In situ studies of soil mineral N fluxes: Some comments on the applicability of the sequential soil coring method in arable soils

1996 ◽  
Vol 183 (2) ◽  
pp. 199-211 ◽  
Author(s):  
Roland Stenger ◽  
Eckart Priesack ◽  
Friedrich Beese
Keyword(s):  
Soil Mineral N ◽  
Soil Mineral ◽  
Arable Soils ◽  
Mineral N ◽  
In Situ Studies ◽  
N Fluxes

Methodology for studying fluxes of soil mineral-N in situ

1987 ◽  
Vol 19 (5) ◽  
pp. 521-530 ◽  
Author(s):  
R.J. Raison ◽  
M.J. Connell ◽  
P.K. Khanna
Keyword(s):  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N

Nutrient management in a Pinusradiata plantation after thinning: the effect of nitrogen fertilizer on soil nitrogen fluxes and tree growth

1995 ◽  
Vol 25 (10) ◽  
pp. 1673-1683 ◽  
Author(s):  
J.C. Carlyle
Keyword(s):  
N Uptake ◽  
Fertilizer Application ◽  
N Fertilizer ◽  
Soil Mineral N ◽  
Fertilizer N ◽  
Soil Mineral ◽  
Mineral N ◽  
N Fluxes ◽  
Highly Correlated ◽  
The Relationship

The influence of N fertilizer on soil mineral N fluxes, canopy development, and tree growth was studied in a thinned 11-year-old Pinusradiata D. Don plantation. Ammonium sulphate and single superphosphate were applied in an incomplete factorial design, but only the main effects of N application at 0 (control) or 200 kg N•ha−1 are considered here. Spring application of fertilizer increased the quantity of mineral N in the forest floor plus surface soil (0–0.30 m) from 1.2 to 194 kg•ha−1. Within 51 weeks this had fallen to 8.3 kg•ha−1, and after 89 weeks had returned to prefertilizer levels. In the unfertilized soil, rates of net mineralization were low with little seasonal variation. Nitrogen fertilizer increased N mineralization; over the 2 years of measurement fertilized and unfertilized soils mineralized 155 and 77 kg N•ha−1, respectively. There was no net immobilization of fertilizer N. There was no leaching of mineral N from the unfertilized soil whereas 149 kg N•ha−1 was leached below 0.30 m during the 2 years after fertilizer application. Nitrogen uptake increased from 71 kg•ha−1 in the control to 203 kg•ha−1 in the fertilized treatment. Fifty-one percent (103 kg•ha−1) of N uptake by trees in the fertilized treatment occurred within 20 weeks of fertilizer application. Fertilized trees took up 58% of the available N (N added as fertilizer plus N mineralized), while 42% was leached. Ammonium dominated the soil mineral N pool and mineral N fluxes, with nitrate generally accounting for less than 10% of mineral N in both fertilized and unfertilized soils. Leaching of mineral N from the fertilized soil (Nleach, kg•ha−1•week−1) was highly correlated (r2 = 0.92) with soil mineral N content (Nstart, kg•ha−1) and effective rainfall (rainfall minus evaporation, Reff, mm•week−1) according to the relationship Nleach = aNstart + bReff, while N uptake (kg•ha−1•week−1) was highly correlated (r2 = 0.91) with soil mineral N content and N mineralization (Nmin, kg•ha−1•week−1) according to the relationship Nuptake = aNstart + bNmin. Fertilizer increased needle N concentrations and content by 52 and 87%, respectively, after 58 weeks, and resulted in a 17% increase in leaf area index after 71 weeks. These differences were reflected by an increase in basal area increment of 23% during the 2 years since fertilizer application. The rapid uptake of N fertilizer was associated with storage in existing biomass. Uptake of fertilizer N should, therefore, increase with plantation biomass. Consequently, it should be possible to increase the uptake of N fertilizer, and minimize leaching, by applying fertilizer before, rather than after, thinning. Such a strategy may be particularly appropriate for soils that have a low capacity to retain applied N.

scholarly journals Nitrogen enrichment enhances the dominance of grasses over forbs in a temperate steppe ecosystem

2011 ◽  
Vol 8 (8) ◽  
pp. 2341-2350 ◽  
Author(s):  
L. Song ◽  
X. Bao ◽  
X. Liu ◽  
Y. Zhang ◽  
P. Christie ◽  
...  
Keyword(s):  
Species Richness ◽  
Aboveground Biomass ◽  
N Deposition ◽  
Soil Mineral N ◽  
N Addition ◽  
Soil Mineral ◽  
Temperate Steppe ◽  
Mineral N ◽  
N Concentration ◽  
Steppe Ecosystem

Abstract. Chinese grasslands are extensive natural ecosystems that comprise 40 % of the total land area of the country and are sensitive to N deposition. A field experiment with six N rates (0, 30, 60, 120, 240, and 480 kg N ha−1 yr−1) was conducted at Duolun, Inner Mongolia, during 2005 and 2010 to identify some effects of N addition on a temperate steppe ecosystem. The dominant plant species in the plots were divided into two categories, grasses and forbs, on the basis of species life forms. Enhanced N deposition, even as little as 30 kg N ha−1 yr−1 above ambient N deposition (16 kg N ha−1 yr−1), led to a decline in species richness. The cover of grasses increased with N addition rate but their species richness showed a weak change across N treatments. Both species richness and cover of forbs declined strongly with increasing N deposition as shown by linear regression analysis (p < 0.05). Increasing N deposition elevated aboveground production of grasses but lowered aboveground biomass of forbs. Plant N concentration, plant δ15N and soil mineral N increased with N addition, showing positive relationships between plant δ15N and N concentration, soil mineral N and/or applied N rate. The cessation of N application in the 480 kg N ha−1 yr−1 treatment in 2009 and 2010 led to a slight recovery of the forb species richness relative to total cover and aboveground biomass, coinciding with reduced plant N concentration and soil mineral N. The results show N deposition-induced changes in soil N transformations and plant N assimilation that are closely related to changes in species composition and biomass accumulation in this temperate steppe ecosystem.

Gross rates of soil N2O emission and uptake and denitrification gene abundance in temperate cropland agroforestry and monoculture systems

2021 ◽  
Author(s):  
Jie Luo ◽  
Lukas Beule ◽  
Guodong Shao ◽  
Edzo Veldkamp ◽  
Marife D. Corre
Keyword(s):  
Greenhouse Gas ◽  
Management Systems ◽  
Soil N ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Total N ◽  
Soil P ◽  
Gene Abundance ◽  
Denitrification Gene

&lt;p&gt;Monoculture croplands are considered as major sources of the greenhouse gas, nitrous oxide (N&lt;sub&gt;2&lt;/sub&gt;O). The conversion of monoculture croplands to agroforestry systems, e.g., integrating trees within croplands, is an essential climate-smart management system through extra C sequestration and can potentially mitigate N&lt;sub&gt;2&lt;/sub&gt;O emissions. So far, no study has systematically compared gross rates of N&lt;sub&gt;2&lt;/sub&gt;O emission and uptake between cropland agroforestry and monoculture. In this study, we used an in-situ &lt;sup&gt;15&lt;/sup&gt;N&lt;sub&gt;2&lt;/sub&gt;O pool dilution technique to simultaneously measure gross N&lt;sub&gt;2&lt;/sub&gt;O emission and uptake over two consecutive growing seasons (2018 - 2019) at three sites in Germany: two sites were on Phaeozem and Cambisol soils with each site having a pair of cropland agroforestry and monoculture systems, and an additional site with only monoculture on an Arenosol soil prone to high nitrate leaching. Our results showed that cropland agroforestry had lower gross N&lt;sub&gt;2&lt;/sub&gt;O emissions and higher gross N&lt;sub&gt;2&lt;/sub&gt;O uptake than in monoculture at the site with Phaeozem soil (P &amp;#8804; 0.018 &amp;#8211; 0.025) and did not differ in gross N&lt;sub&gt;2&lt;/sub&gt;O emissions and uptake with cropland monoculture at the site with Cambisol soil (P &amp;#8805; 0.36). Gross N&lt;sub&gt;2&lt;/sub&gt;O emissions were positively correlated with soil mineral N and heterotrophic respiration which, in turn, were correlated with soil temperature, and with water-filled pore space (WFPS) (r = 0.24 &amp;#8210; 0.54, P &lt; 0.01). Gross N&lt;sub&gt;2&lt;/sub&gt;O emissions were also negatively correlated with nosZ clade I gene abundance (involved in N&lt;sub&gt;2&lt;/sub&gt;O-to-N&lt;sub&gt;2&lt;/sub&gt; reduction, r = -0.20, P &lt; 0.05). These findings showed that across sites and management systems changes in gross N&lt;sub&gt;2&lt;/sub&gt;O emissions were driven by changes in substrate availability and aeration condition (i.e., soil mineral N, C availability, and WFPS), which also influenced denitrification gene abundance. The strong regression values between gross N&lt;sub&gt;2&lt;/sub&gt;O emissions and net N&lt;sub&gt;2&lt;/sub&gt;O emissions (R&lt;sup&gt;2 &lt;/sup&gt;&amp;#8805; 0.96, P &lt; 0.001) indicated that gross N&lt;sub&gt;2&lt;/sub&gt;O emissions largely drove net soil N&lt;sub&gt;2&lt;/sub&gt;O emissions. Across sites and management systems, annual soil gross N&lt;sub&gt;2&lt;/sub&gt;O emissions and uptake were controlled by clay contents which, in turn, correlated with indices of soil fertility (i.e., effective cation exchange capacity, total N, and C/N ratio) (Spearman rank&amp;#8217;s rho = -0.76 &amp;#8211; 0.86, P &amp;#8804; 0.05). The lower gross N&lt;sub&gt;2&lt;/sub&gt;O emissions from the agroforestry tree rows at two sites indicated the potential of agroforestry in reducing soil N&lt;sub&gt;2&lt;/sub&gt;O emissions, supporting the need for temperate cropland agroforestry to be considered in greenhouse gas mitigation policies.&lt;/p&gt;

Winter wheat yield and nitrous oxide emissions in response to cowpea-based green manure and nitrogen fertilization

2019 ◽  
Vol 56 (2) ◽  
pp. 239-254 ◽  
Author(s):  
Tanka P. Kandel ◽  
Prasanna H. Gowda ◽  
Brian K. Northup ◽  
Alexandre C. Rocateli
Keyword(s):  
Nitrous Oxide ◽  
Winter Wheat ◽  
Green Manure ◽  
Inorganic Nitrogen ◽  
Wheat Yield ◽  
Nitrous Oxide Emissions ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Winter Wheat Yield

AbstractThe aim of this study was to compare the effects of cowpea green manure and inorganic nitrogen (N) fertilizers on yields of winter wheat and soil emissions of nitrous oxide (N2O). The comparisons included cowpea grown solely as green manure where all biomass was terminated at maturity by tillage, summer fallow treatments with 90 kg N ha−1 as urea (90-N), and no fertilization (control) at planting of winter wheat. Fluxes of N2O were measured by closed chamber methods after soil incorporation of cowpea in autumn (October–November) and harvesting of winter wheat in summer (June–August). Growth and yields of winter wheat and N concentrations in grain and straw were also measured. Cowpea produced 9.5 Mg ha−1 shoot biomass with 253 kg N ha−1 at termination. Although soil moisture was favorable for denitrification after soil incorporation of cowpea biomass, low concentrations of soil mineral N restricted emissions of N2O from cowpea treatment. However, increased concentrations of soil mineral N and large rainfall-induced emissions were recorded from the cowpea treatment during summer. Growth of winter wheat, yield, and grain N concentrations were lowest in response to cowpea treatment and highest in 90-N treatment. In conclusion, late terminated cowpea may reduce yield of winter wheat and increase emissions of N2O outside of wheat growing seasons due to poor synchronization of N mineralization from cowpea biomass with N-demand of winter wheat.

Cutting management and alfalfa stand age effects on organically grown corn grain yield and soil N availability

2017 ◽  
Vol 34 (2) ◽  
pp. 144-154 ◽  
Author(s):  
Adria L. Fernandez ◽  
Karina P. Fabrizzi ◽  
Nicole E. Tautges ◽  
John A. Lamb ◽  
Craig C. Sheaffer
Keyword(s):  
The Other ◽  
Stand Age ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
No Removal ◽  
Soil C ◽  
Biomass Removal ◽  
Potentially Mineralizable N ◽  
Corn Grain

AbstractAlfalfa is recommended as a rotational crop in corn production, due to its ability to contribute to soil nitrogen (N) and carbon (C) stocks through atmospheric N2fixation and above- and belowground biomass production. However, there is little information on how alfalfa management practices affect contributions to soil and subsequent corn crop yields, and research has not been targeted to organic systems. A study was conducted to determine the effects of alfalfa stand age, cutting frequency and biomass removal on soil C and N status and corn yields at three organically managed Minnesota locations. In one experiment, five cutting treatments were applied in nine environments: two, three and four cuts with biomass removal; three cuts with biomass remaining in place; and a no-cut control. In the other experiment, corn was planted following 1-, 2-, 3- or 4-year-old alfalfa stands and a no-alfalfa control. Yield was measured in the subsequent corn crop. In the cutting experiment, the two- and three-cut treatments with biomass removal reduced soil mineral N by 12.6 and 11.5%, respectively, compared with the control. Potentially mineralizable N (PMN) was not generally affected by cutting treatments. The three-cut no-removal increased potentially mineralizable C by 17% compared with the other treatments, but lowered soil total C in two environments, suggesting a priming effect in which addition of alfalfa biomass stimulated microbial mineralization of native soil C. Although both yields and soil mineral N tended to be higher in treatments where biomass remained in place, this advantage was small and inconsistent, indicating that farmers need not forgo hay harvest to obtain the rotational benefits of an alfalfa stand. The lack of overall correlation between corn grain yields and mineral and potentially mineralizable N suggests that alfalfa N contribution was not the driver of the yield increase in the no-removal treatments. Alfalfa stand age had inconsistent effects on fall-incorporated N and soil N and C parameters. Beyond the first year, increased alfalfa stand age did not increase soil mineral N or PMN. However, corn yield increased following older stands. Yields were 29, 77 and 90% higher following first-, second- and third-year alfalfa stands than the no-alfalfa control, respectively. This indicates that alfalfa may benefit succeeding corn through mechanisms other than N contribution, potentially including P solubilization and weed suppression. These effects have been less studied than N credits, but are of high value in organic cropping systems.

Computer simulation of changes in soil mineral nitrogen and crop nitrogen during autumn, winter and spring

1987 ◽  
Vol 109 (1) ◽  
pp. 141-157 ◽  
Author(s):  
T. M. Addiscott ◽  
A. P. Whitmore
Keyword(s):  
Soil Temperature ◽  
Dry Matter ◽  
N Uptake ◽  
Sowing Date ◽  
Mineralization Rate ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Crop N Uptake

summaryThe computer model described simulates changes in soil mineral nitrogen and crop uptake of nitrogen by computing on a daily basis the amounts of N leached, mineralized, nitrified and taken up by the crop. Denitrification is not included at present. The leaching submodel divides the soil into layers, each of which contains mobile and immobile water. It needs points from the soil moisture characteristic, measured directly or derived from soil survey data; it also needs daily rainfall and evaporation. The mineralization and nitrification submodel assumes pseudo-zero order kinetics and depends on the net mineralization rate in the topsoil and the daily soil temperature and moisture content, the latter being computed in the leaching submodel. The crop N uptake and dry-matter production submodel is a simple function driven by degree days of soil temperature and needs in addition only the sowing date and the date the soil returns to field capacity, the latter again being computed in the leaching submodel. A sensitivity analysis was made, showing the effects of 30% changes in the input variables on the simulated amounts of soil mineral N and crop N present in spring when decisions on N fertilizer rates have to be made. Soil mineral N was influenced most by changes in rainfall, soil water content, mineralization rate and soil temperature, whilst crop N was affected most by changes in soil temperature, rainfall and sowing date. The model has so far been applied only to winter wheat growing through autumn, winter and spring but it should be adaptable to other crops and to a full season.The model was validated by comparing its simulations with measurements of soil mineral N, dry matter and the amounts of N taken up by winter wheat in experiments made at seven sites during 5 years. The simulations were assessed graphically and with the aid of several statistical summaries of the goodness of fit. The agreement was generally very good; over all years 72% of all simulations of soil mineral N to 90 cm depth were within 20 kg N/ha of the soil measurements; also 78% of the simulations of crop nitrogen uptake were within 15 kg N/ha and 63% of the simulated yields of dry matter were within 25 g/m2 of the amounts measured. All correlation coefficients were large, positive, and highly significant, and on average no statistically significant differences were found between simulation and measurement either for soil mineral N or for crop N uptake.

Sign in / Sign up

Export Citation Format

Share Document