Infiltration and Soil Properties as Affected by Annual Cropping in the Northern Great Plains
- Joseph L. Pikul and
- J. Kristian Aase
Fallow-wheat (Triticum aestivum L.) cropping systems may be responsible for declines in soil organic matter and degradation of soil physical properties. A change to annual cropping may improve or at least maintain soil properties. Tillage and crop sequence effects on soil properties and water infiltration were tested after 9 yr of cropping on a Dooley sandy loam (fine-loamy, mixed Typic Argiborolls) derived in glacial till. Annual cropping tillage of fall sweep and spring disk (AWFST), and no tillage (AWNT) were compared with conventional tillage in wheatfallow (FWCT) as the control. Statistical design was a randomized complete block with four replications. Soil samples were taken at 0.03−m increments to a depth of 0.3 m and were used to measure organic carbon (OC), pH, bulk density (BD), and particle size. Point resistance was measured in 0.02−m increments. Water infiltration into dry and wet soil was measured using a rainfall simulator. Maximum soil BD was 1.61 Mg m−3 on FWCT and 1.56 Mg m−3 on AWNT. Soil BD was not changed by one winter of freezing and thawing. Maximum point resistance was 2.2 MPa on FWCT and 1.7 MPa on AWNT. Cumulative 3-h infiltration into dry soil was 52 mm for FWCT and 69 mm for AWNT. Final infiltration rate into wet soil was 5 mm h−1 for FWCT and 6 mm h−1 for AWNT. There was a significant difference in the depth distribution of OC between annual crop and FWCT treatments. Mass of OC in the top 0.09 m of soil was 1.65 kg m−2 on annual crop treatments and 1.45 kg m−2 on FWCT. Greater amounts of OC on the annual crop treatments compared with the FWCT attest to the beneficial aspect of annual cropping in maintaining a level of soil quality that is greater than FWCT. From a soil conservation perspective, no-tillage has an additional advantage because surface cover is maintained throughout the year, thereby reducing the potential for soil erosion.
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