A review of indicators of healthy agricultural soils with pea footrot disease suppression potentials

The quality of a soil is often viewed in relation to its ability to suppress plant disease and enhance agricultural productivity. A soil is considered suppressive when, in spite of favourable conditions for disease incidence and development, a pathogen cannot become established, or establishes but produces no disease, or establishes and produces disease for a short time and then declines. The interplay of biotic and abiotic factors has long been known to assert disease suppressive capabilities or otherwise. However, the multi-functionality of soil makes the identification of a single property as a general indicator of soil health an uphill task. In this paper, therefore, some indicators of soil health important to agriculture are reviewed with emphasis on pea footrot disease suppression potentials. Findings show that footrot disease due to Nectria haematococca (anamorph Fusarium solani f.sp pisi) is a globally, economically important disease of peas, and an initial inoculum density of ? 100 pathogenic forms of N. haematococca cells would produce an appreciable level of pea footrot disease depending on the relative amount of phosphorus, carbon and nitrogen present in soil. It would be desirable to confirm pea footrot disease models obtained from pot experiments with results from field experiments.