Field trials on low-selenium loess soils tested soil and foliar applications of selenium, zinc and iodine on wheat, maize, soybean, potato, canola and cabbage. Soil-applied selenate raised selenium in every crop, with cabbage responding most strongly, while soil-applied selenite was much less effective. Foliar selenite raised wheat grain selenium from 25 to 312 µg/kg.
Key numbers
- Wheat grain selenium: 25 µg/kg without foliar selenium and 312 µg/kg with foliar selenite at 60 g selenium per hectare (Abstract, p. 459).
- Soil selenate, increase per gram selenium per hectare: wheat 17.4, maize 8.6, soybean 17.3, potato 10.2, canola 4.1 and cabbage 76.8 µg/kg (Results, p. 463).
- Soil selenite, increase per gram per hectare: maize 0.2, soybean 1.2, potato 0.9 and cabbage 6.5 µg/kg (Results, p. 463).
- Target of 300 µg/kg dry weight reached with selenate at 16 (wheat), 34 (maize), 15 (soybean), 28 (potato), 71 (canola) and 3 (cabbage) g per hectare (Results, p. 463).
Methods (brief)
Crops were grown with local practice on three loess fields in Shaanxi. Selenium as selenate or selenite, zinc sulfate and potassium iodate were applied to soil, and selenite and zinc were sprayed on wheat at several rates. Edible parts were analyzed for selenium by ICP-MS after nitric acid and hydrogen peroxide digestion.
Evidence fitness
Supports crop-specific uptake differences and the much greater effect of selenate than selenite in soil. These are trial plots, not market foods.
Limitations
Concentration tables are image-only in the available copy, so only text-stated values were extracted. Support was acknowledged from HarvestPlus and the International Fertilizer Industry Association, among public funders. Detection limits are not stated.
Related evidence
Update history
No substantive edit history is available in this build. The full commit record is available in git.