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Advancing Cover Crop Systems in Ontario – Focus on Soil Nutrients (N+P), Soil Health, Insects and Nematodes

OSCIA Tier Two Project

– Adam Hayes, Soil Management Specialist, OMAFRA

Year 2 Update of the 3 Year Project:

Multi Species Cover Crop Mixtures – in year one three small plot, intensive sites, were setup in Winchester, Ridgetown and Thamesville following wheat. All three sites had four reps with 22 different treatments. Treatments included a no cover check plot and 21 different cover crop mixes ranging from 2-14 species per mix. Additional to the three small plot sites, eleven satellite locations were established. These locations were strip trial plots with varying number of treatments and replications. Three similar plots were set up this summer after wheat.

Cover Crop Nitrogen Credit: The two nitrogen trial sites consist of field-scale strips with check (no cover crop) strips and strips of a cover crop mixture.  In order to isolate the nitrogen credit, a no cover crop check versus planting a cover crop mixture replicated 4 times was established. At the three small plot locations (Ridgetown, Thamesville and Winchester) total dry matter varied between 790-13875 lbs/ac. While at the eleven satellite locations total dry matter varied between 852-9625 lbs/ac. N applic at demo farm 2016 DSCF5088

Comparing across all treatments at the three small plot locations there was no significant difference in cover crop biomass dry weight between mixes with 3, 6, 9, or 10+ species however biomass dry weight in all cover crop plots was significantly higher than the no cover plots where volunteer wheat was the only species present.



Counts of species present in each treatment were also performed at the small plot locations (see photo at right).  In the spring of 2016, corn will be planted with five nitrogen rates to determine the nitrogen credit if any from the cover crop. One of the plots was lost so one will go to harvest this fall. Only one was planted in year 2.

Phosphorus: To date, a laboratory experiment has been conducted to examine the effects of cover crop species, type of freeze-thaw cycle, and the effects of termination prior to freezing on phosphorus export. These variables were tested for both phosphorus and nitrogen release. The field component of the phosphorus study will begin in the fall of 2016. At present, a series of field trials have been initiated on the University of Waterloo campus to determine an appropriate set of instrumentation for the leaching studies.

Insects: In the spring of 2015 sampling was performed in cover crop trials at seven locations to assess insect presence. These locations had strips of cover crop mixtures and within each two 0.25m2 holes were dug to a depth of 6”. The soil from these holes was examined by hand and all insects were placed in 95% ethanol and transported to the lab for identification. Millipedes made up the vast majority of the specimens found at the research sites. Millipedes can be considered both beneficial for breaking down organic matter and as pests, choosing to feed on crop seeds if conditions are ideal.

All seven locations had wireworms present at varying degrees of infestation. In year 2 pitfall traps were installed in several cover crop plot fields. Slug traps were also used.

SCN: With the increase in cover crops usage and interest in field crops it is important to understand if the cover crop species listed are inadvertent hosts for plant diseases and nematodes. In 2015, the same  cover crop species were planted in two locations (Highgate and Rodney) and accessed for suitability as a host for Soybean cyst nematode (SCN – Heterodera glycines) and root lesion nematode (RL- Pratylenchus penetrans) as well as the fungal disease sudden death syndrome (SDS- Fusarium virguliforme). At both locations (Highgate and Rodney), SCN reproduction was only observed on the broadleaf legume, crimson clover and at very low levels.  Roots were also processed to determine the average number of SCN larvae (juveniles) in the root.  Hairy vetch had the highest number followed by red clover.  The other clovers (sweet yellow, crimson and white) along with faba beans had the low levels of SCN larvae in the roots.  No SCN larvae were found associated with brassicae and grass cover crop roots. Although these results from this one year study show low or little risk for SCN reproduction it is important to note that broadleaf legume cover crop species such as hairy vetch, red clover, field pea, crimson clover, white clover, sweetclover and faba beens have been reported to be SCN hosts.  Besides planting SCN resistant varieties growers who use these species should routinely take a SCN nematode sample to note changes in nematode population levels. Root lesion nematodes were detected in all 26 cover crop species ranging from a high of over 15,000 nematodes per gram of root to a low of 75 nematodes per gram of root.   Seven cover crop species had root lesion numbers averaged above 1000 nematodes per gram of root.  The highest by far was Sunn Hemp which was over 15,000 nematodes/g root followed by Field peas (7352) and Faba Beans 4072).  Four other cover crop species hairy vetch, white clover, red clover and oriental mustard ranged from 1921 to 1429 root lesion nematodes per gram of root whereas the remaining 19 cover crop species were all below 1000 nematodes per gram of root. This was repeated in year 2.Field View CC




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Ottawa Rideau SCIA

Serving Lanark, Leeds, Grenville, Frontenac, Renfrew & Ottawa-Carleton

Heartland Soil and Crop Improvement Association

Representing farmers in Huron, Perth, Waterloo and Wellington Counties.

Golden Horseshoe Soil & Crop Improvement Association

The volunteer organization representing the Ontario Soil & Crop Improvement Association (OSCIA) members in the counties/regions of Brant, Haldimand, Halton, Niagara North, Niagara South, Norfolk, Peel and Wentworth.

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