A farmer in Brazil noticed that soil fertility decreased after several years of continuous crop cultivation. Which of the following practices would most effectively restore nitrogen levels in the soil?

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Question

A farmer in Brazil noticed that soil fertility decreased after several years of continuous crop cultivation. Which of the following practices would most effectively restore nitrogen levels in the soil?

Accepted Answer

Planting leguminous crops such as beans or clover — Award 1 mark for recognising that leguminous crops contain nitrogen-fixing bacteria in root nodules that convert atmospheric nitrogen into nitrates. A is incorrect — irrigation does not add nitrogen; it may actually leach nitrates away. C is incorrect — carbon dioxide does not restore nitrogen levels. D is incorrect — decomposers are essential for releasing nitrogen from organic matter.

Answer

Removing all decomposers from the soil

Answer

Adding more carbon dioxide to increase photosynthesis

Answer

Increasing irrigation to wash more nitrogen into the soil

Answer

Planting leguminous crops such as beans or clover

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