Table of Contents
What is Soil Structure
Soil structure is the arrangement of soil particles, including sand, silt, and clay, and organic matter in the soil. It is the way in which soil particles aggregate and bind together to form distinct units called soil aggregates or peds. Soil structure affects the physical properties of the soil, including porosity, water retention, and aeration, which in turn affects the soil’s ability to support plant growth.
Soil structure can be classified into different types, depending on the size and shape of the soil aggregates. Some common types of soil structure include:
- Granular structure: Soil particles are arranged in large, round or angular aggregates, with large pores between them, which allows for good drainage and aeration.
- Blocky structure: Soil particles are arranged in large, roughly rectangular aggregates, with moderate pores between them, which allows for good drainage and moderate aeration.
- Platy structure: Soil particles are arranged in thin, flat aggregates, with small pores between them, which can lead to poor drainage and poor aeration.
- Columnar structure: Soil particles are arranged in long, vertical aggregates, with large pores between them, which allows for good drainage and aeration.
- Single-grained structure: Soil particles are not bound together, and there are no visible aggregates, leading to poor drainage and poor aeration.
A well-structured soil can support the growth of plants by providing enough water and oxygen, as well as a good environment for the microorganisms and roots to develop. Soil structure can be improved by adding organic matter such as compost, and reducing compaction through crop rotation or other methods.
What defines the structure of the soil
Soil structure refers to the arrangement of soil particles, including sand, silt, and clay, and organic matter in the soil. The following factors determine soil structure:
- Particle size: The size and distribution of soil particles, including sand, silt, and clay, determine the soil structure. Coarser soils, such as those with a high sand content, have a loose structure, while finer soils, such as those with a high clay content, have a dense structure.
- Organic matter: Organic matter in the soil improves soil structure by binding soil particles together, creating a more porous and aerated structure that is more conducive to plant growth.
- Microorganisms: Microorganisms in the soil, such as bacteria, fungi, and protozoa, play an important role in the formation of soil structure by breaking down organic matter and releasing nutrients and other beneficial compounds.
- Water content: Water plays a critical role in soil structure, as it helps to hold soil particles together and allows for the movement of air and water through the soil.
- Temperature: Temperature also affects the activity of microorganisms and the rate of organic matter decomposition, which in turn affects soil structure.
- Compaction: Human or animal activities, or heavy machinery that can compact the soil, reducing the pore spaces and making the soil more dense and harder for roots to penetrate.
- Topography and climate: The slope and position of the soil, as well as the climate, can affect the amount of water and air that reaches the soil and thus, affect the soil structure.
- Parent material: The parent material of the soil, such as rock, sand, clay, or volcanic ash can also influence the soil structure.
How compost improves the structure of soil
Compost can improve several aspects of soil, including:
- Soil structure: Compost adds organic matter to the soil, which improves the soil’s ability to retain water and nutrients, and also helps to improve the soil’s overall structure, making it easier for roots to penetrate.
- Drainage: The microorganisms in compost can help to break down clay soil particles and make them more porous, and also help to aerate heavy clay soil, which can improve its drainage.
- Nutrient content: Compost is rich in a variety of essential nutrients such as Nitrogen, Phosphorus and Potassium. Adding compost to soil can help to improve the nutrient content of the soil and make it more fertile.
- Biodiversity: The addition of compost to soil can increase the soil’s biodiversity, which can help to improve the overall health of the soil and the plants that are grown in it.
- Soil pH: Compost can help to neutralize acidic soils, making them more alkaline, which can benefit some plants that prefer slightly alkaline soils.
- Soil erosion control: Organic matter in compost helps to bind soil particles together, making the soil more resistant to erosion.
- Water retention: Compost can help to improve water retention in the soil, which can be beneficial for plants during dry periods.