Agriculture Reference
In-Depth Information
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Micro-herbivores
Macro-herbivores
Low
High
Intensity of Herbivory
Figure 10.3
Low levels of micro-root herbivores such as nematodes and other small organisms can
result in compensatory growth or overcompensation by the plant in contrast to that caused by mac-
roherbivores. Larger soil invertebrates feeding on roots can cause significant damage or death of
roots. (Modified from Seastedt, T., and P. Murray. 2008. Root herbivory in grassland ecosystems.
In
Root Feeders: An Ecosystem Perspective
, ed. S. Johnson and P. Murray, 54-67. CAB International,
Wallingford, UK. With permission.)
exotic biocontrol organisms (Kerry and Hominick, 2002; van der Putten et al., 2006; Gao
et al., 2008). And, there can be positive benefits. van der Putten et al. (2006) noted that in
wild systems, root parasitic nematodes, other root feeders, and pathogens drive commu-
nity processes such as plant species diversity and succession because they have coevolved
with the plants and their enemies. These examples illustrate that knowledge of the biology
of the pathogen and plant host and pests and predators from wild land and agricultural
systems can be successfully transferred into some managed agriculture strategies (van der
Putten et al., 2006; Crute and Muir, 2011; Pritchard, 2011).
Managing soil biodiversity for small-scale agriculture and promotion of ecosys-
tem services was the focus of a United Nations Environment Program (UNEP)-Global
Environmental Fund project in several tropical countries. The Conservation and Sustainable
Management of Below-ground Biodiversity (BDBD) Project of the Tropical Soil Biology and
Fertility (TSBF) Institute of the International Center for Tropical Agriculture (CIAT) based
in Nairobi, Kenya, spent more than a decade working with expert scientists from seven
countries to develop international standards for the inventory of belowground biota under
a range of land uses in the humid tropics. Although the early work was on the use of organic
matter and how carbon and nitrogen are supplied to plants, the result of the program was a
focus on the organisms that mediate the processes, functions, and services of soil.
The
Handbook of Tropical Soil Biology
(Moreira et al., 2008) is a primary example of rec-
ognition by experts who work in the poorest regions of the world's most rapidly deforested
areas that management of soil biodiversity can be employed to enhance soil ecosystem
services such as soil fertility and biological control of soil pathogens in agroecosystem
management. Methods in the topic were tested in the seven participating tropical coun-
tries on three continents by local experts, biologists, and managers who had varying lev-
els of expertise in identification. The program included building capacity of the scientists
in aspects of soil biology, soil fertility, crops, and ecosystem services and experiments
that could be compared on measures to manipulate soil biodiversity to increase biologi-
cal control and plant health. The framework that was developed for manipulating soil
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