Response of soil mineral nitrogen to total nitrogen and land-use in a long-term study of wheat pasture rotations

1988 ◽  
Vol 28 (4) ◽  
pp. 525
Author(s):  
AC Taylor ◽  
WJ Lill
Keyword(s):  
Land Use ◽  
Wagga Wagga ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Term Study ◽  
Mineral N ◽  
Total N ◽  
Long Term Study ◽  
Wheat Pasture

All 6 treatments of a long-term wheat-pasture rotation experiment were soil sampled after a cultivated fallow close to sowing at Wagga Wagga. Analyses of the nitrogen (N) data show that total N (0-1 5 cm) could be used as a predictor of mineral N in the profile at sowing. Mineral N levels were expressed as a percentage of total N and reported as a mineralisation index. This index increased after a period of clover and was considerably higher for the first crop after pasture than for subsequent crops. The mineralisation index also increased as the pasture intensity (years pasture/total years) increased from 0.33 to 0.67. Total N alone accounted for no more than 20% of the variation in mineral N at sowing. The variance accounted for increased to 49.9 and 53.7% respectively when pasture frequency and crop number after pasture were included in the models.

Organic amendment effects on tuber yield, plant N uptake and soil mineral N under organic potato production

2008 ◽  
Vol 23 (03) ◽  
pp. 250-259 ◽  
Author(s):  
Derek H. Lynch ◽  
Zhiming Zheng ◽  
Bernie J. Zebarth ◽  
Ralph C. Martin
Keyword(s):  
N Uptake ◽  
N Availability ◽  
Residual Soil ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Total N ◽  
Available N ◽  
Organic Potato ◽  
Certified Organic

AbstractThe market for certified organic potatoes in Canada is growing rapidly, but the productivity and dynamics of soil N under commercial organic potato systems remain largely unknown. This study examined, at two sites in Atlantic Canada (Winslow, PEI, and Brookside, NS), the impacts of organic amendments on Shepody potato yield, quality and soil mineral nitrogen dynamics under organic management. Treatments included a commercial hog manure–sawdust compost (CP) and pelletized poultry manure (NW) applied at 300 and 600 kg total N ha−1, plus an un-amended control (CT). Wireworm damage reduced plant stands at Brookside in 2003 and those results are not presented. Relatively high tuber yields (~30 Mg ha−1) and crop N uptake (112 kg N ha−1) were achieved for un-amended soil in those site-years (Winslow 2003 and 2004) when soil moisture was non-limiting. Compost resulted in higher total yields than CT in one of three site-years. Apparent recovery of N from CP was negligible; therefore CP yield benefits were attributed to factors other than N availability. At Winslow, NW300, but not NW600, significantly increased total and marketable yields by an average of 5.8 and 7.0 Mg ha−1. Plant available N averaged 39 and 33% for NW300 and NW600, respectively. Soil (0–30 cm) NO3−-N at harvest was low (<25 kg N ha−1) for CT and CP, but increased substantially both in season and at harvest (61–141 kg N ha−1) when NW was applied. Most leaching losses of NO3−-N occur between seasons and excessive levels of residual soil NO3-N at harvest, as obtained for NW600, must be avoided. Given current premiums for certified organic potatoes, improving yields through application of amendments supplying moderate rates of N or organic matter appears warranted.

Effects of long-term straw management and fertilizer nitrogen additions on soil nitrogen supply and crop yields at two sites in eastern England

2002 ◽  
Vol 139 (2) ◽  
pp. 115-127 ◽  
Author(s):  
MARTYN SILGRAM ◽  
BRIAN J. CHAMBERS
Keyword(s):  
Soil Nitrogen ◽  
Nitrogen Supply ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Plough Layer ◽  
N Rates ◽  
Soil Nitrogen Supply

The effects of straw incorporation (early and late cultivation) and straw burning were contrasted in a split-plot study examining the impact of long-term straw residue management, and six fertilizer nitrogen (N) rates on soil mineral nitrogen, crop fertilizer N requirements and nitrate leaching losses. The experiments ran from 1984 to 1997 on light-textured soils at ADAS Gleadthorpe (Nottinghamshire, UK) and Morley Research Centre (Norfolk, UK).Soil incorporation of the straw residues returned an estimated 633 kg N/ha at Gleadthorpe and 429 kg N/ha at Morley on the treatment receiving 150 kg/ha per year fertilizer N since 1984. Straw disposal method had no consistent effect on grain and straw yields, crop N uptake, or optimal fertilizer N rates. In every year there was a positive response (P<0·001) to fertilizer N in straw/grain yields, N contents and crop N offtakes at both sites. Nitrate leaching losses were slightly reduced by less than 10 kg N/ha where straw residues had been incorporated, while fertilizer N additions increased nitrate leached at both sites.At both sites there was a consistent effect (P<0·001) of straw disposal method on autumn soil mineral N, with values following the pattern burn>early incorporate>late plough. The incorporation of straw residues induced temporary N immobilization compared with the treatment where straw was burnt, while the earlier timing of tillage on the incorporate treatment resulted in slightly more mineral N compared with the later ploughed treatment. Fertilizer N rate increased (P<0·001) soil mineral nitrogen at both sites. At Morley, there was more organic carbon in the plough layer where straw had been incorporated (mean 1·09 g/100 g) rather than burnt (mean 0·89 g/100 g), and a strong positive relationship between organic carbon and fertilizer N rate (r2=93·2%, P<0·01). There was a detectable effect of fertilizer N on readily mineralizable N in the plough layer at both Gleadthorpe (P<0·001) and Morley (P<0·05). At Morley, there was a consistent trend (P=0·06) for readily mineralizable N to be higher where straw had been incorporated rather than burnt, indicating that ploughing-in residues may contribute to soil nitrogen supply over the longer term.

Orthoptera community shifts in response to land-use and climate change – Lessons from a long-term study across different grassland habitats

2019 ◽  
Vol 236 ◽  
pp. 315-323 ◽  
Author(s):  
Franz Löffler ◽  
Dominik Poniatowski ◽  
Thomas Fartmann
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Term Study ◽  
Long Term Study ◽  
Community Shifts ◽  
Grassland Habitats

The source of mineral nitrogen for cereals in south-eastern Australia

1998 ◽  
Vol 49 (3) ◽  
pp. 511 ◽  
Author(s):  
J. F. Angus ◽  
A. F. van Herwaarden ◽  
D. P. Heenan ◽  
R. A. Fischer ◽  
G. N. Howe
Keyword(s):  
Root Zone ◽  
Growing Season ◽  
Crop Growth ◽  
Mineral Nitrogen ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Total N ◽  
Eastern Australia ◽  
Net Mineralisation

The relative importance of soil mineral nitrogen (N) available at the time of sowing ormineralised during the growing season was investigated for 6 crops of dryland wheat. The soil mineral N in the root-zone was sampled at sowing and maturity and the rate of net mineralisation in the top 10 cm was estimated by sequential sampling throughout the growing season, using an in situ method. Mineralisation during crop growth was modelled in relation to total soil N, ambient temperature, andsoil water content. Mineral N accumulated before sowing varied by a factor of 3 between the sites (from 67 to 195 kgN/ha), while the net mineralisation during crop growth varied by a factor of 2 (from 43 to 99 kgN/ha). The model indicated that 0·092% of total N was mineralised per day when temperature and water were not limiting, with rates decreasing for lower temperatures and soil water contents. When tested with independent data, the model predicted the mineralisation rate of soil growing continuous wheat crops but underestimated mineralisation of soil in a clover-wheat rotation. For crops yielding <3 t/ha, the supply of N was mostly from mineralisation during crop growth and the contribution from mineral N accumulated before sowing was relatively small. For crops yielding >4 t/ha, thesupply of N was mostly from N present in the soil at the time of sowing. The implication is that for crops to achieve their water-limited yield, they must be supplied with an amount of N greater than can be expected from mineralisation during the growing season, either from fertiliser or from mineral N accumulated earlier.

Repeated Botox Injections Deemed Safe in Long-Term Study

2005 ◽  
Vol 36 (1) ◽  
pp. 2
Author(s):  
BETSY BATES
Keyword(s):  
Term Study ◽  
Long Term Study

Long-Term Study Proves Permanent Filler Safety

2010 ◽  
Vol 41 (4) ◽  
pp. 23
Author(s):  
BRUCE JANCIN
Keyword(s):  
Term Study ◽  
Long Term Study ◽  
Permanent Filler

Quinapril for Sclerosis Failed in Long-Term Study

2007 ◽  
Vol 38 (6) ◽  
pp. 14
Author(s):  
DAMIAN MCNAMARA
Keyword(s):  
Term Study ◽  
Long Term Study

High-Dose Etanercept Found To Be Safe in Long-Term Study

2007 ◽  
Vol 38 (10) ◽  
pp. 45
Author(s):  
MARY ANN MOON
Keyword(s):  
High Dose ◽  
Term Study ◽  
Long Term Study
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