Organic Crop Production Basics

Organic crop production is a system of farming based on ecological principles. One formal definition states that, "Organic farming seeks to create ecosystems that achieve sustainable productivity and provide control of pests through a diverse mix of mutually-dependent life forms, through recycling of plant and animal residues, and through crop selection, crop rotation, water management and cultivation. Soil fertility is maintained and enhanced by a system which optimizes soil biological activity as the means to providing nutrients for plant and animal life as well as to conserve soil resources".

A crop cannot be marketed as "Certified Organic" in Manitoba until the land on which it is grown has been free of synthetic fertilizers and pesticides for at least three years prior to crop harvest. The third harvest on the land can therefore be recognized as an organic product.

The primary challenges in an organic crop production system include:

1. Fertility
2. Weed Management
3. Insect Management
4. Disease Management
5. Soil Conservation

Fertility

Soil testing on a regular basis is an important tool in the management of an organic cropping system. As well as providing the grower with an approximate level of nutrients in the soil, the soil test can help measure the benefit of various agronomic practices over a number of years.

There are several products and practices that will supply nutrients organically:

• application of composted animal manure
• green manure plow-downs
• including legumes in the crop rotation
• alternating high and low-nutrient demand crops
• alternating deep and shallow-rooted crops
• summerfallow
• use of certain fertilizers (from the list of permitted inputs)
• use of certain microbial inoculants (from the list of permitted inputs)

Weed Management

Effective weed management depends on a thorough understanding of the biology and growth habit of the species in question. In most cases, a combination of a number of cultural and preventative practices will be required to effectively deal with weeds:

• field and crop sanitation
• crop rotations
• crop competition (which includes the variables of crop selection, seeding date, seeding rate, row spacing, seeding depth and plant nutrition)
• both out-of-crop and in-crop tillage
• use of plants with beneficial allelopathic effects
• mowing and burning
• biological controls

Insect Management

As with weed management, successful insect control will depend on incorporating a number of control strategies together:

• diverse crop rotations
• field and crop sanitation
• weed management
• seeding date and seeding rate
• management of summerfallow and stubble
• seeding trap strips
• balanced soil nutrition
• resistant cultivars
• biological controls
• insect hormones

Disease Management

Plant disease control measures are aimed at reducing or eliminating one of the three factors involved in disease development: an infectious pathogen, a susceptible host and a suitable environment. Not only do these factors interact, but disease control strategies also must be woven together with management methods to address weed, insect and other production concerns.

Considerations in disease management should include:

• rotation of susceptible and resistant crops
• the use of resistant cultivars
• field sanitation: managing disease-infected straw, stubble, chaff and volunteer plants
• seed sanitation: importance of uncracked and disease-free seed
• planting dates, rates and depth
• maintaining balanced soil nutrient levels, including both macronutrients and micronutrients
• the use of livestock manure to stimulate higher populations of soil microorganism
incorporation of green manure cover crops

Soil Conservation

As in other farming systems, the challenge in the organic system is to employ soil conservation practices that are best adapted to each particular farm. Such practices that use herbicides are not an option, although attempts are made to not use tillage any more often than in conventional systems. Therefore, the organic crop producer may need to use a combination of effective soil conservation measures. These may include:

• optimizing the use of crop residues to replenish soil organic matter and improve soil properties such as water infiltration, water storage, and particle aggregation.
• limiting tillage depth, speed and the number of operations to conserve crop residue and soil moisture.
• appropriate stubble height
• direct seeding
• extending crop rotations to reduce summerfallow
• using wind barriers such as annual crops, perennial grasses and shelterbelts in crop or summerfallow situations.
• strip cropping at an angle perpendicular to the prevailing wind direction
• cover crops to protect the soil from wind and water erosion during certain vulnerable periods
• incorporating green manure to improve soil quality
• effective use of animal manure

 

• Organic Agriculture Web Links

General Information on Crop Production | Soil Quality

For further information, contact your GO representative.