B. Are there spatial or temporal differences in above ...

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Litter bag spatial positions for RT and CP: A. Row, B. Mid-Ridge, and C. Interrow

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Figure 7. Cereal rye litter remaining as a function of treatment, spatial position, and time. The micro-topography and distance from crop row in the ridge-tillage system did not affect the rates of above-ground litter decomposition.

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Figure 6. Vetch litter remaining as a function of treatment, spatial position, and time. The proximity of the litter to the crop row and the micro-topography of the ridge-tillage system did not affect rates of above-ground litter decomposition.

In 2012, plant heights in all treatments were lower than in the previous year.

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During the ridging process, the ridging implement may sever the crop’s lateral roots.

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Conclusions. In dry years, maize grown in a ridge-tillage system out yielded chisel plow. This finding was further supported with higher leaf chlorophyll content

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in ridge-tillage. When cover crops were incorporated without nitrogen maize yields were reduced. Prior to ridging, both root biomass and shoot growth were greatest in ridge-tillage. Following ridging, fertility was a significant factor for shoot height, while we found no differences in root biomass. Taken together, these results suggest early root development, stimulated by either zonal tillage or labile N, can enhance crop productivity even under dry conditions.

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Sub-row micro-topgraphy did not affect above-ground cover crop decomposition in dry conditions. Moisture levels are highly correlated with rates of decomposition. There were no differences in soil moisture across the row transects (not shown here) which likely limited decomposer colonization. We plan to further investigate the soil food web communities across the rows to determine if distinct faunal and microbial communities develop over time.

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B. Root cores (0– 20 cm deep) and plant heights were collected from all treatments without cover crops twice: 1) pre-ridge and 2) post-ridging. (subsamples = 3)

Pre-Ridge: Tillage*Fertilization (p = 0.0127) Post-Ridge: No treatment differences

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Peoples, Sadie Smith, Robert Bennett, Lucie Worthen, Keith Scalines, Nick Warren, and Tessa Wheeler for their assistance in data collection. Funded by he USDA AFRI Climate Change Adaptation and Mitigation Program.

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A. Litter bags containing either winter rye or vetch were deployed the day after ridging (July 3, 2012: 184th Julian Day). Bags were collected 11 days and 28 days after deployment.

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Acknowledgments. We would like to thank Cynthia Kallenbach, Matt

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1. Kaspar T. C., H. J. Brown, and E. M. Kassmeyer. 1991. Corn Root Distribution as Affected by Tillage, Wheel Traffic, and Fertilizer Placement. Soil Science Society of America Journal 55:1390-1394; 2. Liebig M. A., A. J. Jones, L. N. Mielke, and J. W. Doran. 1993. Controlled Wheel Traffic Effects on Soil Properties in Ridge Tillage. Soil Science Society of America Journal 57:1061-1066.

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N0: No Fertilization

N+: Fertilization

Pre-Ridge: Tillage (p = 0.0097) Post-Ridge: Fertilization (p < 0.001)

Figure 4. Soil moisture did not differ between the two tillage systems.

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110 lbs/acre Aroostook Cereal Rye

Figure 5. Maize shoot heights (top) and root biomass (bottom) pre- and postridging. Prior to ridging, maize plants were taller in the ridge-tillage (RT) treatment and root biomass was greatest in the fertilized RT treatment. After ridging, there were no differences in root biomass; however, the fertilized treatments were taller.

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CP: Chisel Plow No CC: No Cover Crop

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Figure 2. Maize yields were higher in the ridge-till (RT) treatment than the uniformly-tilled CP treatment. We also observed a significant cover crop by fertility interaction.

Ridge-tillage time series. (a) Corn ridges are permanent from year-to-year. Plant residues accumulate in interrows. (b) Ridging incorporates plant residues and places them in the row, above the crop rhizosphere. (c) This process creates micro-topographical variation at the sub-m2 level.

C. Leaf nitrogen content was collected with a SPAD meter three times: 1) pre-ridge, 2) post-ridging, and 3) at reproductive maturity. (subsamples = 3)

B. Are there spatial or temporal differences in above-ground litter decomposition in ridge tilled versus uniformly tilled systems?

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Springs, PA. The design was a fully crossed three factor split-plot randomized complete block with four replications.

A. Do ridge-tillage, cover crops, and fertilization interact to influence maize productivity?

References.

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Methods. The experiment was established in 2011 at the Russell Larson Agricultural Research Center in Rock

be necessary to ensure a stable food supply in the face of increasing climate variability. One potential strategy for managing for climate variability is to maintain distinct zones within crop field soils where agroecosystem processes can be enhanced or manipulated separately from other zones. Ridge-tillage is a zonal management system that concentrates residues (cover crops and other organic materials) in the crop row where decomposition and nutrient cycling processes may be more spatially and temporally synchronous with crop demand. Ridge-tillage also results in greater topographic zonation compared to uniform tillage practices (e.g., chisel or moldboard plow), and this may further ameliorate the impacts of extreme weather events (droughts and floods). Zonal management strategies such as ridge tillage may benefit cash crops via incorporation of plant residues and through effects on soil organic matter, soil moisture and standing root mass over time1,2. Our research addressed the following questions:

Tillage (P = 0.0001) Fertilization ( P < 0.0001)

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of Natural Resources & the Environment, University of New Hampshire, Durham, New Hampshire b Department of Plant Sciences, The Pennsylvania State University, University Park, Pennsylvania c Department of Biology, Brigham Young University, Provo, Utah

Background. Identifying management strategies that maintain or improve crop yield stability will

Figure 3. Maize leaf tissue chlorophyll content was affected by both tillage system and fertilization and was highest in the fertilized ridge-till (RT) treatment.

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Lesley W. Atwooda*, Richard G. Smitha, David A. Mortensenb & Roger Koidec a Department

Figure 1. Air temperature and precipitation during the study period. 2012 was a relatively dry year

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Zonal tillage boosts maize yields, but has little effect on above-ground litter decomposition