonGMO base synthetic material is acceptable in Organic production but Organic farmers must prove that the two methods of
  1. Cultural(crop rotation, sanitation, seed variety) Mechanical or physical (exclusion, beneficial insect habitat, lurs, traps, repellants, mulches, flame)
  2. Natural biological, botanical or mineral inputs
did not work and it must be documented to prove they were ineffective.

It all goes back to soil health and conservation planning.  Know your weeds and which crops, cover crops and rotation cycles are needed to control the problems.

A good video put out by ATTRA not only addresses crop rotation but weed control in doing it. Youtube video  Organic Crop Rotation: Conservation Benefits

Additional standards (material/information) for crop rotation section IV eFOTG Conservation Practices,
·        Alley Cropping (311),
·         Conservation Crop Rotation,
·        Cover crop Standard (340)

No comments:

Post a Comment