Soil Quality and Plant Nutrition

Abstract

Soils are dynamic ecosystems that support a diversity of life. Therefore, the concept of soil quality or health, like that of human health, is not difficult to understand or recognize when the system is viewed as a whole. The challenge is to manage soils such that they are able to perform the various uses they are put to without degradation of the soils themselves or the environment. While, this is simple in concept, there are definite complexities that make the idea of soil health difficult to quantify. Which soil functions should be considered, which soil properties are most important to measure, and how to best measure those properties are some of the tough questions that need to be considered when attempting to quantify soil health. The great challenge is to manage soils in a sustainable fashion so that they will provide for human needs in the future. However, the measurement of soil processes and of the soil properties linked to these also depend on the use and location of the soil. When evaluating soil quality, it is therefore common to explore a range of soil physical, chemical, and biological properties. The single most important property determining the soil quality is the soil organic system because of the profound influence it has on soil physical, chemical, and biological properties. Therefore, many steps already taken to improve soil quality are dealing with improving soil organic matter status and hence, the vitality of the soil organic system. Some of the common ways to improve soil quality include: reduced tillage, use of green manure, application of animal manures, crop rotations, strip cropping, use of cover crops, application of sludge or biosolids, and other additions of organic materials and nutrients. These management techniques enhance the activity of both the micro- and macro-biological soil organic system, whose activities also improve properties such as soil aggregation, infiltration, and water holding capacity, decrease bulk density, penetration resistance and soil erosion, and increase cation exchange capacity. Management for soil quality can also lead to reduced need for agrochemicals and tillage, reduced fuel consumption by farm equipment, and increased sequestration of CO2 in the soil, all of which benefit the environment. Modern agricultural science has the ability to correct many of the poor practices of the past and to maintain healthier soils that should sustain the uses they are put to.