Impact of Cover Crops on Soil Physical Properties Newell R. Kitchen Matt Volkmann October 21, 2009
Cover: blanket, canopy, cloak, hood, layer, shield, overlay, veil, cap
On May 1, 1917 in Columbia, MO the first erosion plot research in the US was initiated. WHY Columbia?
Historical Loss of Soil from Erosion • Average 5 inches of soil loss over the whole field • Extreme Loss > 16 inches of soil loss in localized areas • Over 150 years…. between 5 and 6 tons/year
Lost topsoil from erosion • Lost organic matter • Lost soil structure • Lower fertility What good is “cover” when you’ve lost 60-90% of the function of that original soil?
These degraded soils have lost so much of their original function……in many ways they are nearly dead and in need of life support!
What are the Hidden (i.e., below ground) Impacts Of Cover Crops?
Mulch tillage, Corn-soybean rotation (MTCS) No-till, Corn-soybean-wheat rotation (NTCSW cover)
a a a b How about Soil Hydraulic Conductivity?
NT CSWcover MT CS NT CS How about Infiltration?
HAY CRP CRP Permanent grass management 2 Conservation Reserve Program (CRP) systems: No inputs Species: Tall fescue, orchard grass, red clover or warm season grasses • Hay: Hay crop, N 90 kg/ha, Lime, P, and K by soil test Species: White clover, orchard grass, Canadian wildrye, big bluestem. CRP HAY
hay (cool & warm) CRP (cool) CRP (warm)
How about Total Soil Organic Carbon and Nitrogen? Soil depth, m
Results – Temporal Differences in SQIs Highlighted items are significantly different between samplings
Typical Positive Impacts from Cover Crops on Soil Physical Properties • Increased soil organic matter • Enhanced infiltration • Enhanced aeration • Improved soil structure/aggregation • Decreased soil strength** • Preventive of soil compaction • Reduced evaporation potential