Joint International Conference on Long-term Experiments ...

GREENHOUSE GAS EMISSION IN LONG-TERM TILLAGE AND
ROTATION EXPERIMENTS
1 Anita Gál, 1 Péter Hegymegi, 1 Erika Michéli, 2 Tony J. Vyn
1 Szent István University, Soil Science and Agrochemistry Department, Gödöllő, HU
2 Purdue University, Department of Agronomy, West Lafayette, Indiana, USA
ABSTRACT
Greenhouse gases such as carbon-dioxide (CO2), and nitrous oxide (N2O) are strongly
linked to global warming. Soil organic matter is influenced by tillage and rotation, and
through its decomposition and accumulation, soils have a major effect on the gas
composition of the atmosphere. Tillage systems vary substantially in the intensity and
depth of soil disturbance, in crop residue placement, and in the resulting depths of soil
carbon gains or losses. The actual effect of different tillage practices on soil carbon
storage is highly dependent on the crops produced in the field. Several studies have
been conducted to determine the quantity and distribution of organic carbon and total
nitrogen under different tillage and rotation systems in long-term studies but less is
known about the relationship of OC and N stored in the soil and the emission of CO2,
and N2O from the soil over the crop production cycle. In our research we have
compared the long-term effects of conservation (no-till) and conventional (chisel plow
and moldboard plow) tillage systems on soil CO2, and N2O emission, in continuous corn
and soybean-corn rotation. Our results show that both tillage and rotation systems
influence significantly gas emission. Carbon-dioxide and nitrous-oxide emission
declines in the growing season with time. Nitrous-oxide emission increases after
application of nitrogen fertilizer and after heavy rain events. Corn monoculture gives
the highest emission of carbon-dioxide, and also for nitrous-oxide, rotations including
corn or corn monoculture have the highest emission. As for tillage treatments, chisel
plowing results in the highest emission of nitrous-oxide.
Keywords: organic matter, carbon sequestration, no-tillage, gas emission, rotation
INTRODUCTION
Greenhouse gases such as carbon-dioxide (CO2), and nitrous oxide (N2O) are strongly
linked to global warming because of their effects on radiation (Sparks, 2003). Organic
matter is a major soil component which is influenced by tillage and rotation, and
through its decomposition and accumulation, soils have a major effect on the gas
composition of the atmosphere (Eswaran et al., 1993, Kimble et al., 1990).
Tillage systems vary substantially in the intensity and depth of soil disturbance, in
crop residue placement, and in the resulting depths of soil carbon gains or losses. In notill,
which is the ultimate conservation tillage system, soil disturbance is limited to the
opening of a small slot for seed and fertilizer placement. In contrast, moldboard plowing
inverts the soil and most surface residue to a depth between 20-25 cm (Phillips et al.,
1980). Chisel plowing loosens soil to similar depths but does not invert the soil profile,
so it distributes residues more evenly and at shallower depths than moldboard plow.
After several years, soils which have undergone no-till have a higher carbon
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