Physical Characteristics of Le Sueur Clay Loam Soil Following No-till and Conventional Tillage1
- C. J. Gantzer and
- G. R. Blake2
Although the effects of no-till on crop yields has been widely investigated, there are virtually no data on its physical effects on clay loam soils like those in the Corn Belt. In order to compare the effects of no-till with conventional fall plow tillage on a south-central Minnesota clay loam soil (Aquic Argiudoll), we measured some soil physical properties 6 years after beginning a field experiment with corn (Zea mays L.). Data show that soil under no-till had significantly greater bulk density, both in spring and fall, for samples in the surface 30 cm. Densities of no-till soil ranged from 1.24 to 1.32 g/cm3 in in contrast to those of conventional tillage, which ranged from 1.05 to 1.12 g/cm3. Air-filled porosities of surface samples under no-till were lower at all potentials measured. At −100 rob, no-till averaged 0.143 cm3/cm3 compared to 0.198 cm3/cm3 for conventional tillage. Mean number of channels 1 mm and greater created by earthworms and decomposed rootlets were significantly greater for no-till, ranging from 666 to 1,732/m2 compared to 243 to 1,475/m2 for conventional tillage. Volumetric water contents were also greater for no-till surface samples, ranging from 0.35 to 0.28 cm3/cm3 vs. 0.31 to 0.25 cm3/cm3 for conventional tillage. Saturated hydraulic conductivities of spring surface samples were lower under no-till than conventional tillage averaging 14.6 cm/hour and 38.2 cm/hour, respectively. Generally. differences in measured parameters between treatments were smaller for samples collected in fall before harvest, than those in spring. Significant differences for tillage treatment were not found below 30 cm depth. At high water potentials, lower porosity under no-till may restrict gaseous exchange and create conditions unfavorable for germination and seedling development. However, higher number of biochannels in the no-till soil may compensate for this reduced exchange.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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