Articles

Principles of Crop Production

Author(s): David J. Connor

Summary: Plants are autotrophic and therefore they fix the energy of the sun and manufacture food from simple inorganic substances for almost all other organisms through photosynthesis. Crop plants have a wide range of development and growth responses to sunlight, day length, temperature, nutrients, and water supply. Farmers do not, however, choose plants as crops for optimum adaptation to individual environments, but those that are preferred food, as in developing countries, or to meet market requirements, including global trade.

_{Citation: Connor, D. J. Principles of Crop Production. 2013. Prairie Soils and Crops 6:1-6. [http://www.prairiesoilsandcrops.ca]}

The Physiology of Plant Hormones in Cereal, Oilseed and Pulse Crops

Author(s): Leonid V. Kurepin, Jocelyn A. Ozga, Mohammad Zaman and Richard P. Pharis

Summary: Plant hormones regulate virtually all aspects of plant growth and development, as well as plant responses to biotic and abiotic signals. Herein, we discuss three hormone groups, gibberellins, auxin and ethylene. These plant hormones influence seed germination, root, stem and leaf growth, flowering, and fruit and seed growth. In so doing, the hormone groups often interact with each other and with the plant’s environment. This review discusses the regulatory roles that these three plant hormone groups play in the physiology of cereal, oilseed and pulse crops and also discusses the usefulness of applications of hormones, and of other plant growth regulators. Additionally, it discusses the potential uses of plant growth promoting rhizosphere (root-zone) microorganisms (PGPRs) in order to obtain yield improvement, or to alleviate abiotic stress.

_{Citation: Kurepin, L. V., Ozga, J. A., Zaman, M. and Pharis, R. P. The Physiology of Plant Hormones in Cereal, Oilseed and Pulse Crops. 2013. Prairie Soils and Crops 6:7-23. [http://www.prairiesoilsandcrops.ca]}

Dynamics and Management of Crop-Weed Interference

Author(s): Eric R. Page and Chris J. Willenborg

Summary: Weed management is one of the most critical factors influencing crop yield. By providing a window of weed-free growth early in the growing season, the size advantage that crop seedlings have over weeds can be utilized to reduce the intensity of direct competition for resources at the stages of crop development when yield is being determined. The goal of this review is to provide an overview of the process of crop-weed interference and explore avenues for improving weed control through the use of integrated weed management (IWM) strategies.

_{Citation: Page, E. R. and Willenborg, C. J. Dynamics and management of crop-weed interference. 2013. Prairie Soils and Crops 6:24-32. [http://www.prairiesoilsandcrops.ca]}

Herbicide-Resistant (HR) Crops in Canada: HR Gene Effects on Yield Performance

Author(s): Hugh J. Beckie

Summary: Herbicide-resistant (HR) crops have been genetically modified through gene insertion or mutation to resist a specific herbicide or herbicide class. Since the first HR crop, triazine-HR canola, was introduced in Canada in 1981, several HR crops are now commonly grown. In this paper, the effect of the HR gene(s) on cultivar performance, primarily yield, is reviewed. Although some of the earliest-introduced HR crop cultivars suffered a yield penalty, currently grown cultivars often have similar or better yield performance than non-HR cultivars because of intensive breeding efforts by the private sector.

_{Citation: Beckie, H. J. Herbicide-Resistant (HR) Crops in Canada: HR Gene Effects on Yield Performance. 2013. Prairie Soils and Crops 6:33-39. [http://www.prairiesoilsandcrops.ca]}

Principles and Crop Yield Response To Root-Zone Salinity

Author(s): Harold Steppuhn

Summary: Agricultural salinity stems from the concentration of salts dissolved in soil waters. It is caused by subsurface hydrologic processes and can seriously affect some 20 million hectares across the Canadian Prairies. Although rootzone salinity reduces crop yield, some crops tolerate saline rooting environments better than others. A Salinity- Tolerance-Index specifies the degree of tolerance and yield maintenance for each crop. The salinity causing a 50% product loss (C50) and an average decline in relative crop yield with a unit increase in salinity (s) at and near C50 provides an abridged list of indices for Canadian crops.

_{Citation: Steppuhn, H. Principles and Crop Yield Response To Root-Zone Salinity. 2013. Prairie Soils and Crops 6:40-51. [http://www.prairiesoilsandcrops.ca]}

Nutrient Uptake and Metabolism in Crops

Author(s): Rigas E. Karamanos

Summary: Nutrient uptake is the mechanism by which plants capture all those elements that are essential for their growth. Metabolism is a series of chemical processes that occur within a plant that include either synthesis or breakdown of organic compounds. Nutrient uptake depends on a number of factors, including plant species, environmental conditions, nutrient supply and interrelationship among nutrients and between plant and soil, presence of microorganisms (e.g., fungi) in association with plant roots, etc. From a practical perspective, nutrient uptake determines the quantities of nutrients exported from a field via harvest and the requirements for their replenishment.

_{Citation: Karamanos, R.E. Nutrient Uptake and Metabolism in Crops. 2013. Prairie Soils and Crops 6:52-63. [http://www.prairiesoilsandcrops.ca]}

Photosynthetic Carbon Fixation and Crops

Author(s): R. A. Bueckert

Summary: Photosynthesis in higher plants is the process of transferring energy from light to a chemical form, and using it to capture or fix carbon dioxide (CO2) from the air into organic carbon. This article focuses on the last step, the photosynthetic fixation process, and starts by outlining the main features of C3, C4 and CAM plants. The main form of fixation is C3, found in most plants, and is catalyzed by the enzyme RUBISCO. The two other photosynthetic types are physiological adaptations to reduce photorespiration and to allow function in drought and stress. Photorespiration occurs in a low CO2 environment. Generally, C3 photosynthesis is an excellent compromise of photosynthetic efficiency with some photorespiration in temperate conditions. C4 photosynthesis minimizes photorespiration by splitting initial fixation into a 4-carbon acid step first, spatially separated from RUBISCO by leaf anatomical features, before later re-fixation in the C3 pathway.

_{Citation: Bueckert, R.A. Photosynthetic Carbon Fixation and Crops. 2013. Prairie Soils and Crops 6:64-77. [http://www.prairiesoilsandcrops.ca]}

Agricultural Meteorology and Crop Production on the Canadian Prairies: Solar Radiation, Temperature & Water

Author(s): Herb Cutforth

Summary: Agricultural meteorology is the study of how climate and weather impact agricultural systems. Solar energy, in the form of radiation, is the driver behind the regional distribution of climate and weather across the surface of the earth. After long time periods climate and weather become somewhat unique to a given region. Regional differences in, for example, solar radiation, temperature, precipitation, wind and humidity are identifiable and contribute to determining the agricultural practices that are practical and profitable in a given region. Although the energy budget and water balance vary across regions, there are basic principles for solar energy, temperature and water availability that can be applied independent of regions.

_{Citation: Cutforth, H. Agricultural Meteorology and Crop Production on the Canadian Prairie: Solar Radiation, Temperature and Water. 2013. Prairie Soils and Crops 6:78-86. [http://www.prairiesoilsandcrops.ca]}

Understanding the Basics of Cold tolerance and its Basis in Agronomic Decisions for Winter Cereals on the Canadian Prairies

Author(s): R. James Larsen

Summary: Cold tolerance is the most basic requirement for winter cereals on the prairies and considerable research efforts have been made throughout western Canada to improve cultivars and the production system. Upstream of this research is the underlying mechanism of cold tolerance including: how cell membranes deal with cold and freezing temperatures, the plants’ genetic response to cold temperatures, and the adaptation of photosynthesis to low temperatures. Early, shallow planting of winter cereals optimizes the plant’s ability to maintain photosynthesis and produce the building blocks for plant establishment and acclimation, ensuring the maximum cold tolerance potential of the cultivar is reached.

_{Citation: Larsen, R.J. Understanding the Basics of Cold tolerance and its Basis in Agronomic Decisions for Winter Cereals on the Canadian Prairies. 2013. Prairie Soils and Crops 6:87-98. [http://www.prairiesoilsandcrops.ca]}

Establishing a Symbiotic Relationship Between Legume Plants and Rhizobial Bacteria

Author(s): Fran Walley

Summary: Legume crops commonly grown in western Canada have the ability to form an association with a bacterial partner, called Rhizobium, and together these partners are capable of “fixing” gaseous nitrogen into a form that is plant available. This symbiotic association is beneficial to both partners. The plant is able to access a form of nitrogen that otherwise is unavailable, and the bacteria receive a ready source of energy from the plant. This remarkable partnership between plant and bacteria is highly organized and coordinated. Indeed, the simplicity of using a commercial rhizobial inoculant to enhance nodulation and ensure adequate nitrogen fixation in commercial legume crop production belies the complexity of the partnership. An examination of the many steps leading to the establishment of a symbiotic Nfixing association helps reveal factors that can contribute to, or prevent, successful nodulation.

_{Citation: Walley, F. Establishing a Symbiotic Relationship Between Legume Plants and Rhizobial Bacteria. 2013. Prairie Soils and Crops 6:99-106. [http://www.prairiesoilsandcrops.ca]}

General Principles of Plant Water Relations

Author(s): R. A. Bueckert

Summary: The term “water relations” describes plant water status at a cell, individual organ (leaf, internode, flower) or whole plant level, furthering our understanding of basic plant growth and development, and plant response to the environment. At the field level, water use and water use efficiency are the common means of evaluating a crop and its yield performance to seasonal water availability. Water use and water use efficiency measure overall crop water use in a field over a season whereas water relations measures plant water status at a point in time. Water relations is a subject that spans plant physiology, crop science, agronomy and irrigation management through the common concept of water potential – thus allowing measurement and detailed description of plant response to water availability within part of the cropping season or field. The subject of plant water relations is large; this article will be restricted to major principles associated with plant water status and several key measures of stress physiology.

_{Citation: Bueckert, R.A. General Principles of Plant Water Relations. 2013. Prairie Soils and Crops 6:107-118. [http://www.prairiesoilsandcrops.ca]}