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USDA-ARS, Appalachian Soil & Water Conservation Res. Lab., P.O. Box 867, Beckley, WV 25802.
* Corresponding author (Email: tstaley{at}asrr.arsusda.gov).
Few studies have compared N utilization by maize (Zea mays L.) under conventional tillage (CT) and no-tillage (NT) in the Appalachian region. Silage production (TDM) and fertilizer N and soil N uptake, were investigated in a 3-yr study on a Gilpin silt loam (fine-loamy, mixed, mesic Typic Hapludult) in West Virginia previously cropped to pasture. 15N-depleted N fertilizer was band-applied, within-row, at 0, 56, 112, and 224 kg N ha–1, 4 wk after planting. Tillage method did not affect silage production, N concentration or total N uptake at any N rate. Maximal silage production under NT (13.2 Mg ha–1) was calculated to require just 24 kg ha–1 more fertilizer N than under CT (12.6 Mg ha–1). Fertilizer N uptake (kg ha–1) was similarly unaffected by tillage method, with annual fertilizer N use efficiencies (% recovery) of 55, 54, and 49% under NT, and 57, 57, and 48% under CT, at application rates of 56, 112, and 224 kg ha–1, respectively. Similar percentages for cumulative fertilizer N use efficiencies, which account for any labeled N carried over from year to year, suggest that there was little residuum available to the crop, particularly at near-optimal N rates. Soil N uptake decreased by 17% with N additions below (56 kg ha–1) or above (224 kg ha–1) the optimum, but was generally unaffected by tillage method. These similarities between NT and CT for maize silage production and N use, despite using a management system contrived to show differences, emphasize the importance of edaphic and climatological factors in predicting N responses under various tillage methods. Nonetheless, these resuits show that reasonably high levels of silage can be produced without excessive fertilizer N requirements (
170 kg N ha–1) or losses (< 50%) when pastures are converted to NT maize.
Received for publication September 20, 1994.
This article has been cited by other articles:
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T.E. Staley Soil microbial biomass alterations during the maize silage growing season relative to tillage method Soil Sci. Soc. Am. J., November 1, 1999; 63(6): 1845 - 1847. [Abstract] [Full Text] [PDF] |
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