Plant root development as a measure of soil health

Healthy soil is of primary importance for sustainable vegetable production. Soil biology drives many of the soil processes that are critical to crop productivity, including deleterious effects associated with pests and diseases. While soil health is a much-studied field, most research has focused on soil biota and soil physical factors with little attention on the interaction between crops and the soil biology. Plant roots are the first sites of interaction between the plant system and soil biology, and their position at this interface potentially provides a direct measure of soil health. We investigate the root system development in Capsicum (Capsicum annuum L.), a model plant due to its vulnerability to soil born pathogens, under management practices that aim to improve the soil health. Field trials involving the addition of different organic matter amendments revealed higher microbial activity than unamended controls, yet organic matter additions resulted in less 'vigorous' root systems. Treatments that induced longer root systems produced higher crop biomass and yield. Data from pot trials examining soil C:N ratios suggest that microbial mediated nutrient dynamics partially explain this response and have also shown that the pattern of root development can provide insight into the interactions between microorganisms, soil nutrient supply and plant development. Root system analysis can contribute to a better understanding of plant-microbe-soil interactions, aiding in the development of practices to better manage soil health and improve sustainability of horticultural production systems.