Download Optimizing Seedling Establishment of Late-Fall

Optimizing Seedling Establishment of Late-Fall Seeded Canola in the
Water-Limited, Heat and Drought Stressed Environments
Yantai Gan, Agriculture and Agri-Food Canada (AAFC) Swift Current, SK; B. Elliott,
AAFC Saskatoon SK, K. Topinka, Alberta Agriculture, Food and Rural Development,
Edmonton AB; S.V. Angadi and C.L. McDonald, AAFC, Swift Current SK, Project
Code: CARP 2000-23
Final Report: March 2003
Low available water, high heat and drought stresses are factors limiting canola
productivity in the Brown soil zone of the Canadian prairies where conventional
canola has not traditionally been grown. Recent advances in seeding technology have
provided producers with opportunity to grow canola in this dry area. The objective of
this research is to determine the effects of seed vigour, seed coating and seeding
technique on crop establishment and seed yields for fall-seeded and spring-seeded
canola in the dry Brown soils of the prairies. On average, canola seeded in the spring
produced higher plant populations and greater seed yields than fall-seeded crops and
shallow seeded crops performed and yielded the best.
Low available water, high heat and drought stresses are factors limiting canola
productivity in the Brown soil zone of the Canadian prairies where conventional canola
has not traditionally been grown. Recent advances in seeding technology (i.e., late-fall
seeding with polymer coating) have provided producers with opportunity of growing
canola in this dry area. Seeding
canola in the late-fall may allow
the crop to use the early-spring
soil moisture effectively because
late-fall seeded crop often
emerges from the ground soon
after the soil warms up. With its
early establishment and growth,
fall-seeded canola crop usually
flowers 2 to 3 weeks earlier than
spring-seeded canola. The early
flowering allows canola plants to
avoid or reduce the mid-summer
heat stress, thus increasing yield
potential. However, canola seeded in the late-fall normally germinates and emerges
under cold soil conditions the following spring, thus, poor emergence and thin plant
establishment often occurs.
The objective of this research is to determine the effects of seed vigour, seed coating
and seeding technique on crop establishment and seed yields for fall- and spring-seeded
canola in the dry Brown soils of the prairies. Two field experiments were conducted at
Swift Current in 2000 and 2001 and a third experiment conducted at Ellerslie, Alberta in
2001.
In two of the experiments, three different seedlots were planted in the fall and the
following spring in both years 2000 and 2001. The three seedlots were: (1) seeds
harvested from early spring-seeded crops (ES), (2) seeds harvested from late springseeded crops (LS) and (3) seeds harvested from late fall-seeded crops (LF) the previous
year. All three seedlots were coated with a polymer “Extender” for fall seeding, and
were compared with non-coating treatments. In the spring seeding, only non-coated
seeds were used. The three seedlots were planted at half inch (12mm), one inch
(24mm), and one and a half inches (38mm) seeding depths. The experiment at Ellerslie
was identical to the one at Swift Current, except that all fall-seeded treatments used
only coated seeds at Ellerslie. In the second experiment, canola with high, medium, and
low seed vigour was planted in the fall and then the following spring in both 2000 and
2001 at Swift Current. Fall seeding occurred between October 30 and November 3 and
spring seeding between April 23 and May 15.
Fall vs Spring-Seeding
On average, canola seeded in the spring produced a plant population density that was
28% higher at Swift Current and 270% higher at Ellerslie than the plant densities
obtained from the fall-seeded crops. At Swift Current in 2000, fall-seeded canola
flowered 9 days earlier and matured 10 day earlier than spring-seeded canola and the
spring seeded canola produced an average of 8% higher seed yield than fall-seeded
canola at Swift Current. At Ellerslie in 2001, there was no difference in flowering and
maturity and the spring-seeded canola produced a seed yield that was more than
double the seed yield of the fall-seeded canola. Lower seed yields with fall-seeded
canola at both sites were mainly due to weather conditions and poor plant
establishment (Table 3).
Effect of Seeding Depth
When comparing the effect of seeding depth, the results were very consistent across
the study. Canola planted at half inch (12mm) significantly increased plant counts and
shortened the time of flowering and maturity. Shallow seeded canola increased seed
yields by 17 to 20% at Swift Current in 2002, 42 to 55% at Ellerslie in 2000 and over 80%
Swift Current in 2002. Although growers rarely seed at the deeper depths, the actual
seed anchoring depth is normally deeper than planned due to a furrow close-up or the
uneven soil surface in the field. These results indicate that a depth control in canola
production plays a significant role in improving the seed yield and returns in the dry
Brown soil zone (Figure 5).
Table 3. Agronomic characteristics of spring- and fall-seeded canola at Swift Current and
Ellerslie in 2000, 2001, and 2002.
Year/Site
Seeding
date
Plant
density
(plants m-2)
Seed yield
Date of
Date of
80%
% over fallmaturity (kg ha-1)
flowering
seeded
2000
Spring
63
July 9
Aug 4
1456
+8
Swift Current
Fall
49
June 30
July 24
1347
0
2002
Spring
7
July 15
Aug 10
681
-17
Swift Current
Fall
8
July 11
Aug 8
824
0
2001
Spring
72
July 11
Aug 31
2826
+139
Ellerslie
Fall
19
July 10
Aug 31
1185
0
Plants were not established at Swift Current in 2001 due to extremely dry spring
conditions.
Field Performance of Canola with Different Seed Vigour
Results of field experiments showed a consistently higher plant population density for
canola derived from a higher seed vigour lot predetermined by tests in the laboratory.
This trend of higher seed vigour resulting in higher plant count was consistent when the
seed was planted either in the spring or the fall. Seed vigour, however, did not have an
impact on the time of flowering or plant maturity and did not significantly affect seed
yields at either Swift Current or Ellerslie.
Effect of Different Seedlots
Results showed that ES seed produced a slightly higher plant density than the two other
seedlots. At Swift Current, there was basically no difference in seed yields for the canola
crops grown from the three different seedlots regardless of seeding time. However, at
Ellerslie, the canola crops grown from the ES seed produced 24% higher seed yield than
the crops grown from the LS seed when seeded in the fall in 2001. Similarly, the crops
grown from the LF seed produced 18% higher seed yield than the crop grown from the
LS seed when seeded in the fall. When the three seedlots were seeded in the spring,
they did not differ in seed yield. These results indicate that the ES and LF seeds may
produce a more vigorous plant and higher seed yields than the LS seed under stressful
growing conditions such that encountered in the fall-seeded situation of 2001. When
growing conditions become favorable for canola emergence and early growth, then the
differences among the three seedlots diminish.