ABSTRACT
The interactive relationships between the growth and functional characteristics of root systems, on the one hand, and the conditions in their surrounding rhizospheres, on the other, are certainly complex. Even under optimal conditions for root growth, the percentage of soil volume exploited will decline according to the solubility of the respective elements. Recognizing how little soil is rhizospheric relative to the total volume of soil is of practical relevance for determining the best fertilization practices for field-grown plants. A more sustainable and more widely used technique is to place the fertilizer that is considered necessary near the restricted root system. Deep placement of fertilizer patches can help improve nitrogen (N) uptake in dry soils because roots will generally grow deeper to overcome plant growth inhibition and limited nutrient acquisition. Agricultural management practices such as conventional tillage, inputs of mineral fertilizers and fungicides, limited crop rotation, and cultivation of nonmycorrhizal crops will negatively affect the establishment of mycorrhizal associations.
