Abstract. Tillage is a central element in agricultural soil management and has direct
and indirect effects on processes in the biosphere. Effects of agricultural
soil management can be assessed by soil, crop, and ecosystem models, but
global assessments are hampered by lack of information on the type of tillage
and their spatial distribution. This study describes the generation of a
classification of tillage practices and presents the spatially explicit
mapping of these crop-specific tillage systems for around the year 2005. Tillage practices differ by the kind of equipment used, soil surface and
depth affected, timing, and their purpose within the cropping systems. We
classified the broad variety of globally relevant tillage practices into six
categories: no-tillage in the context of Conservation Agriculture,
traditional annual, traditional rotational, rotational, reduced, and
conventional annual tillage. The identified tillage systems were allocated to
gridded crop-specific cropland areas with a resolution of 5 arcmin.
Allocation rules were based on literature findings and combine area
information on crop type, water management regime, field size, water erosion,
income, and aridity. We scaled reported national Conservation Agriculture
areas down to grid cells via a probability-based approach for 54 countries.
We provide area estimates of the six tillage systems aggregated to global and
country scale. We found that 8.67 Mkm2 of global cropland area was tilled
intensively at least once a year, whereas the remaining 2.65 Mkm2 was
tilled less intensely. Further, we identified 4.67 Mkm2 of cropland as an
area where Conservation Agriculture could be expanded to under current
conditions. The tillage classification enables the parameterization of different soil
management practices in various kinds of model simulations. The crop-specific
tillage dataset indicates the spatial distribution of soil management
practices, which is a prerequisite to assess erosion, carbon sequestration
potential, as well as water, and nutrient dynamics of cropland soils. The
dynamic definition of the allocation rules and accounting for national
statistics, such as the share of Conservation Agriculture per country, also
allow for derivation of datasets for historical and future global soil
management scenarios. The resulting tillage system dataset and source code
are accessible via an open-data repository (DOIs: https://doi.org/10.5880/PIK.2019.009
and https://doi.org/10.5880/PIK.2019.010, Porwollik et al., 2019a,
b).
Associations Between Different Soil Management Practices, Soil Fauna and Maize Yield