Cutforth: Seeding Management to Increase and Stabilize Canola Production in the Semiarid Prairie
Date: February 2002
Term: 4 years
Status: Completed
Researcher(s): Dr. Herb W. Cutforth, Dr. Sangamesh V. Angadi and Dr. Brian McConkey, Agriculture and Agri-Food Canada, Swift Current, SK
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: ADF, AAFC
Project Summary
Canola production in the semiarid prairie is susceptible to high temperature and water stress. Field experiments were conducted at Swift Current over 4 years from 1998 to 2001 to determine the effect of seeding management, stubble management and population densities on the productivity of canola and mustard in the Brown soil zone. The results of this study clearly indicate that simple and easy to implement technologies such as fall or early-spring seeding and seeding directly into tall standing stubble are successful technologies for growing canola and offer greater income stabilization and a better fit of canola as a crop for the Brown soil zone. The results also suggest that, as a general rule, a population of between 20-25 plants per square meter would be a reasonable threshold for re-seeding canola in the semiarid prairie.
In the semiarid Brown soil zone, water and temperature are the two major factors limiting crop productivity. Improving the economics of growing canola in this region requires adopting practices that promote more efficient use of water such as seeding into tall standing cereal stubble and seeding early to avoid heat and water stress during July and August. Field experiments were conducted during the 1998-1999, 1999-2000, and 2000-2001 crop years at the Semiarid Prairie Agricultural Research Centre at Swift Current to determine the effect of seeding management, stubble management and population densities on the productivity of canola and mustard in the Brown soil zone.
The main goals of this research were to: 1) compare yield and water use efficiencies of different canola and mustard species when seeded at different dates: late fall, early and late spring and of Argentine canola seeded into stubble of various heights: cultivated, short (15 cm high) and tall (>30 cm high) stubble; and 2) to determine the relationship between suboptimal plant populations and yield to determine the conditions under which re-seeding becomes advantageous. The secondary objective was to evaluate the heat balance sap flow system for measuring the real time water use of canola under varying environments.
Overall the results of this study clearly indicate that simple and easy to implement technologies such as fall or early-spring seeding and seeding directly into tall standing stubble are highly successful technologies for growing canola and offer greater income stabilization and a better fit of canola as a crop for the Brown soil zone. The low and nonuniform canola population performed better than expected because of the tremendous plasticity of canola. The results also suggest that, as a general rule, a population of between 20-25 plants per square meter would be a reasonable threshold for re-seeding canola in the semiarid prairie.
Alternate Seeding Dates Influence Adaptability of Brassica Species
Three open-pollinated Brassica species, B. napus (cv. Arrow), B. rapa (cv. Sunbeam) and B. juncea (cv. Cutlass) were seeded at three different seeding dates, late fall, early and late spring to determine the effect of fall and spring seeding on the growth and water use and seed yields.
The results show that fall and early spring seeding increased seed yield by >30% compared to late spring seeding, showing the value of early seeding to increase canola and mustard seed yields in the Brown soil zone. Generally, all three species responded similarly to seeding dates, with the efficiency of water use increasing with fall and early spring compared to late spring seeding. In the extremely dry year of 2001, the response of canola and mustard to seeding date was noticeably dependent upon the timing of rainfall events; however, the highest yield occurred when canola was seeded in early spring.
Stubble Management and Alternate Seeding Dates for Canola
Standing stubble traps snow and creates a favorable microclimate and generally, the taller the stubble the greater is the effect on microclimate and yield. A field study using farm scale seeding and harvesting equipment was conducted over three seasons (fall 1998 to summer 2001) to assess the effect of stubble management on the microclimate, water use and seed yield of canola at Swift Current. Tall (>30 cm), short (15 cm) and cultivated treatments were imposed in fall and in spring.
All plots received the recommended Brown soil zone fertilizer rate (70 kg/ha N , 24 kg/ha P2O5 and 22 kg/ha S) and one tall stubble treatment received 34 kg/ha extra fertilizer N to assess the role of fertilizer in canola response to seeding and stubble management practices. Canola cv. ‘Arrow’ was seeded in late fall (before freeze-up), early spring (last week of April) and late spring (third week of May). The differences in wind velocity, soil temperature and solar radiation reaching the soil surface indicate significant modification of the microclimate by tall compared to cultivated stubble.
Tall standing stubble modified the canola microclimate significantly by reducing wind speed at the 15 cm height, by cooling soil temperature at the 5 cm soil depth, and by reducing solar radiation reaching the soil surface. Tall stubble tended to have better crop establishment compared to cultivated stubble, although biomass at harvest and water use did not show any effect of stubble height. Averaged across the three seasons, tall stubble and tall stubble+extra fertilizer significantly increased seed yield by 21 and 40%, respectively, compared to the average yield of all the cultivated plots.
Seeding dates interacted with stubble treatments and yield improvement with tall stubble and tall stubble+extra fertilizer were higher in the fall compared to late spring. Therefore, seeding into tall stubble is a potential management practice to increase canola productivity in the semiarid prairie.
Canola Plant Population and Yield Formation
Canola compensates seed yield over a wide range of populations due to a high degree of plasticity. Seed yield of canola is a function of population density, number of pods per plant, number of seeds per pod and the individual seed weight. However, little is known about canola response to plant density in the semiarid prairie.
The objectives of this experiment were to determine (1) how canola maintains seed yield over a range of population densities, (2) how plant population affects yield component distribution on the plant, and (3) identify the threshold population when reseeding should be considered. Argentine canola cv. Arrow was seeded in uniform populations of 80, 40, 20, 10 and 5 plants per square meter and nonuniform populations of 40, 20 and 10 plants per square meter.
The canola was seeded at a rate of 12 kg/ha and thinned to required plant populations at the 2 to 4 leaf stage.
The results show that reducing population by 50% from 80 to 40 plants per square meter and non-uniform plant stand had no effect on seed yield. Further, under good moisture conditions, decreasing plant population to 20 plants per square meter reduced seed yield by <20%. To restrict yield reduction to about 30% under very dry conditions, a population of at least 25 plants per square meter is required. Using results from the seeding date experiment showing that seeding in late spring reduced seed yield by >30%, researchers recommend a population of 20-25 plants per square meter would be a reasonable threshold for re-seeding canola in the semiarid prairie.
Measurement of Water Use by Canola with Sap Flow Gauges
Sap flow gauges using heat balance have been reliable for measuring real-time transpiration in a number of crops. However, information on the accuracy of sap flow gauges in canola is lacking. Therefore, the objectives of this research was to determine the accuracy of sap flow gauges using heat balance for measuring transpiration in canola, and to use sap flow gauges to quantify canola response to weather parameters like light and temperature.
Sap flow measurements were made during 1999 and 2000 in growth chamber, greenhouse and field experiments at AAFC in Swift Current. Brassica napus cv. ‘Quantum’ was used for indoor studies while, cv. ‘Arrow’ was used for the field study.
The results indicated a strong relationship between sap flow and transpiration, confirming the sap flow system was useful for quantifying transpiration in canola. Overall, sap flow in canola was strongly related to daily solar radiation. The heat-balance sap flow system will be a useful tool for measuring real-time water use in agronomic and physiologic studies of crop growth and development.
Scientific Publications
Angadi, S.V., Cutforth, H.W., Miller, P.R., McConkey, B.G., Entz, M.H., Brandt, S.A. and Volkmar, K.M. 2000. Response of three Brassica species to high temperature stress during reproductive growth. Can. J Plant Sci. 80: 693-701.
Angadi, S.V., Cutforth, H.W. and McConkey, B.G. 2003. Determination of water use and water use response of canola to solar radiation and temperature using heat balance sap flow gauges. Can. J. Plant Sci. 83:31-38. Angadi, S.V., Cutforth, H.W., McConkey, B.G. and Gan, Y. 2003. Yield adjustment by canola grown at different populations under semiarid conditions. Crop Sci. 43: 1358-1366.
Angadi, S.V., Cutforth, H.W., McConkey, B.G. and Gan, Y. 2004. Early seeding improves the sustainability of canola and mustard production on the Canadian semiarid prairie. Can. J. Plant Sci. 84: 705-711. Cutforth, H.W., Angadi, S.V. and McConkey, B.G. 2006. Stubble management and microclimate, yield and water use efficiency of canola grown in the semiarid Canadian Prairie. Can. J. Plant Sci. 86:99-107.