Explain the factors that affect soil fertility

http://en.wikipedia.org/wiki/Fertile_soil

Soil fertility refers to the ability of soil to support the growth of plants and produce high crop yields. Several factors influence soil fertility, and understanding these factors is important for agricultural practices. Here are some of the main factors that affect soil fertility:

1. Organic matter content: Organic matter plays a crucial role in soil fertility by improving soil structure, moisture retention, nutrient availability, and biological activity. Adding organic materials such as compost, manure, and cover crops increases soil fertility.

2. Nutrient content: Essential plant nutrients, such as nitrogen, phosphorus, and potassium, significantly impact soil fertility. The availability of these nutrients can be affected by factors like soil pH, organic matter content, and microbial activity. Regular soil testing can help determine nutrient levels and guide fertilization practices.

3. Soil pH: Soil pH measures the acidity or alkalinity of the soil. Different plants have specific pH preferences, and soil pH affects nutrient availability. Most crops prefer a slightly acidic to neutral pH range (between 6 and 7), but this can vary depending on the plant species.

4. Soil texture: Soil texture refers to the relative proportions of sand, silt, and clay particles in the soil. Different soil textures have varying water-holding capacity, drainage characteristics, and nutrient-holding capabilities. Loam soils, consisting of a balanced mixture of sand, silt, and clay, are generally prized for their fertility.

5. Soil structure: Soil structure refers to how soil particles are arranged and aggregated. A well-structured soil allows for proper air circulation, water movement, and root penetration. Factors such as organic matter content, soil compaction, and tillage practices influence soil structure.

6. Climate and weathering: Climate affects soil fertility through temperature, precipitation, and weather patterns. Hot and dry climates lead to higher rates of evaporation and leaching, which can deplete nutrients. Additionally, long-term weathering processes break down rocks and minerals, releasing essential nutrients.

7. Microbial activity: Soil microbes, including bacteria, fungi, and other microorganisms, play a vital role in soil fertility. They help decompose organic matter, fix nitrogen, enhance nutrient availability, and suppress plant diseases. Maintaining a diverse and active microbial community is essential for soil health.

It's worth mentioning that these factors can interact and influence each other, ultimately influencing soil fertility. Understanding and managing these factors through soil testing, appropriate nutrient management, organic matter additions, and sustainable agricultural practices can help improve soil fertility and ensure long-term productivity.