Skip to main content
ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #307018
Title: Ridge tillage concentrates potentially mineralizable soil N in the crop row, facilitating maize N uptake

Author
item KANE, DAN - Michigan State University
item SNAPP, SEIGLINDE - Michigan State University
item Davis, Adam

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2014
Publication Date: 12/16/2014
Citation: Kane, D.A., Snapp, S.S., Davis, A.S. 2014. Ridge tillage concentrates potentially mineralizable soil N in the crop row, facilitating maize N uptake. Soil Science Society of America Journal. 79:81-88.

Interpretive Summary: Tight spatial linkage between the supply of plant-available N by agricultural soils and the uptake of N by crops is desirable because it can reduce environmental damage resulting from loss of nitrogen from agricultural systems. Ridge tillage (RT) is an approach to agricultural soil management that moves soil from inter-row areas to raised crop rows. This tillage system has been shown to increase measures of soil quality, such as soil carbon and aggregation, in comparison to chisel plow (CP) systems. However, less is known about the soil N provisioning capacity of this system. We monitored soil potentially mineralizable N (PMN), inorganic N, and plant tissue N across the crop row and inter-row areas in a field study comparing RT and CP systems. Experiments were fully replicated in Urbana, Illinois, and Mason, Michigan, during the 2012 growing season. At both sites, PMN was concentrated in the crop row in the RT system, whereas PMN was spread more evenly across the crop row and inter-row areas in the CP system. Soil inorganic N uptake by maize was greater in the RT than the CP system at both sites. These results suggest that RT can establish soil functional zones with distinct N profiles, and that the concentration of PMN in the crop row may increase the efficiency of N provisioning in RT systems, relative to CP systems.

Technical Abstract: Ridge tillage (RT) has been shown to promote increases in soil carbon and aggregation at greater rates than conventional tillage, but less is known about the soil N provisioning capacity of this system. Using a spatially intensive sampling design, we monitored soil potentially mineralizable nitrogen (PMN), inorganic N, and plant tissue N across the row/inter-row space in a field study comparing ridge tillage and chisel plow (CP) systems. Experiments were fully replicated at two sites in Urbana, Illinois (IL) and Mason, Michigan (MI) during the 2012 growing season. At both sites, a strong interaction effect of Tillage x Row Position was observed for PMN (IL, p=0.005; MI, p=0.02) with higher levels of PMN in the in-row (IR) position than off-row (OR) and between-row (BR) positions of RT treatments following re-ridging. A similar Tillage x Position effect was seen for both soil inorganic N at both sites (IL, p=0.007; MI, p=0.02) and ion exchange resin N at the MI site (p=0.07). Plant tissue analyses indicated a significant RT advantage at both sites (IL, p=0.04; MI, p=0.02), and a structural equation modeling (SEM) analysis indicated that PMN at the 0-5 cm depth in the IR position following re-ridging had a significant effect on inorganic N at the same position and, in turn, a strong influence on plant tissue N (CFI=0.86, SRMR=0.11, Akaike wt.=1). Overall, our results suggest that RT can establish soil functional zones (SFZ) with distinct N profiles and that the relocation of PMN in-row may increase the spatial efficiency of N provisioning relative to conventional tillage.