Simulated nitrogen dynamics and nitrate leaching in a perennial grass ley

1988 ◽  
Vol 105 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Lars Bergström ◽  
Holger Johnsson
Keyword(s):  
Nitrate Leaching ◽  
Perennial Grass ◽  
Nitrogen Dynamics ◽  
Grass Ley

scholarly journals WANDA, a regional dynamic nitrogen model (With Aggregated Nitrogen DynAmics) for nitrate leaching from forests

2004 ◽  
Vol 8 (4) ◽  
pp. 803-812 ◽  
Author(s):  
A. Tietema
Keyword(s):  
Nitrate Leaching ◽  
Regional Scale ◽  
C:N Ratio ◽  
Nitrogen Dynamics ◽  
Organic Layer ◽  
Water Fluxes ◽  
Forest Stands ◽  
Natural Ecosystems ◽  
Nitrogen Model ◽  
Nitrate Concentrations

Abstract. Nitrate concentrations in recently infiltrated groundwater in forested areas in the Netherlands are slowly increasing towards the EU limit of 50 mg NO3 l–1. The origin of this nitrate is thought to be leaching from nitrogen (N) saturated semi-natural ecosystems in these areas. To simulate nitrate leaching on a regional scale, the empirical model WANDA (a regional nitrogen model With Aggregated Nitrogen DynAmics) is introduced. The model is built around the concept that in forests the C:N ratio of the organic layer is indicative of the amount of nitrate leaving the system in drainage. WANDA was tested on a regional dataset of an infiltration area of 10 km2. This infiltration area consisted of 350 forest stands draining to the catchment "Edese Bos" used by a drinking water company. In 75 of the 350 forest stands the C:N ratio of the organic layer was measured. In 30 of these 75 stands, the nitrate concentrations below the rooting zone were measured. A hydrological model calculated water fluxes. The C:N ratio of the 75 stands ranged from 15.7 to 31.3 g C g–1 N. Scots pine stands had the highest C:N ratios in the organic layer. Nitrate concentrations varied in the 30 stands from 0.6 to 70 mg NO3 l–1. The nitrate concentrations in the Douglas fir stands were higher, and in the beech stands lower, than those observed in the locations with other tree species. WANDA predicted nitrate concentrations well, but improvements are required to simulate nitrate fluxes. The simulation of the water fluxes in WANDA is probably where more focussed modelling effort is now required. Keywords: nitrogen, nitrate, forest, model, WANDA, C:N ratio, organic layer

Acidification under grazed annual and perennial grass based pastures

1990 ◽  
Vol 30 (4) ◽  
pp. 539 ◽  
Author(s):  
AM Ridley ◽  
WJ Slattery ◽  
KR Helyar ◽  
A Cowling
Keyword(s):  
Nitrate Leaching ◽  
Acid Soil ◽  
Perennial Grass ◽  
Acid Soils ◽  
Alkaline Soil ◽  
Management Options ◽  
Acid Addition ◽  
Addition Rate ◽  
Fertiliser Application ◽  
Alkali Addition

Soil samples to a depth of 60 cm were collected from adjacent, 39-year-old, phalaris-based and annual pasture fields on an acid soil at Rutherglen, north-eastern Victoria. The fields had similar histories of fertiliser application and stock enterprise. Minimum net acid addition rates were determined under both pasture types, and the soil under annual pasture showed greater acidification. Carbon cycle acid addition contributed 1.3 1 and 1.36 kmol H+/ha.year to net acid addition on annual and phalaris pastures, respectively. Because slow alkaline soil reactions in the field contribute to buffering capacity on an acid soil and lead to underestimation of net acid addition rate and nitrate leaching, estimates of such reactions were made for both pasture types. If correct assumptions were used nitrate leaching was substantial under both pasture types but was reduced by 1.01 kmol H+/ha.year under phalaris pasture. This suggests that perennial grass based pastures can be used to reduce acidification on pastoral soils. Alkali addition to counteract net acidification may be necessary on acid soils to maintain management options for growing aluminium-sensitive species.

scholarly journals Perennial grass ley rotations with annual crops in tropical Africa: A review

2021 ◽  
Author(s):  
C. S. Wortmann ◽  
A. Bilgo ◽  
C. K. Kaizzi ◽  
F. Liben ◽  
M. Garba ◽  
...  
Keyword(s):  
Perennial Grass ◽  
Tropical Africa ◽  
Annual Crops ◽  
Grass Ley

scholarly journals Nitrogen and phosphorus losses in surface runoff and drainage water after application of slurry and mineral fertilizer to perennial grass ley

1998 ◽  
Vol 7 (5-6) ◽  
pp. 569-581 ◽  
Author(s):  
E. TURTOLA ◽  
E. KEMPPAINEN
Keyword(s):  
Surface Runoff ◽  
Perennial Grass ◽  
Mineral Fertilizer ◽  
Fine Sand ◽  
Drainage Water ◽  
First Year ◽  
Nitrogen And Phosphorus ◽  
N Losses ◽  
Total Runoff ◽  
Grass Ley

Losses of nitrogen (N) and phosphorus (P) from perennial grass ley on a fine sand soil were studied with five treatments: no fertilizer (1), cow slurry applied in autumn (2), winter (3) or spring (4), and mineral fertilizer applied in spring (5). For N, the total amounts applied (1992-96) were 0, 772, 807, 805 and 510 kg ha-1 and for P 0, 141, 119, 143 and 107 kg ha-1, respectively. In the first year (establishment of the ley, 1992-93), N losses (drainage + surface runoff) were slightly higher after application of slurry in autumn (with immediate ploughing, treatment 2) than in treatments 1, 4 and 5 (21 kg ha-1 vs. 17 kg ha-1), but the respective P losses (0.7-0.9 kg ha-1) were not affected. During the ley years (1993-96) the N and P losses were increased by surface application of fertilizers and by abundance of surface runoff (83-100% of the total runoff). Nutrient losses were extremely high after slurry application in autumn and winter, accounting for 11% and 33% of the applied N and 17% and 59% of the applied P, respectively. The N losses during the ley years from treatments 1-5 were 13, 62, 191, 23 and 24 kg ha-1, where the proportion of NH4-N was 21, 49, 56, 33 and 39%. The respective P losses were 0.73, 16, 54, 4.2 and 4.0 kg ha-1, where the proportion of PO4-P was 52, 85, 77, 68 and 64%.;

Runoff of faecal microorganisms and nutrients from perennial grass ley after application of slurry and mineral fertiliser

2001 ◽  
Vol 43 (12) ◽  
pp. 143-146 ◽  
Author(s):  
H. Heinonen-Tanski ◽  
J. Uusi-Kämppä
Keyword(s):  
Surface Runoff ◽  
Perennial Grass ◽  
Early Summer ◽  
Soil Slurry ◽  
Runoff Water ◽  
One Year ◽  
Surface Spread ◽  
Slurry Injection ◽  
Surface Spreading ◽  
Grass Ley

Perennial grass was fertilised with cattle slurry either surface-spread or injected into the soil. Slurry was spread once (early summer) in 1996 and 1997 and twice (both summer and autumn) in 1998 and 1999. The control was mineral fertilisation in summer. Faecal microbial numbers in surface runoff water were very high in late June 1998 soon after very heavy rains even though the last slurry application had been made almost one year earlier. There was no clear difference between slurry spreading methods. Autumn spreading of slurry lead to high microbial levels in runoff waters and water hygiene was protected better by slurry injection than by surface spreading. In spring, after snow melt, some faecal microorganisms were found in surface runoff water and the numbers of faecal microorganisms were less from plots with slurry surface spreading than those with slurry-injection. Losses of total phosphorus (TP) and total nitrogen (TN) in surface runoff were 2.7 and 7.7 kg/ha respectively from grass with surface-spread slurry in winter 1998-1999. The injection of slurry decreased TP and TN runoff by an average of 81% and 73% respectively. In 1999 there was little runoff because the summer was sunny and dry.

Effects of Tied Ridges, Terraces and Grass Leys on a Lateritic Soil in Kenya

1967 ◽  
Vol 3 (2) ◽  
pp. 89-98 ◽  
Author(s):  
H. C. Pereira ◽  
P. H. Hosegood ◽  
M. Dagg
Keyword(s):  
Water Conservation ◽  
Soil Structure ◽  
Cynodon Dactylon ◽  
Perennial Grass ◽  
High Standard ◽  
Lateritic Soil ◽  
Progressive Reduction ◽  
Arable Crops ◽  
Wilting Point ◽  
Grass Ley

SummaryIn a study of soil and water conservation systems for high-altitude Kenya farming, control of accelerated erosion in two arable crops per year for six years was achieved by contour-ploughing and tied-ridging. The Kikuyu red loam latosol lay on 10 per cent and 12 per cent slopes under rainfall of intensities often exceeding 2 inches per hour. Soil structure measurements showed progressive reduction in the acceptance rate of rainfall, but gulley erosion occurred only in the absence of ties. Six years of intensive arable cultivations were compared with rotations having two, three or four years of perennial grass ley, with and without protection by Nichols terraces. Runoff, measured through Parshall flumes, was heaviest from well-established grass immediately after intensive grazing. Productivity was highest under grass. With a basal dressing of one hundred weight of double supers, 10 acres of Cynodon dactylon carried 20 Zebu steers for seven months without supplementation and showed a liveweight gain of 1·1 lb per steer per day. Grazing was reduced by failures in establishment of short legs. The grass depleted soil moisture to wilting point to a depth of ten feet within six months of planting and annually thereafter. Water use was approximately the same as total rainfall. Results, applicable locally, indicate a limit of four years duration for arable and a minimum of five years duration for pastures. Terraces can only be replaced by a high standard of management and skilled cultivation.

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