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Agricultural Science

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Nitrogen cycling

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Effects Of In Situ Freezing On Soil Net Nitrogen Mineralization And Net Nitrification In Fertilized Grassland Of Northern China, X. Zhang, W. Bai, Frank S. Gilliam, Q. Wang, X. Han, L. Li Sep 2012

Effects Of In Situ Freezing On Soil Net Nitrogen Mineralization And Net Nitrification In Fertilized Grassland Of Northern China, X. Zhang, W. Bai, Frank S. Gilliam, Q. Wang, X. Han, L. Li

Frank S. Gilliam

Effects of soil freezing on nitrogen (N) mineralization have been the subject of increased attention in the ecological literature, though fewer studies have examined N mineralization responses to successive mild freezing, severe freezing and cyclic freeze–thaw events. Even less is known about relationships of responses to soil N status. This study measured soil N mineralization and nitrification in the field along an experimental N gradient in a grassland of northern China during the dormant season (October 2005–April 2006), a period in which freezing naturally occurs. Net N mineralization exhibited great temporal variability, with nitrification being the predominant N transformation process. …


Dryland Soil Nitrogen Cycling Influenced By Tillage, Crop Rotation, And Cultural Practice, Upendra M. Sainju, Andrew W. Lenssen, Thecan Caesar-Tonthat, Jalal D. Jabro, Robert T. Lartey, Robert G. Evans, Brett L. Allen Jul 2012

Dryland Soil Nitrogen Cycling Influenced By Tillage, Crop Rotation, And Cultural Practice, Upendra M. Sainju, Andrew W. Lenssen, Thecan Caesar-Tonthat, Jalal D. Jabro, Robert T. Lartey, Robert G. Evans, Brett L. Allen

Andrew W. Lenssen

Management practices may influence dryland soil N cycling. We evaluated the effects of tillage, crop rotation, and cultural practice on dryland crop biomass (stems and leaves) N, surface residue N, and soil N fractions at the 0–20 cm depth in a Williams loam from 2004 to 2008 in eastern Montana, USA. Treatments were two tillage practices (no-tillage [NT] and conventional tillage [CT]), two crop rotations (continuous spring wheat [Triticum aestivum L.] [CW] and spring wheat-barley [Hordeum vulgaris L.] hay-corn [Zea mays L.]-pea [Pisum sativum L.] [W-B-C-P]), and two cultural practices (regular [conventional seed rates and plant spacing, conventional planting date, …


Tillage And Cropping Sequence Impacts On Nitrogen Cycling In Dryland Farming In Eastern Montana, Usa, Upendra M. Sainju, Thecan Caesar-Tonthat, Andrew W. Lenssen, Robert G. Evans, Robert Kolberg May 2009

Tillage And Cropping Sequence Impacts On Nitrogen Cycling In Dryland Farming In Eastern Montana, Usa, Upendra M. Sainju, Thecan Caesar-Tonthat, Andrew W. Lenssen, Robert G. Evans, Robert Kolberg

Andrew W. Lenssen

Information on N cycling in dryland crops and soils as influenced by long-term tillage and cropping sequence is needed to quantify soil N sequestration, mineralization, and N balance to reduce N fertilization rate and N losses through soil processes. The 21-yr effects of the combinations of tillage and cropping sequences was evaluated on dryland crop grain and biomass (stems + leaves) N, soil surface residue N, soil N fractions, and N balance at the 0–20 cm depth in Dooley sandy loam (fine-loamy, mixed, frigid, Typic Argiboroll) in eastern Montana, USA. Treatments were no-tilled continuous spring wheat (Triticum aestivum L.) (NTCW), …