Below are links and other resources that explain more about Big Trefoil.  If you'd like to recommend a link, click here.

General Resources about big trefoil:

Links:
Oregon Big Trefoil Fact Sheet.  An excellent general resource.
Big Trefoil article from Purdue  Another excellent resource.
Scientific article on Big Trefoil from New Zealand   A bit technical, but good.
Hawaiian article on Big Trefoil  Good general information, but seed sources may not be accurate :-)
Another Australian article   Good general information. Mostly applicable to 'Grassland Maku' big trefoil.

Books:
Frame, Chalton, Laidlaw. 1998 "Birdsfoot Trefoil & Greater Lotus" in Temperate and Forage Legumes.  CAB Press.  ISBN: 0-85199-214-5.
   This book is the best all-around reference that I've found.

Hafenrichter, Schwendiman, Harris, MacLauchlan, & Miller, 1979. Grasses & Legumes for Soil Conservation in the Pacific Northwest and Great Basin States. Agricultural Handbook #339. SCS-USDA.
   A good general handbook comparing many legumes. Contains many of the rarer plants.

Henson, 1962.  The Trefoils: Adaptation & Culture.  Agriculture Handbook no. 223.  USDA.
   Older article, but full of good information.  Difficult to find, though.

Howell, 1948.  A Legume for Acid Soils:  Lotus uliginosus (L. major).  Agricultural Experiment Station Bulletin #456, Oregon State University.
   Almost impossible to find now, but one of the best articles detailing how Big Trefoil grows on acid soils.

Rhykerd, Johnson, & Hankins. 1981. "Big trefoil production and potential in Southern Indiana." Agronomy Guide AY-232. Purdue University Cooperative Extension Service.
   A discussion on big trefoil in Indiana and the foundation of the Kaiser cultivar.

Blumenthal & McGraw, "Lotus Adaptation, Use, and Management," 1999. in Trefoil:  The Science and Technology of Lotus.  CSSA Special Publications #28.  ASA-CSSA.
   A good overview of Lotus management.

Big Trefoil in Pastures/Forages:

Links:
OSU extension article on coastal pastures (*.pdf). The use of big trefoil in coastal pastures is elaborated well beginning on pg. 5.
Use of trefoil in Hawaiian soils.A large file to load. Big trefoil is discussed considerably in Hawaiian tropical soil management.
Australian article on pasture legumes. (*.pdf)Trefoil is on pg. 8.
Austrlian article on pasture plants for dairys (*.pdf) Lotus is on pg. 23

Specific aluminum, pH, and water tolerance of Big Trefoil:

Resources:
Edmeades, Blamey, Asher, & Edwards, 1991. "Effects of pH and Aluminum on the growth of temperate pasture species I & II." In Australian Agriculture Research 42:559-569 & 42:893-900.

Wheeler & Dodd, 1995.   "The effect of aluminum on the growth of a range of temperate legume species and cultivars: A summary of results." In Plant Soil Interactions at Low pH (R.A. Date et al. eds.) pp. 433-437.

   Two scientific articles with data showing aluminum tolerance of Lotus as compared to other legumes. Basically, big trefoil is unaffected by aluminum and does well in a low pH.

Shiferaw, Shelton, & So, 1992. "Tolerance of some subtropical pasture legumes to waterlogging." In Tropical Grasslands 26: 3,187-195.
   Documents how big trefoil survives well in waterlogged conditions.

Big Trefoil in Wildlife/Conservation/Forestry:

Links:
Forage comparisons for white-tailed deer habitat. Compares costs of different forages for deer. The 'grassland maku' cultivar of big trefoil is shown.
Research article on Lotus effect on butterflies. An interesting academic study, but inconclusive.
Honeybee & Pollination biology of Lotus  Book chapter that focuses primarily on pollination and honey production using Lotus.
Use of trefoil in Washington state for habitat.  Trefoil is listed in seed mixture recommendations on pg. 2. Note: also see Wash. State Dept. of Ecology Publication 657.
Woodland Fish & Wildlife (*.pdf). An Oregon publication with a general discussion on wildlife habitat. Big trefoil is listed in the seed mixture recommendations on pg 5.
Australian article on using Lotus in orchards  Using big trefoil as an understory plant in orchards. Interesting!

Articles:
West, Dean, & Perceval, 1991. "The productivity of Maku Lotus as a forest understorey." In Proceedings of the New Zealand Grassland Association 53:169-173.
     Discusses how big trefoil is used to seed forest understoreys for habitat and to prevent erosion.

Use of big trefoil in reclamation:

Resources:
Belesky, 1999.  "Lotus Species Used in Reclamation, Renovation, and Revegetation," 1999. in Trefoil:  The Science and Technology of Lotus.  CSSA Special Publications #28.  ASA-CSSA.
Great discussions on how Lotus is used for reclamation and soil improvement

Academic/Technical Resources:

Links:
The Lotus Newsletter   A research-oriented website/newsletter dealing with all aspects of the genus Lotus.

Books & Articles:
Trefoil:The Science and Technology of Lotus. CSSA Special Publications #28. ASA-CSSA.
   An academic publication on the entire genus. Good information.