A farmer grows wheat in the same field every year. The farmer does not add any fertiliser.
The yield of wheat decreases each year.
Explain why the yield of wheat decreases each year.
The farmer decides to add a fertiliser that contains nitrates.
Explain why wheat plants need nitrates for growth.
Another farmer uses crop rotation. She grows clover in the field one year and wheat in the field the next year.
Clover plants have root nodules.
Explain how growing clover increases the amount of nitrate in the soil.
44 exam-style questions on Edexcel GCSE Biology 9.3 Material cycles and decomposition, covering 9.3.1 Cycling of materials through ecosystems, 9.3.2 The carbon cycle, 9.3.3 The water cycle, 9.3.4 The nitrogen cycle, 9.3.5 Indicator species and pollution, 9.3.6 Decomposition in preservation and composting, and 9.3.7 Rate changes in decay of biological material. Each one has a worked solution and a mark scheme showing where the marks go.