Nutrient Absorption Basics for Soil and Plants

对表层土

Nearly all crops are grown in topsoil, the top layer of the earth. Topsoil is a micro-ecosystem that’s full of organic matter (decomposing plants and animals), 矿物质(氮, 磷, 等.), microscopic organisms (microbes, bacteria, fungi), anthropods (insects), worms, air, and water.

土壤类型

Though soils contain these same elements, they differ in soil texture. Soil texture refers to the amount of sand, 淤泥, or clay in the soil and varies greatly across North America. Soil texture is one of the most common features used by scientists and laymen to describe soils.
 

Understanding soil texture is important because certain soil textures are better suited for particular plants and crops. 一般来说, western soils contain more sand and loam, while eastern soils contain more clay and 淤泥. Because soil texture classes hold water and nutrients differently, it is an important factor to consider when deciding which plants to grow and which fertilizer will help the soil provide the plant with the best growing soil possible.
 

土壤pH值

In addition to varying soil textures, soils have varying levels of acidity called soil pH. 土壤pH值 is measured on a scale that starts at 1.0(酸性最强)变成7.0(中性)，结束于14.0(碱性最强). Every plant has a preferred pH level where it will thrive.

In general, most plants grow best at pH levels between 6 and 7 (neutral). Because soil pH levels outside that neutral range limit potential plant growth, growers will often add limestone to raise a soil pH or elemental sulfur to lower it. With the soil pH adjusted closer to the neutral range, plants have improved access to plant nutrients in the soil or provided through fertilizer.
 

土壤阳离子交换能力

土壤带一个负电荷, so it attracts and holds positively charged molecules called cations (iron, 钙, 镁). 带负电荷的分子, 哪些被称为阴离子(氮, 磷), 不被土壤吸引吗. This makes them more vulnerable to “leaching” from the soil and dissipating into the air, 植物无法获得的地方.
 

低CEC

Soil with a higher negative charge can hold more cations. By applying a product that affects the electromagnetic qualities of the soil, the cation exchange capacity (CEC) can be adjusted. This allows growers to “bind” or “fix” nutrients to the soil to reduce nutrient leaching.