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Tillage and Compaction Impact on Soil Aggregate Associated Properties

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Tillage and Compaction Impact on Soil Aggregate Associated Properties Tillage and Compaction Impact On Soil Aggregate Associated Properties Kenan Barik, Ataturk University, Turkey and Randall Reeder, Alan Sundermeier, Yogi Raut, Rafiq Islam, Stacey Reno, and Jim Hoorman Ohio State University, Ohio Kenan Alan Jim Rafiq Heavy farm machinery compacts the soil, both on tilled ground and no-tilled ground. Plowing and subsoiling degrade soil structure by dispersing macro-aggregates. Tillage breaks up roots, fungal hyphae and other important living organisms. No-Till minimizes soil erosion, benefits soil biology, and increases soil aggregate stability. Data on soil physical properties is useful to evaluate a soil. Conclusions Compaction from a big grain cart (18 Mg/axle) affected soil aggregate properties on both continuous no-till and annually subsoiled plots. No-Till, to some extent, can improve the aggregate properties of soil. Compaction research since 1988 Materials and Methods Field experiment was established on Hoytville clay loam in 3 x 2 factorial arrangement of RCB design in Wood County, northwest Ohio. Materials and Methods The factors were: 1) Compaction: control, 9 and 18 Mg/axle loads 2) Tillage: no-till and annual tillage (subsoiling) Compaction with a 600-bu grain cart (full = 18 Mg/axle; half full = 9 Mg/axle) Results and Discussion Compaction caused a significant decrease in: •Concentration of aggregates 1-2 mm •Concentration of >2 mm, and •Stability of macro- and micro-aggregate, MWD, GMD, and ratio of macro- and micro- aggregates. Compaction increased concentration of smaller aggregates <0.053 mm. More compaction means more small aggregates… 20 15* 10 * * 5 0.125 - 0.25 mm: y= 6.5 + 0.34*X 0.053 - 0.125 mm; y = 5.5 + 0.028*X 2 Aggregate size distribution (%) (%) distribution size Aggregate <0.053 mm: y = 16.6 - 0.1*X + 0.01*X 0 0 5 10 15 20 Soil compaction (Mg) …and fewer large aggregates 30 25 20 * 15 >2 mm: y = 7.6 - 0.14*X 1 - 2 mm: y = 20.1 +0.06*X -0.016*X2 0.5 - 1 mm: y 24.2 - 0.13*X 10 0.25 - 0.5 mm: y = 18.3 + 0.044*X * 5 Aggregate size distribution (%) size distribution (%) Aggregate 0 0 5 10 15 20 Soil compaction (Mg) Compaction increased the cone penetration resistance and bulk density. The impact was mainly with the heavier axle load (18 Mg). Cone penetrometer resistance (depth, 0-30 cm) 2500 2000 1500 (kPa) 1000 CT: y = 1190.2 - 15.8*X +2.5*X2 500 NT: y= 1629 - 21.1*X + 2.6*X2 Penetration resistance 0 0 5 10 15 20 Soil compaction (Mg) Cone penetrometer resistance (depth, 0-30 cm) 2500 2000 1500 (kPa) 1000 CT: y = 1190.2 - 15.8*X +2.5*X2 500 NT: y= 1629 - 21.1*X + 2.6*X2 Penetration resistance 0 0 5 10 15 20 Soil compaction (Mg) Compacting load had more effect near surface 2500 2000 1500 (kPa) 1000 0 - 15 cm: y = 1254.6 - 24.7*X + 2.9*X2 500 15 - 30 cm: y = 1564.6 - 12.3*X + 2.1*X2 Penetration resistance 0 0 5 10 15 20 Soil compaction (Mg) No-Till increased cone penetration resistance and soil bulk density compared with subsoiling. Cone Penetrometer resistance 2500 Effects LSDp<0.05 Tillage ** 0 - 15 cm Soil depth ** 15 - 30 cm 2000 1500 kPa) 1000 500 Penetration resistance 0 CT NT Tillage * 95% **99% ***99.9% Soil Bulk Density 1.8 Effects LSDp<0.05 0-15 cm ) Tillage ** 15-30 cm -3 Soil depth ** 1.6 1.4 1.2 Soil bulk density (g cm 1.0 CT NT Tillage 9 Mg axle load had more effect on soil density near surface; Adding 9 Mg did not double the change in density. Deeper soil started at higher density; linear relationship for axle load 1.7 ) 1.6 -3 1.5 1.4 1.3 0-15 cm: y = 1.41 + 0.18(1-exp(-0.11*X)) 1.2 15-30 cm: y = 1.55 + 0.0045*X 1.1 Soil bulk (g cm density 1.0 0 5 10 15 20 Soil compaction (Mg) No-Till significantly increased: • Proportion of >2 mm size aggregates • Macro- and micro-aggregate stability • Mean Weight Diameter (MWD) • Geometric Mean Diameter (GMD) Change in soil aggregate associated properties decreased significantly with depth. With No-Till, more large aggregates, fewer small ones 25 >2 mm 1-2 mm 0.5-1 mm 0.25-0.5 mm 20 0.125-0.25 mm 0.053-0.125 mm 0.053 mm 15 * 10 #* * #* 5 Aggregate size (%) distribution Aggregate 0 CT NT Tillage No-Till increased Stability of Macro-Aggregates 80 MacAS* MicAS * 70 AS* 60 50 40 30 Aggregate stability (%) stability Aggregate 20 CT NT Tillage No-till increased MWD and GMD 650 MWD * 600 GMD * 550 500 450 400 Aggregate size (um) size Aggregate 350 300 CT NT Tillage As mean weight diameter (MWD) of aggregates increased: Macro-aggregate stability increased and Micro-aggregate stability decreased. 100 80 60 Macrogrregate stability: y = -42.7 - 0.37*X - 0.0003*X2 Microaggregate stability: y = 42.3 - 0.37*X + 0.0003*X2 40 20 Aggregate stability (%) 0 400 450 500 550 600 650 700 Mean weight diameter (um) No significant interactive effects of soil depth with compaction or tillage on aggregate properties. No significant impact of compaction x tillage interaction on soil aggregate size. Conclusions Compaction consistently affected soil aggregate properties, for both no-till and subsoiling systems. No-Till, to some extent, can improve the aggregate properties of soil. Tillage and Compaction Impact On Soil Aggregate Associated Properties Kenan Barik, Ataturk University, Turkey Randall Reeder, Alan Sundermeier, Jim Hoorman, Yogi Raut, Rafiq Islam and Stacey Reno Ohio State University .
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