Soil Compaction Effects on Soybean Nodulation, N2(C2H4) Fixation and Seed Yield1
- W. C. Lindemann,
- G. E. Ham and
- G. W Randall2
Often soil compaction is considered undesirable for plant growth and may limit soybean yield. The objective of this study was to determine the effect of soil compaction on soybean plant growth, yield, nodulation, and N2 (C2H4) fixation. Field experiments were conducted for 2 years (1976 and 1977) on a Webster clay loam soil (fine-loamy, mixed, mesic Typic Haplaquolls). Plots were compacted by 0, 1, 2, or 3 tractor passes over the same area approximately 2 weeks before planting. Soybean biomass and plant height were measured in 1977, but soil bulk density and soybean seed yield were measured in both years. Nodulation and acetylene reduction activity were measured four times during the season for taproots and two times for lateral roots in both years. Bulk density was increased significantly both years by tractor compaction. In 1976, when extremely dry conditions existed throughout the growing season mean seed yield values were greater on the tractor compacted plots (2,161, 2,106, and 2,283 kg/ha for the 1, 2, and 3 tractor pass treatments, respectively) than on the non-compacted plots (1977 kg/ha), but the yields were not statistically significant. Taproot nodulation and acetylene reduction were also significantly greater on the 2 tractor pass treatment than on the non-compacted plots, but little difference in lateral root nodulation and acetylene reduction was noted.
In 1977, when greater than normal precipitation occurred, compaction decreased significantly plant growth and taproot nodulation and tended to decrease lateral root nodulation. Acetylene reduction was not affected by compaction. The mean seed yield value was greatest in the non-compacted plot (4,117 kg/ha) and the mean values declined with increasing tractor compaction (4,105, 3,955, and 3,854 kg/ha for the 1, 2, and 3 tractor pass treatments, respectively), although the yields were not statistically different. The effect of soil compaction in the spring prior to planting appeared to be dependent on the amount of precipitation in the growing season.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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