Finding More Sustainable Ways To Cultivate Rice Crops

By Matt Olson

Rice farmers depend on phosphorous fertilizers to maximize their yields of this major staple food, which helps nourish more than half of the world's population. However, there is a finite supply of the nutrient available to be mined.

Dr. Joerg Schaller and colleagues discovered that silicon, which is also known to play a key role in growing rice, can replace phosphorus in soil and mobilize it to be available for absorption by the plants that need it. Phosphorus binds to iron in soil, rendering it unavailable to plants.

"If all the building places are occupied with silicon, there is no space for phosphate to bind (in the soil). It means you need only half of the fertilizer," said Schaller, who is with the Leibniz Centre for Agricultural Landscape Research (ZALF).

By taking multiple soil samples from rice paddies that have been used to cultivate rice for between 50 and 2,000 years and examining them using scanning transmission X-ray microscopy at the CLS, Schaller and his colleagues were able to better understand how and why silicon and phosphorus bond to the soil.

The wide range of paddy soil gave Schaller's team a precise look at how long it takes soil to be depleted of silicon and saturated with phosphorus.