Changes in distribution patterns of soil penetration resistance within a silage-corn field following the use of heavy harvesting equipments

摘要

Soil compaction caused by heavy wheeling reduces water infiltration, root development, and yield, and increases bulk density and soil strength. The objective of this study was to determine changes in spatial variability patterns of soil penetration resistance before and after using the silage machine in a corn-growing field. Soil penetration resistance was measured in a 100 × 400 m field with 10 m intervals just before and after harvesting. Measurements were taken from the 20 cm top layer on rows and inter-rows throughout each transect. The mean penetration resistance of 1353 measurements before and after harvesting was 2097 and 3116 kPa, respectively. Average bulk density within the field increased from 1.14 g cm-3 to 1.46 g cm-3, but wet aggregate stability decreased from 33.4% to 17.9% following harvesting. Punctual kriging analysis was performed to prepare distribution maps of soil penetration resistance with 1 m intervals within the field. The patterns of variation in soil penetration resistance following harvesting showed remarkable differences compared to pre-harvesting. Key words: Aggregate stability, bulk density, kriging, penetration resistance, soil compaction, spatial variability