Soil Chemical Properties
Knowing our soil chemical properties
Last year we progressively discussed the components of the first step of the SIX EASY STEPS process. As we explained, this first step “Knowing our soils” relates to an understanding of the soil properties that affect nutrient management. In successive past issues, we dealt with some of the basic soil properties that included soil colour, soil texture, soil structure, effective soil depth, and position of soils in the landscape. In addition to these basic properties, soil chemical properties play a very important role in determining nutrient availability and the way we manage nutrients within a cropping system. In this issue we complete the description of the first of the SIX EASY STEPS by describing some of these important soil chemical properties.What determines soil chemical properties?
Soil chemical properties are largely determined by clay and soil organic matter particles. The existence and characteristics of both of these types of particles have been described in previous issues. Their influence on soil chemical properties is due to their reactivity (often associated with their electrostatic charge) and their overall large surface areas (due to their small particle size).
How are chemical properties determined?
Soil chemical properties are determined by analysing soil samples in a laboratory. These analyses are done using specific methods and procedures.
What soil chemical properties are considered important for sustainable nutrient management in the sugarcane production system?
Fundamental soil chemical properties (Table 1) that are considered important for sustainable nutrient management in sugarcane production are cation exchange capacity (CEC), soil pH and soil acidity, organic matter content, phosphorus sorption capacity, soil sodicity, and soil salinity. Each of these properties is described in Table 1. In addition to these determinations, soil samples are also analysed to estimate the amounts of nutrients available for plant uptake.
Having considered a comprehensive range of soil properties that affect nutrients and nutrient management, the first of the SIX EASY STEPS “Knowing our soils” is complete. The ‘scene is now set’ for moving to the second of the SIX EASY STEPS “Understanding and managing nutrient processes and losses”.
In the next issue of the Australian Canegrower we will begin discussing this next step
For further information contact:
Dr Bernard Schroeder, BSES Limited, Bundaberg - 4155 7400.
Dr Tim Wrigley, canegrowers, Brisbane - 3864 6444.
