Cropping Intensity Effects on Physical Properties of a No-till Silt Loam Soil

Authors: Benjamin, Joseph; Mikha, Maysoon; Nielsen, David; Vigil, Merle; Calderon, Francisco; Henry, William

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2007
Publication Date: 7/1/2007
Citation: Benjamin, J.G., Mikha, M.M., Nielsen, D.C., Vigil, M.F., Calderon, F.J., Henry, W.B. 2007. Cropping Intensity Effects on Physical Properties of a No-till Silt Loam Soil. Soil Science Society of America Journal 71:1160-1165.

Interpretive Summary: No-till cropping systems in the semi-arid west have the potential to increase organic carbon in the soil profile and improve soil physical properties by increasing cropping intensity and crop diversity. A study was conducted to test the hypothesis that increasing cropping intensity will improve selected soil physical properties. Soil conditions from winter wheat-summer fallow plots were compared with soil conditions under wheat-corn-fallow, wheat-corn-sunflower-fallow, wheat-corn-millet and a perennial grass/legume mix. Bulk density, pore size distribution, and saturated hydraulic conductivity were measured in 1997, 2001 and 2005. Only perennial grass improved soil physical properties at a different rate from the wheat-fallow rotation. Bulk density in the grass plots decreased more quickly and to a greater extent than any of the annually cropped systems. Saturated hydraulic conductivity increased more in the grass plots than in the annually cropped plots. Changing soil physical properties by increasing cropping intensity may take decades to become apparent. The advantages of perennial vegetation include less annual surface compaction from planting operations and root systems that remains in the soil over a longer period of time to create a more stable, continuous pore network.

Technical Abstract: No-till cropping systems in the semi-arid west have the potential to increase organic carbon in the soil profile and improve soil physical properties by increasing cropping intensity and crop diversity. A study was conducted to test the hypothesis that increasing cropping intensity will improve selected soil physical properties. Soil conditions from winter wheat (Triticum aestivum L.)-summer fallow (WF) plots were compared with soil conditions under wheat-corn (Zea mays L.)-fallow (WCF), wheat-corn-sunflower (Helianthus annus L.)-fallow (WCSF), wheat-corn-millet (Panicum miliaceum L.) (WCM) and a perennial grass/legume mix. Bulk density, pore size distribution, and saturated hydraulic conductivity were measured in 1997, 2001 and 2005. Only perennial grass improved soil physical properties at a different rate from the wheat-fallow rotation. Bulk density in the grass plots decreased from 1.39 g cm-3 in 1997 to 1.25 g cm-3 in 2005. Bulk density in the annually cropped plots decreased from 1.38 g cm-3 to 1.30 g cm-3 over the same time period. Saturated hydraulic conductivity increased in the grass plots from 27 mm h-1 in 1997 to 98 mm h-1 in 2005. Saturated hydraulic conductivity in the annually cropped systems increased from about 14 mm h-1 to about 35 mm h-1 over the same time period. Changing soil physical properties by increasing cropping intensity may take decades to become apparent. The advantages of perennial vegetation include less annual surface compaction from planting operations and root systems that remains in the soil over a longer period of time to create a more stable, continuous pore network.