IELTS Listening Part 4 Gapfill practice (soil and CO2)

Rattan Lal:

• Erosion is more likely in soil that is 31 dry

Carbon-rich soil is dark, crumbly and fertile, and retains some water. But erosion can occur if soil is dry, which is a likely effect if it contains inadequate amounts of carbon.

• Lal found soil in Africa that was very 32 hard

Lal was studying soils in Africa so devoid of organic matter that the ground had become extremely hard.

• It was suggested that carbon from soil was entering the atmosphere

Soil and carbon:

• Plants turn CO2 from the air into carbon-based substances such as 33 sugars

Plants absorb CO2 from the air and transform it into sugars and other carbon-based substances.

• Some CO2 moves from the 34 roots of plants to microbes in the soil

While a proportion of these carbon products remain in the plant, some transfer from the roots to fungi and soil microbes, which store the carbon in the soil.

• Carbon was lost from the soil when agriculture was invented

Regenerative agriculture:

• Uses established practices to make sure soil remains fertile and  35 moist

Some growers have already started using an approach known as regenerative agriculture. This aims to boost the fertility of soil and keep it moist through established practices.

• E.g. through year-round planting and increasing the 36 variety of  plants that are grown

These include keeping fields planted all year round, and increasing the variety of plants being grown.

California study:

• Taking place on a big 37 cattle farm

Soil scientist Wendy Silver of the University of California is conducting a first-of-its-kind study on a large cattle farm in the state.

• Uses compost made from waste from agriculture and 38 gardens

She and her students are testing the effects on carbon storage of the compost that is created from waste – both agricultural, including manure and cornstalks, and waste produced in gardens such as leaves branches and lawn trimmings.

Australia study:

• Aims to increase soil carbon by using 39 grasses that are always green

In Australia, soil ecologist Christine Jones is testing another promising soil-enrichment strategy. Jones and 12 farmers are working to build up soil carbon by cultivating grasses that stay green all year round.

Future developments may include:

• Reducing the amount of fertilizer used in farming
• Giving farmers 40 payment for carbon storage, as well as their produce.

Rattan Lal argues that farmers should receive payment not just for the corn or beef they produce, but also for the carbon they can store in their soil.