H. W. Cutforth

Canola and mustard response to short periods of temperature and water stress at different developmental stages

Seed yield of Brassica crops in semiarid environments can be increased by minimizing the crops’ exposure to high temperature and water stress that often occurs during the growing season. A growth chamber study was conducted to determine the effect of short periods of high temperature and water stress at different developmental stages on seed yield and yield components of Brassica crops. Two canola-quality Brassica juncea ‘PC98-44’ and ‘PC98-45’, a Brassica napus canola ‘Quantum’, and a B. juncea oriental mustard ‘Cutlass’ were grown under 20/18°C day/night temperatures with photoperiod of 16/8 h light/dark. High (35/18°C) and moderate (28/18°C) temperature stress was imposed for 10 d during bud formation, flowering, and pod development. Low (90% available water) and high (50% available water) water stress was imposed in combination with the temperature treatments. On average, the 35/18°C stress reduced main stem pods by 75%, seeds pod-1 25%, and seed weight 22% from the control. Seed yield per plant was r...

Response of three Brassica species to high temperature stress during reproductive growth.

The effect of short periods of high temperature stress on the reproductive development and yield of three Brassica species were studied in a growth chamber experiment conducted for 2 yr. Two genotypes from Brassica juncea L. and one each from B. napus L. and B. rapa L. were grown under day/night temperatures of 20/15 °C till early flowering or early pod development, subjected to high temperature stress of 28/15 °C or 35/15 °C for 7 d and then allowed to recover at 20/15 °C. Species differed in optimum temperatures, with B. juncea and B. rapa having higher optimum temperature than B. napus. Dry matter was unaffected by moderate temperature stress, while it was reduced by high temperature stress. The 35/15 °C treatment was injurious to reproductive organs at different developmental stages of all three species. High temperatures at flowering affected yield formation more than high temperature at pod development. On the main stem, mean seed yield reduction due to heat stress was 89%, but partial compensation ...

Yield and water use efficiency of pulses seeded directly into standing stubble in the semiarid Canadian Prairie

In semiarid climates, appropriate management of the previous crop stubble in combination with seeding method is important to improve growing conditions for the subsequent crop. To determine the effects of standing stubble of various heights on the microclimate and on the growth and yield of pulse crops, we seeded desi chickpea (Cicer arietinum L. “Cheston”), field pea (Pisum sativum L. “Grande”), and lentil (Lens culinaris L. “Laird”) directly into cultivated, short (15 to 18 cm), and tall (25 to 36 cm) spring wheat (Triticum aestivum L.) stubble. Standing stubble changed the microclimate near the soil surface by reducing soil temperatures, solar radiation, wind speed, and potential evapotranspiration throughout the life cycle of these crops. Microclimate effects were much more pronounced for tall versus short stubble. The three pulses responded similarly to increasing stubble height. Vine length increased as stubble height increased, but the plants did not stand more erect. However, there was a tendency ...

Water use efficiency and water and nitrate distribution in soil in the semiarid prairie: Effect of crop type over 21 years

In the semiarid prairie, available water is the most limiting and nitrogen the second most limiting factor influencing crop production. Although numerous studies have been conducted on the effect of management practices on water use efficiency (WUE), most have concentrated on monoculture wheat, the major crop grown in the region. Even those studies dealing with other crop types have mostly been short-term in nature. But precipitation is so variable in amount and distribution that such an assessment is best conducted in long-term experiments. We used the results of a 21-yr experiment, conducted in the Brown soil zone at Swift Current, Saskatchewan, to determine the influence of crop type on WUE, and used the distribution of water and NO3-N in the soil, and N uptake by the crop to assist in interpreting these results. Four crop rotations were compared: summer fallow-wheat-wheat (F-W-W), F-flax-W (F-Flx-W), continuous wheat (Cont W) and wheat-lentil (W-Lent). All received N and P fertilizer based on soil tes...

Adaptation of alternative pulse and oilseed crops to the semiarid Canadian Prairie: Seed yield and water use efficiency

Diversification and intensification of the cropping systems in the traditional wheat-fallow area of the semiarid Canadian prairie is necessary to improve sustainability. Selection of alternate crops to include in cropping systems requires information on production risks with different climate regimes. To understand water use/yield relationships of alternate crops, three pulse crops (leguminous grain crops) [chickpea (Cicer arietinum L.), pea (Pisum sativum L.) and lentil (Lens culinaris Medik.)], three oilseed crops [canola (Brassica napus L. and B. rapa L.) and mustard (B. juncea L.)], and one cereal crop [wheat (Triticum aestivum L.)] were studied under varying water regimes: during 1996–1998 under well-watered, rainfed, imposed drought conditions, and in 2001 under rainfed conditions. Generally, the relative ranking between crops for water use was maintained across water regimes, such that the crops separated into three general groups of water users (high: wheat, B. napus, mustard; medium: chickpea, B....

Diversifying crop rotations with pulses enhances system productivity.

Agriculture in rainfed dry areas is often challenged by inadequate water and nutrient supplies. Summerfallowing has been used to conserve rainwater and promote the release of nitrogen via the N mineralization of soil organic matter. However, summerfallowing leaves land without any crops planted for one entire growing season, creating lost production opportunity. Additionally, summerfallowing has serious environmental consequences. It is unknown whether alternative systems can be developed to retain the beneficial features of summerfallowing with little or no environmental impact. Here, we show that diversifying cropping systems with pulse crops can enhance soil water conservation, improve soil N availability, and increase system productivity. A 3-yr cropping sequence study, repeated for five cycles in Saskatchewan from 2005 to 2011, shows that both pulse- and summerfallow-based systems enhances soil N availability, but the pulse system employs biological fixation of atmospheric N2, whereas the summerfallow-system relies on ‘mining’ soil N with depleting soil organic matter. In a 3-yr cropping cycle, the pulse system increased total grain production by 35.5%, improved protein yield by 50.9%, and enhanced fertilizer-N use efficiency by 33.0% over the summerfallow system. Diversifying cropping systems with pulses can serve as an effective alternative to summerfallowing in rainfed dry areas.

Stubble management and microclimate, yield and water use efficiency of canola grown in the semiarid Canadian prairie

Standing stubble traps snow and creates a favorable microclimate, which increases yields in wheat (Triticum aestivum L.) and pulses [chickpea (Cicer arietinum L.), field pea (Pisum sativum L.) and lentil (Lens culinaris L.)]. 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 four seasons (1999 to 2002) to assess the effect of stubble management on the microclimate, water use and seed yield of argentine canola (Brassica napus L. ‘Arrow’) in the semiarid prairie surrounding Swift Current. Tall (30 cm), short (15 cm) and cultivated stubble treatments were deployed in fall and in spring. An additional tall stubble treatment with extra fertilizer N (application rate recommended for the Black soil zone in the subhumid prairie) was included to assess the role of fertilizer in canola response to stubble management practices. The differences in wind velocity, soil temperature and solar radiation ...

Early seeding improves the sustainability of canola and mustard production on the Canadian semiarid prairie

Canola and mustard production is increasing in the semiarid prairie and seeding date affects the heat and water stress experienced by those crops. We conduced a 4-yr field study on the effect of fall (November with expected spring germination), early spring (late April) and late spring (late May) seeding on the growth of two cultivars representing two different canola species (B. napus L. ‘Arrow’ and B. rapa L. ‘Sunbeam’) and of two cultivars representing two different mustard species (B. juncea L. Coss. ‘Cultass’ and Sinapis alba L. ‘Pennant’). Generally, all cultivars from the four different species responded similarly to seeding dates. Flowering during a period of less water stress increased grain yields so years with good moisture availability in spring (1999 and 2000) favored earlier seeding (fall and early spring) while a drier spring with moister summers (2001 and 2002) favored spring seeding. Fall seeding resulted in lower plant populations than spring seeding. Early spring seeding was most freque...

Fertilizer N response and canola yield in the semiarid Canadian prairies

Canola is a viable crop when grown under fallow in the semiarid prairie, but is also grown in longer rotations, most often no-till seeded into standing stubble. Selecting the proper N fertilizer rate is a very challenging production decision, but most of the available nitrogen response for canola has been derived for the more subhumid parts of the Canadian prairies. We developed simple quadratic equations to describe the yield relationship for stubble-seeded open-pollinated and hybrid canola in the semiarid Canadian prairie. These relationships indicate that hybrid canola produced higher grain yields at all fertilizer rates and had optimum N fertilizer rates about 50% higher than those for open-pollinated canola. Key words: Canola, fertilizer N, grain yield, water use, semiarid prairie

Long-term changes in the frost-free season on the Canadian prairies

The climate of the prairies has warmed over the past century, especially during late winter and early spring. Some regions of the prairies have warmed faster than others. Climate change has been documented to affect living systems in North America, such as promoting earlier phenological development and longer growing seasons. We examined weather records gathered at several long-term weather-recording sites across the agricultural regions of the Canadian prairies for evidence of trends in last spring frosts, first fall frosts, and frost-free durations. During the latter half of the 20th century, the trends were towards earlier last spring frost dates and towards longer frost-free seasons in the agricultural regions of the Canadian prairies. Across most of the prairies the trends towards later first fall frost dates were smaller and generally not significant. The largest changes have occurred in the central and northern agricultural regions of Alberta, whereas the least change occurred over much of southern...