Performance of Kura Clover (Trifolium ambiguum Bieb.) in Pure Stands and Mixtures with Perennial Grasses in Saskatchewan, Canada

论文摘要

Kura clover （Trifolium ambiguum Bieb.） is a long-lived rhizomatous perennial legume introduced from the Caucasian region of Russia. Kura clover is very winter hardy and drought tolerant although it will go through the dormant during the moisture stress. Kura clover is slow to establish. The poor establishment and seedling vigor has been contributed to substantial allocation of energy resources to the root system. Kura clover yield is usually lower than that of alfalfa, red clover or birdsfoot trefoil during the earlier years of production, but this trend reverses later because kura clover maintains its plant stand better than the above-mentioned legumes. The initial lower yield and subsequent longevity have been attributed to the development of an extensive rhizome system. Forage quality of kura clover is relatively high. However, it is suggested being used in mixtures with grasses due to the problem of bloat. Combing kura clover with grasses can dramatically reduce the concentration of NDF and ADF compared with grass monoculture thus improve the forage quality of the mixtures. In recent years, the livestock production is more and more important in agriculture. For the market requirement, farmers in Saskatchewan begin to pay attention to the forage cultivation. Kura clover, because of its persistent nature, cold and drought tolerance and high forage quality, may be an excellent species used in pastures of Saskatchewan. Some research work on kura clover-grass mixtures have been conducted in the United States, while there have been no kura clover studies conducted in the Province of Saskatchewan. Full-scale grassland ecology work with kura clover is new to Western Canada. To our knowledge this project may be the first study in the region with an ecological approach. The research objective is to evaluate the establishment, productivity and forage quality of two cultivars of kura clover in pure stands and mixtures with five perennial grasses, which are all the most important grasses used in Saskatchewan. This study was conducted in 2003 and 2004 at two Saskatchewan locations, University of Saskatchewan in Saskatoon and Outlook. The soil type is loam at Saskatoon and fine sandy loam （Typic Haploboroll） at Outlook. Kura clover was seeded in spring and the five cool season grasses were seeded: 1) at the same time （spring seeding） as kura clover and 2) in the late fall （dormant seeding） into established kura clover. Three of the most valuable parameters, NDF, ADF and CP content were measured to evaluate the forage quality and the yield production was also recorded. NDF and ADF were determined in an ANKOM fiber analyzer and CP was determined in a LECO nitrogen analyzer. In the kura clover pure stands, the NDF and ADF contents are rather low and the CP content is relatively high. It is clear that the forage quality of pure kura clover stands is perfect. In Saskatoon, NDF contents of the spring seeding plots for two cuts are 60.5% and 52.1%, separately, they are significantly higher （P<0.05） than those of dormant seeding plots （26.3% and 27.2% for two cuts, separately） because of more grasses and less kura. At the same time, in Outlook, NDF contents in the spring seeding plots of the two cuts are 58.7% and 50.9%, they are also significantly higher （P<0.05） than those of dormant seeding plots （25.7% and 37.3% for two cuts separately）. Thus we can get the conclusion that kura clover reduce the NDF content of clover-grass mixtures greatly and thus improve the forage quality. Similarly, the spring seeding plots also got significantly higher （P<0.05） ADF content than dormant seeding plots. In Saskatoon, ADF contents in spring seeding plots for two cuts are 34% and 29.9% while in the dormant seeding plots, ADF contents for two cuts are 20% and 20.2%, separately. In Outlook, ADF contents of spring seeding plots for two cuts are 32.4% and 29.9%, separately while those of dormant seeding plots for two cuts are 16.2% and 25%. In the same way we know that kura clover reduce the ADF content of the forage and consequently improve t

论文目录

• ABSTRACT
• INTRODUCTION
• 1.0 Forage
• 2.0 Forage Quality
• 3.0 Kura Clover （Trifolium ambiguum Bieb.）
• 3.1 Species Description
• 3.2 Distribution and Adaptation
• 3.3 Use
• 3.4 Cultivars
• 3.5 Cultivation and Management
• 4.0 Cool Season Grasses
• 4.1 Crested Wheatgrass （CWG）—（Agropyron cristatum）
• 4.2 Smooth Bromegrass （SBG）—（Bromus inermis）
• 4.3 Hybrid Bromegrass （HBG）
• 4.4 Meadow Bromegrass （MBG）—（Bromus riparius）
• RESEARCH BACKGROUND
• MATERIALS AND METHODS
• Seeding
• Plant Material
• Experimental Design and Treatments
• Sampling Procedures
• Statistical Analysis
• RESULT AND DISCUSSION
• ACKNOWLEDGEMENTS
• REFERENCES
• APPENDIX Ⅰ
• APPENDIX Ⅱ
• APPENDIX Ⅲ