May 28, 2016

In general, most plants grow by absorbing nutrients from the soil. Their ability to do this depends on the nature of the soil. Depending on its location, a soil contains some combination of sand, silt, clay, and organic matter. The makeup of a soil (soil texture) and its acidity (pH) determine the extent to which nutrients from feritilizers are available to plants.


Soil Texture (the amount of sand, silt, clay, and organic matter in the soil) 
Soil texture affects how well nutrients and water are retained in the soil. Clays and organic soils hold nutrients and water much better than sandy soils. As water drains from sandy soils, it often carries nutrients along with it. This condition is called leaching. When nutrients leach into the soil, they are not available for plants to use.
An ideal soil contains equivalent portions of sand, silt, clay, and organic matter. Sometimes, the nutrients that plants need occur naturally in the soil. Othertimes, they must be added to the soil as lime or fertilizer.

Soil pH (a measure of the acidity or alkalinity of the soil)  

Soil pH is one of the most important soil properties that affects the availability of nutrients. 
Macronutrient fertilizers tend to be less available in soils with low pH.
Micronutrient fertilizers tend to be less available in soils with high pH.
Lime can be added to the soil to make it less sour (acid) and also supplies calcium and magnesium for plants to use. Lime also raises the pH to the desired range of 6.0 to 6.5.
In this pH range, nutrients from feritilizers are more readily available to plants, and microbial populations in the soil increase. Microbes convert nitrogen and sulfur to forms that plants can use. Lime also enhances the physical properties of the soil that promote water and air movement.