Measurement and prediction of nitrogen loss by simulated erosion events on cultivated forest soils of contrasting structure

2005 ◽  
Vol 83 (2) ◽  
pp. 204-217 ◽  
Author(s):  
P.C. Teixeira ◽  
R.K. Misra
Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1155
Author(s):  
Peter Baas ◽  
Jennifer D. Knoepp ◽  
Jacqueline E. Mohan

Understanding the dominant soil nitrogen (N) cycling processes in southern Appalachian forests is crucial for predicting ecosystem responses to changing N deposition and climate. The role of anaerobic nitrogen cycling processes in well-aerated soils has long been questioned, and recent N cycling research suggests it needs to be re-evaluated. We assessed gross and potential rates of soil N cycling processes, including mineralization, nitrification, denitrification, nitrifier denitrification, and dissimilatory nitrate reduction to ammonium (DNRA) in sites representing a vegetation and elevation gradient in the U.S. Department of Agriculture (USDA) Forest Service Experimental Forest, Coweeta Hydrologic Laboratory in southwestern North Carolina, USA. N cycling processes varied among sites, with gross mineralization and nitrification being greatest in high-elevation northern hardwood forests. Gaseous N losses via nitrifier denitrification were common in all ecosystems but were greatest in northern hardwood. Ecosystem N retention via DNRA (nitrification-produced NO3 reduced to NH4) ranged from 2% to 20% of the total nitrification and was highest in the mixed-oak forest. Our results suggest the potential for gaseous N losses through anaerobic processes (nitrifier denitrification) are prevalent in well-aerated forest soils and may play a key role in ecosystem N cycling.


Nature ◽  
2002 ◽  
Vol 418 (6898) ◽  
pp. 604-604
Author(s):  
Tom Addiscott ◽  
Phil Brookes
Keyword(s):  

Nature ◽  
2002 ◽  
Vol 418 (6898) ◽  
pp. 604-604 ◽  
Author(s):  
Nico van Breemen
Keyword(s):  

The results of long-term research on the influence of main indicators on their agro-resource potential are summarized on gray forest soils of the upper Volga region. For the conditions of the Vladimir Opolie, the probable yield of biomass and the main products of field crops were calculated at different coefficients ofphotosynthetic active radiation (FAR) use. Calculations of the main product yields are made taking into account the distribution of biomass to by-products and crop-root residues. For field crops of the studied crop rotations, the coefficients of precipitation utilization are estimated. They varied from 44 to 71%, depending on the crop rotation culture. On the slope of the southern exposure when cultivating winter cereals and perennial grasses, the main moisture losses were observed in the spring during snowmelt, when growing spring crops and potatoes, they were close in the autumn and spring periods. The sizes of moisture use by crops depending on the fertilizer systems for the creation of 1 C of grain units (g.u.) and from sub-arable layers are determined. In comparison with the liming background, the use of organic fertilizers reduced the water consumption coefficient from 9.6 to 8.5 mm/C g.u., their combination with a single dose of NPK - up to 7.3, and with a double dose - up to 6.8 mm / C g.u. Based on the amount of moisture used by crops, their possible yields are calculated. In spring crops, the amount of precipitation consumed (326-356 mm) corresponds to the use of 2.7-3% of the FAR and provides 54-60 C/ha of grain, in winter rye and wheat - about 4% of the FAR (yield 71-80 C/ha). In perennial grasses for 2 mowing, the moisture consumed is enough to use about 3% of the FAR., in potatoes -1.5%.


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