Agriculture Reference
In-Depth Information
Good farming practices are essential for long-term agricultural sustainability. Farmers
now include management practices such as reduced tillage, crop rotation, and overwin-
tering cover crops with the goals of reducing soil erosion, managing nutrient availabil-
ity, building soil organic matter, controlling weeds, and maintaining yields. What was
not considered when these practices were developed was the role of soil biology in the
success of these practices or the effect of these practices on soil biology. An important
component of the soil biological community is AM fungi. AM fungi form a mutualistic
symbiosis with the majority of crop plants. Among the benefits to the plant ascribed
to the symbiosis are enhanced nutrient uptake, water relations, and disease resistance.
Studies of the biology and function of these organisms help to answer the question of
how AM fungi are impacted by, and what their roles are in the success of, these farm-
ing practices.
Reduced tillage is increasingly practiced to enhance soil quality through reducing soil
erosion and building levels of soil organic matter. It also enhances the dual functioning of
the extraradical phase of AM fungi as both the nutrient-absorbing organ of the symbiosis
and an important source of inoculum for the new crop. Crop rotations not only combat
yield decline in continuous monocultures but also help guard against the characteristic of
AM fungi that those that proliferate on a given host plant species are not necessarily those
that enhance its growth. Overwintering cover crops are planted to retain or replenish soil
N, retard soil erosion, and compete with weeds. An added benefit is that they can act as
host plants for AM fungi and in so doing boost their populations. The cover crop provides
host roots to colonize and from which to procure fixed carbon during what would other-
wise be a bare fallow period for these obligate symbionts. Therefore, understanding the
soil biological underpinnings of farming practices can aide in their success and should be
considered in developing the sustainable agricultural practices of the future.
References
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