Trial Report Summary

Yellow Pea Response to Preceding Crop, Residue Management, and P Fertilizer Placement (Establishment Year)

Crop Type(s):
Peas
Centre(s):
PCDF
Year(s):
2020
Collaborators(s):

Kristen MacMillan – Soybean and Pulse Agronomy and Cropping Systems Research
Lab, University of Manitoba

Objective(s):

Determine the effect of preceding crop, residue management and P fertility strategy, and their interactions, on pea establishment, weed community, disease incidence, yield and seed quality.

Project Findings:

In 2020, spring wheat and canola crops were established to provide the residue treatments for the 2021
pea test.

Background:

In Manitoba, 38% of pea acres are grown on wheat stubble and 20% on canola stubble [Manitoba
Agricultural Services Corporation (MASC) 2010-2015]. The yield impact of preceding crop on pea yield is
not currently known despite some obvious agronomic concerns. Crop rotation data from MASC (2010-
2015) points to some of these risks by showing that the relative yield of pea grown on wheat stubble is
103% compared to 96% for peas grown on canola stubble. Canola is a non-mycorrhizal crop and a host
to Sclerotinia white mould. Peas are also susceptible to white mould and are a mycorrhizal crop,
therefore, may be negatively affected by reduced AMF populations and increased sclerotinia risk
following canola stubble. Starter P is commonly recommended in fields with low soil test levels. We aim
to investigate if there is an interaction between field pea response to P fertilizer and preceding stubble
type arising from the mycorrhizal and non-mycorrhizal crops. Little research has been conducted on P
fertilizer strategy in field pea and strategies vary widely among farmers. In an informal Twitter poll in
August 2019, the majority of farmers apply P fertilizer as starter in the seed row (44%) followed by side
band or mid placement (26%), seed row plus side band or mid row (14%) and none (16%). According to
the 2015 fertilizer use survey, only 45% of western Canadian farmers are applying P, primarily in the
seed row (44%) and at an average rate of 19 lbs P205/ac. Yield response to 25 kg ha-1 of starter P has
been documented, but no work is currently available on P fertilizer placement. Overall, there are fewer
agronomic risks associated with seeding peas into wheat stubble. Peas are also tolerant to early seeding into cool soil and present an opportunity for reduced or rotational no-till systems in regions of Manitoba where tillage is common practice

PDF:

Entire findings are available by downloading the report PDF.

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