Canola is a familiar sight in grassland agricultural areas but what is it doing in California? The centre of the state is intensively agricultural, boasting crops as diverse as nuts, olives, oranges, artichokes, grapes, and corn. But there are challenges to farming this land, and some US Department of Agriculture researchers are using canola to test its potential.

The problem is that, in many areas, the soil has higher than normal levels of inorganic selenium. With heavy reliance on irrigation, particularly in times of drought, water must be pumped from groundwater sources. This water has elevated selenium content due to contact with underlying layers of soil derived from marine sediments. Many plants cannot cope with the selenium level, and it can accumulate to dangerous amounts for wildlife.

Canola is a member of the mustard family and is grown primarily for cooking oil. Its high protein level makes it a high quality forage for livestock. Biodiesel can be produced from crushed canola seeds. But most relevant to California, canola is tolerant of selenium and can incorporate trace amounts into individual plants. This acts as a form of soil remediation by pulling out the problem element. Similarly, contaminated water benefits from the bioremediation effects of canola plants.

Kenaf, related to cotton, is also good at addressing high selenium levels. It is used as an alternative grain food. Among its various applications, kenaf can be processed to yield high-quality paperstock, acoustic tiles, bedding and litter for animals, and absorbent pads for industrial and agricultural use. Other crops, including some vegetables, and wild plants can also help absorb selenium, but canola offers additional advantages.

While high selenium levels are a problem, it is also a necessary micro-nutrient for people and many animals. In the US, at least 37 states experience selenium deficiencies - and supplementation is an essential part of raising livestock. Mineral injections and supplements are a regular part of ranching. So what could be better than finding a natural way to address both these challenges? By feeding canola grown on selenium-enriched soil, both the grower and the buyer can benefit.

In fact, along California’s Central Valley, the east side is selenium-deficient and the west side is selenium-contaminated - making it an ideal place to test canola’s effectiveness. Preliminary results are positive for both sheep and dairy cows. Even selenium that ends up in manure should not be an issue, as organic forms are more difficult for plants to use.

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