Final answer:
Soil structure significantly influences the level of macroporosity in soil because it determines the size and distribution of the soil's pores, affecting oxygenation and water availability for plants.
Step-by-step explanation:
True, soil structure indeed affects the amount of macroporosity. The structural arrangement of soil particles determines the size and distribution of pores within the soil which, in turn, influences water and air movement, and biological activity. Biological factors such as the presence of microorganisms, plant roots, and the decomposition of organic material contribute to the development of soil structure. For instance, earthworms can create larger pores within the soil through their burrowing activities. Moreover, the solid/water/air ratio is vital for providing the necessary oxygenation levels and water availability for plant roots. If the soil has too much porosity, it may not retain sufficient water for plants, especially during dry conditions. Conversely, if the soil does not drain well, it can become waterlogged, leading to anoxic conditions that can harm plant roots.