b'COVER CROP CORNERDOES YOUR SOIL HAVE GOOD AGGREGATE STRUCTURE? COVER CROPS CAN HELPMODERN AGRONOMIC PRACTICESoften hinder theduring the growing season. These cover crops natural establishment of stable soil aggregates.release root exudates, nurturing a liquid carbon However, cover crops offer a powerful solution. pathway vital for microbial growth, thereby During their growth phase, cover crops releasepreserving aggregate structure. root exudates that nurture soil biology, creating a harmonious environment alongside water, air and shelter. The ingenious utilization of theseDO YOUR OWN AT-HOME SOIL root exudates by microbial communities leadsAGGREGATE TESTKevin Elmy to the development of granular habitats known Elmy is founder of Cover Crops Canada. His bookas root rhizosheaths. These structures provideThe Slake TestCover Cropping in Westernaeration, retain moisture and safeguard microbes.Materials Needed:Canada is availableRemarkably, nitrogen-fixing microbes foster through Friesen Press,anaerobic conditions, facilitating nitrogen fixa-Air-dried soil aggregateAmazon, and digitallytion.Container of waterthrough Apple Books, 2-to-4 millimetre mesh holderKindle, and Google Play.As main crops shift into their reproductive For more info on Coverphase, they reduce exudate release, focusing Crops Canada visitcarbon on growth. These mature exudates areInstructions:covercrops.ca more resilient to microbial breakdown, benefiting1.Prepare the Soil Aggregate: subsequent plant generations upon seed disper- Ensure that you have an air-dried aggregate ready sal. However, a decline in microbial activity andfor the test. The aggregate should be as dry as liquid carbon availability prompts soil biology topossible to achieve accurate results.consume the binding agents that form soil aggre- 2. Assemble the Equipment: gates, weakening them.To counteract this aggregate degradation,Set up your testing area with a container of water maintaining cover crops in their vegetativeand the 2-to-4 millimetre mesh holder. This will be stage throughout the growing season becomesused to hold the soil aggregate.3. Place the Soil Aggregate: pivotal. This practice sustains a steady influx of liquid carbon, which fuels microbial expansion.Gently place the aggregate into the mesh holder. When the season concludes, microbes reinforceMake sure its evenly spread out within the holder.the aggregates formed during growth by adding4.Lower into Water: more binding agents. This strengthens aggregates,Carefully lower the mesh holder into the container ensuring resistance against water-induced disinte- of water. Submerge the aggregate completely.gration while promoting gas exchange. 5. Observe the Reaction:The cover crops development of healthyWatch closely how the soil aggregate reacts to rhizosheaths around growing roots generatesbeing placed in the water. Look for the following micro and macropores within aggregates. Thesesigns:pores facilitate swift water penetration, effectiveDesired Outcome: The water should enter air exchange, and water retention during dry peri- the aggregate freely, and you may observe ods while creating air pockets during saturation.air bubbles being released from within the When cover crop roots decay, the rhizosheath envelopes the macropores, further contributing toaggregate. The soil aggregate should maintain aggregate stability. its structure and integrity.This process poses more challenges in sandy Undesired Outcome: If the soil aggregate startssoils and arid climates, making the role of coverto break apart or disintegrate (slake) upon crops even more critical. Nevertheless, the centralcontact with water, it indicates low aggregate principle remains unwavering: ensuring thestability.presence of cover crops in their vegetative stage SEPTEMBER 2023GERMINATION.CA 37'