For further information contact: Peter Okoth

The soil biota constitute a significant proportion of global terrestrial biodiversity, and are responsible for critical ecosystem functions such as the biological control of soil-borne pests and diseases; decomposition; nutrient acquisition, storage and cycling; soil organic matter synthesis and mineralization; soil structural modification; and regulation of atmospheric composition. Research on the biological processes of soil lags behind those related to physical and chemical management such that these functions remain largely underexploited by humans for products and services in agriculture.

Recent advances in the understanding of soil ecology and in molecular methods for the study of soil offer promising ways to reverse the historical neglect of below-ground dynamics. New methods using gene micro-arrays, DNA profiling, DNA and RNA sequencing, and fatty acid analysis represent powerful approaches to understand the relationship between soil microbial communities and biogeochemical processes, equivalent to the genomic revolution in crop improvement. A programme of strategic research is required to realise this potential. A specific approach likely to yield high impact in the short to medium term is via the exploitation of the interactions between pest and disease management and soil fertility, involving the following lines of research:

• Develop cultural and bio-control practices to manage the interactions of soil fertility with plant vigour, and the reduction of plant pest inoculum;
  
• Develop quantitative techniques for monitoring and manipulating key functional groups of soil biota and their relationship to ecosystem service functions and plant health;
  
• Develop and validate management practices for key groups of beneficial soil organisms for small-scale farms; and
  
• Link local knowledge about biological indicators of soil quality with scientific knowledge to develop robust soil quality monitoring systems that combine precision and relevance.
  

Below-Ground Biodiversity

TSBF-CIAT will also continue research on below-ground biodiversity (BGBD) as a means of beneficially managing soil biology, through the GEF-UNEP funded global project on BGBD. The project addresses how BGBD can be managed and conserved in tropical agricultural landscapes. The processes of land conversion and agricultural intensification are a significant cause of biodiversity loss, including that of BGBD, with consequent negative effects both on the environment and the sustainability of agricultural production.

The objective of the GEF-UNEP project is "to enhance awareness, knowledge and understanding of BGBD important to sustainable agricultural production in tropical landscapes by the demonstration of methods for conservation and sustainable management." The project has a particular focus on tropical forest margins and the complex community of organisms which regulates soil fertility, greenhouse gas emissions and soil carbon sequestration, and which is routinely ignored in biodiversity conservation and assessment projects. The project will explore the hypothesis that, "by appropriate management of above- and below-ground biota, optimal conservation of biodiversity for national and global benefits can be achieved in mosaics of land uses at differing intensities of management and furthermore result in simultaneous gains in sustainable agricultural production." Integrated management of soil pests, diseases and nematodes will be of particular importance in ISFM practices. BGBD research also complements the work on breeding of cereals and legumes for tolerance to soil stresses, particularly drought and low soil fertility.