scholarly journals Bermudagrass Management in the Southern Piedmont U.S. IV. Soil Surface Nitrogen Pools

2001 ◽  
Vol 1 ◽  
pp. 673-681 ◽  
Author(s):  
Alan J. Franzluebbers ◽  
John A. Stuedemann
Keyword(s):  
Cynodon Dactylon ◽  
Soil Surface ◽  
N Fertilization ◽  
Organic N ◽  
Soil N ◽  
Crimson Clover ◽  
Total Soil ◽  
Soil N Pools ◽  
Total Soil N

The fate of nitrogen (N) applied in forage-based agricultural systems is important for understanding the long-term production and environmental impacts of a particular management strategy. We evaluated the factorial combination of three types of N fertilization (inorganic, crimson clover [Trifolium incarnatum L.] cover crop plus inorganic, and chicken [Gallus gallus] broiler litter pressure and four types of harvest strategy (unharvested forage, low and high cattle [Bos Taurus] grazing pressure, and monthly haying in summer) on surface residue and soil N pools during the first 5 years of ̒Coastal̓ bermudagrass (Cynodon dactylon [L.] Pers.) management. The type of N fertilization used resulted in small changes in soil N pools, except at a depth of 0 to 2 cm, where total soil N was sequestered at a rate 0.2 g ‧ kg–1‧ year–11 greater with inorganic fertilization than with other fertilization strategies. We could account for more of the applied N under grazed systems (76–82%) than under ungrazed systems (35–71%). As a percentage of applied N, 32 and 48% were sequestered as total soil N at a depth of 0 to 6 cm when averaged across fertilization strategies under low and high grazing pressures, respectively, which was equivalent to 6.8 and 10.3 g ‧ m–2‧ year–1. Sequestration rates of total soil N under the unharvested-forage and haying strategies were negligible. Most of the increase in total soil N was at a depth of 0 to 2 cm and was due to changes in the particulate organic N (PON) pool. The greater cycling of applied N into the soil organic N pool with grazed compared with ungrazed systems suggests an increase in the long-term fertility of soil.

The effects of long-term applications of inorganic nitrogen fertilizer on soil nitrogen in the Broadbalk Wheat Experiment

1996 ◽  
Vol 127 (3) ◽  
pp. 347-363 ◽  
Author(s):  
M. J. Glendining ◽  
D. S. Powlson ◽  
P. R. Poulton ◽  
N. J. Bradbury ◽  
D. Palazzo ◽  
...  
Keyword(s):  
N Mineralization ◽  
Inorganic Nitrogen ◽  
Organic N ◽  
Soil N ◽  
Fertilizer N ◽  
Short Term ◽  
N Content ◽  
Total Soil ◽  
Total Soil N

SUMMARYThe Broadbalk Wheat Experiment at Rothamsted (UK) includes plots given the same annual applications of inorganic nitrogen (N) fertilizer each year since 1852 (48, 96 and 144 kg N/ha, termed N1 N2 and N3 respectively). These very long-term N treatments have increased total soil N content, relative to the plot never receiving fertilizer N (N0), due to the greater return of organic N to the soil in roots, root exudates, stubble, etc (the straw is not incorporated). The application of 144 kg N/ha for 135 years has increased total soil N content by 21%, or 570 kg/ha (0–23 cm). Other plots given smaller applications of N for the same time show smaller increases; these differences were established within 30 years. Increases in total soil N content have been detected after 20 years in the plot given 192 kg N/ha since 1968 (N4).There was a proportionally greater increase in N mineralization. Crop uptake of mineralized N was typically 12–30 kg N/ha greater from the N3 and N4 treatments than the uptake of c. 30 kg N/ha from the N0 treatment. Results from laboratory incubations show the importance of recently added residues (roots, stubble, etc) on N mineralization. In short-term (2–3 week) incubations, with soil sampled at harvest, N mineralization was up to 60% greater from the N3 treatment than from N0. In long-term incubations, or in soil without recently added residues, differences between long-term fertilizer treatments were much less marked. Inputs of organic N to the soil from weeds (principally Equisetum arvense L.) to the N0–N2 plots over the last few years may have partially obscured any underlying differences in mineralization.The long-term fertilizer treatments appeared to have had no effect on soil microbial biomass N or carbon (C) content, but have increased the specific mineralization rate of the biomass (defined as N mineralized per unit of biomass).Greater N mineralization will also increase losses of N from the system, via leaching and gaseous emissions. In December 1988 the N3 and N4 plots contained respectively 14 and 23 kg/ha more inorganic N in the profile (0–100 cm) than the N0 plot, due to greater N mineralization. These small differences are important as it only requires 23 kg N/ha to be leached from Broadbalk to increase the nitrate concentration of percolating water above the 1980 EC Drinking Water Quality Directive limit of 11·3mgN/l.The use of fertilizer N has increased N mineralization due to the build-up of soil organic N. In addition, much of the organic N in Broadbalk topsoil is now derived from fertilizer N. A computer model of N mineralization on Broadbalk estimated that after applying 144 kg N/ha for 140 years, up to half of the N mineralized each year was originally derived from fertilizer N.In the short-term, the amount of fertilizer N applied usually has little direct effect on losses of N over winter. In most years little fertilizer-derived N remains in Broadbalk soil in inorganic form at harvest from applications of up to 192 kg N/ha. However, in two very dry years (1989 and 1990) large inorganic N residues remained at harvest where 144 and 192 kg N/ha had been applied, even though the crop continued to respond to fertilizer N, up to at least 240 kg N/ha.

Relationships between biological and chemical measures of N supplying power and total soil N at field scale

1999 ◽  
Vol 79 (2) ◽  
pp. 353-366 ◽  
Author(s):  
F. Selles ◽  
C. A. Campbell ◽  
B. G. McConkey ◽  
S. A. Brandt ◽  
D. Messer
Keyword(s):  
Spatial Structure ◽  
Bulk Density ◽  
Multiple Regression ◽  
Geometric Mean ◽  
Transport Processes ◽  
Organic N ◽  
Soil N ◽  
Total Soil ◽  
Mineralizable N ◽  
Total Soil N

Producers and scientists are seeking more accurate methods for estimating the N-supplying power of soil at the field level. This has become more urgent as new management technologies, such as precision farming, gain popularity on the Canadian Prairies. We characterized the N status of the soil on an 18-ha site on which a new long-term alternative farming experiment was being initiated at Scott, Saskatchewan, by taking 160 cores in a systematic manner in June 1994. In these cores we determined: i) total soil N; and ii) the N-supplying power of the soil by determining mineralizable N by aerobic incubation at optimum temperature and moisture, and by extracting NH4–N with 2 M KCl at 100°C. Because the field had been fertilized shortly before sampling, residual fertilizer N severely affected the quality of determinations of N supplying power at the 0- to 7.5-cm depth. Consequently, we limited our investigation to the 7.5- to 15-cm depth. We also determined pH, bulk density, and particle size distribution. Using geostatistics, simple correlations, and multiple regression analyses, we demonstrated a close association between the biological and chemical measures of N-supplying power of the soil. Semivariograms revealed that the spatial structure of the variance of both variables was similar, with about 70% of the variance resulting from unidentified processes, and the rest explained by spatial structure. Field maps prepared with block-kriged estimates, revealed that these two measures of N-supplying power were similarly distributed throughout the landscape, and followed closely the spatial distribution of total soil N throughout most of the field. However, we identified two areas of the field where the two estimators of N-supplying power had a weak association with total soil N. Multiple regression and cluster analysis indicated that this disparity was a function of differences in soil pH, bulk density, and geometric mean diameter of soil particles, suggesting that soil erosion-transport processes may have altered the nature of organic N in areas of the field. The relationship between N mineralized during a 24-wk incubation and NH4–N extracted with hot KCl was not affected by these differences, suggesting that the biological and chemical procedures tested were accessing similar pools of soil N. We concluded that hot KCl NH4–N should prove useful for quantifying the N supplying power of soils. Key words: Geostatistics, estimation, kriging, spatial variability, mineralizable N

LONG-TERM TRENDS IN TOTAL SOIL N AS INFLUENCED BY CERTAIN MANAGEMENT PRACTICES

Soil Science ◽  
1977 ◽  
Vol 124 (2) ◽  
pp. 110-116 ◽  
Author(s):  
V. W. MEINTS ◽  
L. T. KURTZ ◽  
S. W. MELSTED ◽  
T. R. PECK
Keyword(s):  
Management Practices ◽  
Soil N ◽  
Total Soil ◽  
Long Term Trends ◽  
Total Soil N

Variations in natural enrichment of 15N in the profiles of some Australian pasture soils

Soil Research ◽  
1984 ◽  
Vol 22 (2) ◽  
pp. 155 ◽  
Author(s):  
SF Ledgard ◽  
JR Freney ◽  
JR Simpson
Keyword(s):  
Soil Depth ◽  
Trifolium Subterraneum ◽  
Parent Material ◽  
Organic N ◽  
Soil N ◽  
Total N ◽  
Total Soil ◽  
Lateral Variations ◽  
Total Soil N ◽  
Natural Enrichment

Variability in the natural enrichment of 15N in total nitrogen (N) and several N fractions was examined for profiles of pasture soils differing in parent material and period under Trifolium subterraneum. The natural enrichment of 15N in the total N of surface soils (0-5 cm) within a 400 km2 catchment ranged from 2.55 to 6.79�(expressed as �15N with respect to atmospheric N2). There was no relationship with parent material, period under T. subterraneum or concentration of total N in the soil. In one soil, lateral variations in �15N over a 12 m2 grid were within the range of 5.01 to 7.95�. The �15N of total soil N always increased with depth in the soil profiles. This was associated with an increase in the stable clay-sized humus fraction, which had a higher �15N than the less humified organic N in sand and silt-sized fractions. One soil was separated into four depth layers in which �15N in the inorganic N, mineralizable N, plant-extractable N and total soil N were determined. The first three parameters all had lower �15N values than the total soil N. The �15N of total N increased with soil depth, whereas there was no change with depth in the other three parameters.

Short-term nitrogen-15 recovery vs. long-term total soil N gains in conventional and alternative cropping systems

2002 ◽  
Vol 34 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Andrew W Kramer ◽  
Timothy A Doane ◽  
William R Horwath ◽  
Chris van Kessel
Keyword(s):  
Cropping Systems ◽  
Soil N ◽  
Short Term ◽  
Total Soil ◽  
Total Soil N

Comparison of rotations in which barley for grain follows woollypod vetch or forage barley

1987 ◽  
Vol 108 (3) ◽  
pp. 609-615 ◽  
Author(s):  
I. Papastylianou ◽  
Th. Samios
Keyword(s):  
Grain Yield ◽  
Dry Matter ◽  
Nitrogen Concentration ◽  
N Balance ◽  
Dry Matter Yield ◽  
Soil N ◽  
Fertilizer N ◽  
Total Soil ◽  
Using Data ◽  
Total Soil N

SummaryUsing data from rotation studies in which barley or woollypod vetch were included, both cut for hay and preceding barley for grain, it is shown that forage barley gave higher dry-matter yield than woollypod vetch (3·74 v. 2·92 t/ha per year). However, the latter gave feedingstuff of higher nitrogen concentration and yield (86 kg N/ha per year for vetch v. 55 kg N/ha per year for barley). Rainfall was an important factor in controlling the yield of the two forages and the comparison between them in different years and sites. Barley following woollypod vetch gave higher grain yield than when following forage barley (2·36 v. 1·91 t/ha). Rotation sequences which included woollypod vetch had higher output of nitrogen (N) than input of fertilizer N with a positive value of 44–60 kg N/ha per year. In rotations where forage barley was followed by barley for grain the N balance between output and input was 5–6 kg N/ha. Total soil N was similar in the different rotations at the end of a 7-year period.

Dynamics of nitrogen and dry-matter partitioning and accumulation in broccoli (Brassica oleracea var. italica) in relation to extractable soil inorganic nitrogen

1999 ◽  
Vol 79 (2) ◽  
pp. 277-286 ◽  
Author(s):  
P. A. Bowen ◽  
B. J. Zebarth ◽  
P. M. A. Toivonen
Keyword(s):  
Dry Matter ◽  
N Fertilization ◽  
N Fertilizer ◽  
Organic N ◽  
Soil N ◽  
Inorganic N ◽  
N Accumulation ◽  
Spring Planting ◽  
Extractable Soil ◽  
Soil Inorganic

The effects of six rates of N fertilization (0, 125, 250, 375, 500 and 625 kg N ha−1) on the dynamics of N utilization relative to extractable inorganic N in the soil profile were determined for broccoli in three growing seasons. The amount of pre-existing extractable inorganic N in the soil was lowest for the spring planting, followed by the early-summer then late-summer plantings. During the first 2 wk after transplanting, plant dry-matter (DM) and N accumulation rates were low, and because of the mineralization of soil organic N the extractable soil inorganic N increased over that added as fertilizer, especially in the top 30 cm. From 4 wk after transplanting until harvest, DM and N accumulation in the plants was rapid and corresponded to a rapid depletion of extractable inorganic N from the soil. At high N-fertilization rates, leaf and stem DM and N accumulations at harvest were similar among the three plantings. However, the rates of accumulation in the two summer plantings were higher before and lower after inflorescence initiation than those in the spring planting. Under N treatments of 0 and 125 kg ha−1, total N in leaf tissue and the rate of leaf DM accumulation decreased while inflorescences developed. There was little extractable inorganic soil-N during inflorescence development in plots receiving no N fertilizer, yet inflorescence dry weights and N contents were ≥50 and ≥30%, respectively, of the maxima achieved with N fertilization. These results indicate that substantial N is translocated from leaves to support broccoli inflorescence growth under conditions of low soil-N availability. Key words: N translocation, N fertilizer

Long-term dynamics of mycorrhizal root tips in a loblolly pine forest grown with free-air CO2enrichment and soil N fertilization for 6 years

2014 ◽  
Vol 20 (4) ◽  
pp. 1313-1326 ◽  
Author(s):  
Seth G. Pritchard ◽  
Benton N. Taylor ◽  
Emily R. Cooper ◽  
Katilyn V. Beidler ◽  
Allan E. Strand ◽  
...  
Keyword(s):  
Loblolly Pine ◽  
N Fertilization ◽  
Pine Forest ◽  
Soil N ◽  
Root Tips ◽  
Mycorrhizal Root ◽  
Free Air

Soil responses to topsoil replacement depth and organic amendments in wellsite reclamation

2005 ◽  
Vol 85 (2) ◽  
pp. 307-317 ◽  
Author(s):  
Francis J. Larney ◽  
Olalekan O. Akinremi ◽  
Reynald L. Lemke ◽  
Vasile E. Klaassen ◽  
H. Henry Janzen
Keyword(s):  
Soil Properties ◽  
Nitrate Nitrogen ◽  
Organic Amendments ◽  
Soil Surface ◽  
Triticum Aestivum L ◽  
Organic N ◽  
Medicago Sativa L ◽  
Soil Responses ◽  
Changes In Soil Properties

Changes in soil properties reflect the success or failure of reclamation practices on abandoned wellsites. We examined the effect on soil properties of four (0, 50, 100 and 150%) topsoil replacement depths (TRD) and five amendment treatments [compost, manure, wheat (Triticum aestivum L.) straw, alfalfa (Medicago sativa L.) hay, check] aimed at reclaiming three wellsites (Strathmore, Hesketh and Rosedale) in southcentral Alberta. TRD treatment differences were consistent across all wellsites, with 30 to 32% higher soil organic carbon (SOC) on the 150% TRD compared to the 0% TRD. Initially, the alfalfa treatment showed higher levels of nitrate-nitrogen (e.g., 26 mg kg-1 vs. 3 to 7 mg kg-1 for the other amendment treatments in the 15- to 30-cm depth at Strathmore in fall 1998), which was related to its rapid breakdown and mineralization of organic N. After 40 mo (June 1997-October 2000), the average amounts (n = 3 wellsites) of added C conserved near the soil surface were: compost (65 ±10% SE) > manure (45 ±16% SE) > alfalfa (28 ±11% SE) > straw (23 ± 6% SE). Our results show that organic amendments play an important role in improving soil properties related to long-term productivity of reclaimed wellsites, especially where topsoil is scarce or absent. Key words: Wellsite reclamation, topsoil depth, organic amendments, soil quality

scholarly journals Long-term warming and nitrogen fertilization affect C-, N- and P-acquiring hydrolase and oxidase activities in winter wheat monocropping soil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chuang Zhang ◽  
Wenxu Dong ◽  
Kiril Manevski ◽  
Wenpei Hu ◽  
Arbindra Timilsina ◽  
...  
Keyword(s):  
Agricultural Soils ◽  
C:N Ratio ◽  
Resource Limitation ◽  
N Fertilization ◽  
Organic N ◽  
Resource Limitations ◽  
The North ◽  
The Relationship ◽  
Enzyme Ratio

AbstractThe enzymatic activities and ratios are critical indicators for organic matter decomposition and provide potentially positive feedback to carbon (C) loss under global warming. For agricultural soils under climate change, the effect of long-term warming on the activities of oxidases and hydrolases targeting C, nitrogen (N) and phosphorus (P) and their ratios is unclear, as well as whether and to what extend the response is modulated by long-term fertilization. A 9-year field experiment in the North China Plain, including an untreated control, warming, N fertilization, and combined (WN) treatment plots, compared the factorial effect of warming and fertilization. Long-term warming interacted with fertilization to stimulate the highest activities of C, N, and P hydrolases. Activities of C and P hydrolase increased from 8 to 69% by N fertilization, 9 to 53% by warming, and 28 to 130% by WN treatment compared to control, whereas the activities of oxidase increased from 4 to 16% in the WN soils. Both the warming and the WN treatments significantly increased the enzymatic C:N ratio from 0.06 to 0.16 and the vector length from 0.04 to 0.12 compared to the control soil, indicating higher energy and resource limitation for the soil microorganisms. Compared to WN, the warming induced similar ratio of oxidase to C hydrolase, showing a comparable ability of different microbial communities to utilize lignin substrates. The relationship analyses showed mineralization of organic N to mediate the decomposition of lignin and enzyme ratio in the long-term warming soil, while N and P hydrolases cooperatively benefited to induce more oxidase productions in the soil subject to both warming and N fertilization. We conclude that coupled resource limitations induced microbial acclimation to long-term warming in the agricultural soils experiencing high N fertilizer inputs.

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