Spiritual Aspects of Sustainable Soil Management - Principles of Sustainable Soil Management in Agroecosystems - page 273

the welfare of the animals. Poor soil structure results from compaction by animal
hooves and wheel traffic, which restricts the growth of the pasture shoots and roots
due to low macroporosity, reduced biological diversity and activity, and restricted
nutrient uptake. One such affected soil (Figure 11.3) showed how the aeration status
and structural condition of the topsoil were reverting to those of the subsoil such
that the actual subsoil appeared to be in better structural condition than the topsoil.
Extra mineral nitrogen fertilizer is applied to compensate, and only part is used by
the grass, with the rest lost to the environment.
An important approach to improving the sustainability of these systems is to
maximize use of the soil biology. This is achieved by improved connection with
and response to soil conditions. Visual methods of crop and soil observation can
be used to adjust management to maintain high soil and pasture quality. Shepherd
(2009) attempts to improve the soil management by ensuring good soil structure and
aeration; choosing appropriate mixtures of grass, herbs, and clover in the pasture;
using simple pasture reseeding techniques; and using biologically friendly fertilizers
that promote carbon sequestration, nutrient turnover and cycling, and the release of
nitrogen slowly to the pasture. These combine to encourage earthworm and micro-
bial activity in the soil and allow good pasture production with low nitrogen fertil-
izer use. Healthy pasture results in healthy animals, and greenhouse gas emissions
are reduced relatively cheaply. Conservation shifts the emphasis from agribusiness
to husbandry when the farmer aims for a reasonable return rather than productivity.
A system of biological agriculture labeled by some as “beyond organic” is
Polyface farming, which was developed by the Salatin family (Salatin 2010). Their
FIGURE 11.3 Gleyed recent alluvial soil in North Island, New Zealand, poached suffi-
ciently by grazing for the topsoil structure and aeration conditions to start reverting to those
of the subsoil.