|Lipiec, J - INST AGROPHYSICS, POLAND|
Submitted to: Soil and Water Conservation Society Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 25, 1998
Publication Date: N/A
Technical Abstract: Reducing soil compaction by deep tillage is expensive in terms of both time and resources. If breeders can select genotypes with better root penetrability, tillage can be reduced. We developed a test to single out varieties with roots that can grow better in compacted soils. To check out the method, we compared two soybean genotypes for their tolerance to soil compaction. A loamy sand was compacted into 1-in (2.5-cm) deep, 3-in (7.5-cm) diameter cylindrical cores at bulk densities of 0.051, 0.056, 0.060, and 0.063 lbs/cu in (1.40, 1.55, 1.65, and 1.75 g/cc). Cores were built into columns that had about 2 in (5 cm) of loose soil on the top and cores of increasing bulk density with depth. Check columns were also included. In check columns, all cores were compacted at the lowest bulk density. Columns were not watered throughout the study. Two soybean varieties (one established - ES and one experimental - EX) were grown in the columns until they died. As expected, both varieties grew better and lived longer in soils with lower bulk density. Root growth was more abundant for ES than for EX. However, root growth of EX was not reduced in the compacted layers as much as it was for ES. EX was better able to penetrate compacted soil. This comparison was possible because we contrasted growth in columns with and without increasing bulk density. A single-compacted-layer test would not have been able to do this. Further use of the test can help screen other genotypes for their tolerance to soil compaction.