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Extension Education: Sainfoin Response to Phosphorus

by Wyoming Livestock Roundup

Sainfoin is an introduced perennial forage legume that can be a good alternative to alfalfa. 

Sainfoin is highly palatable and nutritious and is preferred over alfalfa by cattle, sheep and some wildlife, including deer. Sainfoin does not cause bloat problems in cattle, has limited insect pests, such as resistance to alfalfa stem nematode, is non-invasive, has excellent drought tolerance and cold hardiness and is an excellent candidate for honey production. 

There are a few varieties available to purchase, including “Shoshone,” “Delaney,” “Eski,” “Remont” and “Rocky Mountain.” 

In a trial at the Powell Research and Extension Center (PREC), these sainfoin varieties produced about one ton of dry matter (DM) per acre from one harvest in 2007, its establishment year, which was about 0.5 ton lower than “Ranger” alfalfa. 

However, in the following years, all varieties produced similar or even higher DM yields than alfalfa from two cuts ranging from five to seven tons per acre. Shoshone yielded the most, with up to seven tons per acre. 

Forage quality of sainfoin was also similar to alfalfa. For sainfoin, crude protein is at 17 to 19 percent, total digestible nutrients are at 61 to 65 percnet and a relative feed value of 130 to 144. Sainfoin likes calcareous soils, or those soils with high calcium and pH, and also soils with low phosphorus. However, anecdotal evidence suggests that sainfoin may respond to phosphorus fertilization.

It seems to me that people are interested in sainfoin. Recently, I received many calls about sainfoin and enquiries about its response to phosphorus. 

Recent studies at PREC found no differences among the phosphorus treatments for forage yield in 2007planted sainfoin. However, numerically the highest yield was obtained in 2009planted sainfoin with phosphorus treatment of 60 pounds P205, which yielded five to six  tons per acre from two harvests. 

Likewise, no differences were observed in forage quality among different phosphorus treatments indicating that phosphorus does not alter or change forage quality. 

It was thought that old sainfoin stands and surface application of phosphorus may have contributed to this nonsignificant result. In 2011, a new stand of sainfoin was established at PREC and phosphorus treatments were incorporated into the established plots in 2012. When phosphorus was incorporated into soils, data revealed that yield was increased by 64 percent over the control, which had no phosphorus application, with the addition of 20 pounds P2O5, while further addition of P2O5 up to 60 pounds had minimal effect on yield increase. Interestingly, the highest rate – 80 pounds P2O5 – increased yield only by 12 percent over the control. 

The study is being repeated in 2013 to see the effects of phosphorus in the second year after establishment. I will update the results again when the data will be available.

Anowar Islam is an assistant professor and the University of Wyoming Extension Forage Agroecologist in the Department of Plant Sciences in the College of Agriculture and Natural Resources. He can be reached at 307-766-4151 or

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