scholarly journals PLANT DIVERSITY, CO2, AND N INFLUENCE INORGANIC AND ORGANIC N LEACHING IN GRASSLANDS

Ecology ◽  
2007 ◽  
Vol 88 (2) ◽  
pp. 490-500 ◽  
Author(s):  
Feike A. Dijkstra ◽  
Jason B. West ◽  
Sarah E. Hobbie ◽  
Peter B. Reich ◽  
Jared Trost
2016 ◽  
Vol 131 (3) ◽  
pp. 339-353 ◽  
Author(s):  
Sophia Leimer ◽  
Yvonne Oelmann ◽  
Nico Eisenhauer ◽  
Alexandru Milcu ◽  
Christiane Roscher ◽  
...  

Author(s):  
Subin Kalu ◽  
Gboyega Nathaniel Oyekoya ◽  
Per Ambus ◽  
Priit Tammeorg ◽  
Asko Simojoki ◽  
...  

AbstractA 15N tracing pot experiment was conducted using two types of wood-based biochars: a regular biochar and a Kon-Tiki-produced nutrient-enriched biochar, at two application rates (1% and 5% (w/w)), in addition to a fertilizer only and a control treatment. Ryegrass was sown in pots, all of which except controls received 15N-labelled fertilizer as either 15NH4NO3 or NH415NO3. We quantified the effect of biochar application on soil N2O emissions, as well as the fate of fertilizer-derived ammonium (NH4+) and nitrate (NO3−) in terms of their leaching from the soil, uptake into plant biomass, and recovery in the soil. We found that application of biochars reduced soil mineral N leaching and N2O emissions. Similarly, the higher biochar application rate of 5% significantly increased aboveground ryegrass biomass yield. However, no differences in N2O emissions and ryegrass biomass yields were observed between regular and nutrient-enriched biochar treatments, although mineral N leaching tended to be lower in the nutrient-enriched biochar treatment than in the regular biochar treatment. The 15N analysis revealed that biochar application increased the plant uptake of added nitrate, but reduced the plant uptake of added ammonium compared to the fertilizer only treatment. Thus, the uptake of total N derived from added NH4NO3 fertilizer was not affected by the biochar addition, and cannot explain the increase in plant biomass in biochar treatments. Instead, the increased plant biomass at the higher biochar application rate was attributed to the enhanced uptake of N derived from soil. This suggests that the interactions between biochar and native soil organic N may be important determinants of the availability of soil N to plant growth.


2021 ◽  
Author(s):  
Robert Reuter ◽  
Olga Ferlian ◽  
Mika Tarkka ◽  
Nico Eisenhauer ◽  
Karin Pritsch ◽  
...  

Abstract Mycorrhizal fungi play an important role for the nitrogen (N) supply of trees. The influence of different mycorrhizal types on N acquisition in tree-tree interactions is, however, not well understood, particularly with regard to the competition for growth-limiting N. We studied the effect of competition between temperate forest tree species on their inorganic and organic N acquisition in relation to their mycorrhizal type (i.e., arbuscular mycorrhiza or ectomycorrhiza). In a field experiment, we quantified net N uptake capacity from inorganic and organic N sources using 15N/13C stable isotopes for arbuscular mycorrhizal tree species (i.e., Acer pseudoplatanus L., Fraxinus excelsior L., and Prunus avium L.) as well as ectomycorrhizal tree species (i.e., Carpinus betulus L., Fagus sylvatica L., and Tilia platyphyllos Scop.). All species were grown in intra- and interspecific competition (i.e., monoculture or mixture). Our results showed that N sources were not used complementarily depending on a species´ mycorrhizal association, but their uptake rather depended on the competitor indicating species-specific effects. Generally, ammonium was preferred over glutamine and glutamine over nitrate. In conclusion, our findings suggest that inorganic and organic N acquisition of the studied temperate tree species is less regulated by mycorrhizal association, but rather by the availability of specific N sources in the soil as well as the competitive environment of different tree species.


Toxins ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 724
Author(s):  
Siyi Tao ◽  
Suqin Wang ◽  
Lirong Song ◽  
Nanqin Gan

Cyanotoxins are the underlying cause of the threat that globally pervasive Cyanobacteria Harmful algal blooms (CyanoHABs) pose to humans. Major attention has been focused on the cyanobacterial hepatotoxin microcystins (MCs); however, there is a dearth of studies on cyanobacterial neurotoxin anatoxins. In this study, we explored how an anatoxin-producing Cuspidothrix issatschenkoi strain responded to culture with inorganic and organic nitrogen sources in terms of growth and anatoxins production. The results of our study revealed that ʟ- alanine could greatly boost cell growth, and was associated with the highest cell productivity, while urea significantly stimulated anatoxin production with the maximum anatoxin yield reaching 25.86 μg/mg dry weight, which was 1.56-fold higher than that in the control group (BG11). To further understand whether the carbon/nitrogen balance in C. issatschenkoi would affect anatoxin production, we explored growth and toxin production in response to different carbon/nitrogen ratios (C/N). Anatoxin production was mildly promoted when the C/N ratio was within low range, and significantly inhibited when the C/N ratio was within high range, showing approximately a three-fold difference. Furthermore, the transcriptional profile revealed that anaC gene expression was significantly up-regulated over 2–24 h when the C/N ratio was increased, and was significantly down-regulated after 96 h. Overall, our results further enriched the evidence that urea can stimulate cyanotoxin production, and ʟ-alanine could boost C. issatschenkoi proliferation, thus providing information for better management of aquatic systems. Moreover, by focusing on the intracellular C/N metabolic balance, this study explained the anatoxin production dynamics in C. issatschenkoi in response to different N sources.


Geoderma ◽  
2004 ◽  
Vol 121 (3-4) ◽  
pp. 291-306 ◽  
Author(s):  
Ángeles Prieto-Fernández ◽  
Modesto Carballas ◽  
Tarsy Carballas

Author(s):  
E. I. Butler ◽  
Susan Knox ◽  
M. I. Liddicoat

The seasonal variations of dissolved inorganic and organic N and P in the waters of the English Channel during an 11-year study are discussed. The N results show that as NO3 is utilized by phytoplankton there is an increase in the concentration of the dissolved organic N fraction and there are always significant amounts of dissolved N in some form in the water.


2011 ◽  
Vol 51 (5) ◽  
pp. 416 ◽  
Author(s):  
C. J. Hoogendoorn ◽  
K. Betteridge ◽  
S. F. Ledgard ◽  
D. A. Costall ◽  
Z. A. Park ◽  
...  

A replicated grazing study measuring nitrogen (N) leaching from cattle-, sheep- and deer-grazed pastures was conducted to investigate the impact of different animal species on N leaching in the Lake Taupo catchment in New Zealand. Leaching losses of nitrate N from intensively grazed pastures on a highly porous pumice soil in the catchment averaged 37, 26 and 25 kg N/ha.year for cattle-, sheep- and deer-grazed areas, respectively, over the 3-year study and were not significantly different (P > 0.05). Leaching losses of ammonium N were much lower (3 kg N/ha.year for all three species of grazer; P > 0.05). Amounts of dissolved organic N leached were significantly higher than that of mineral N (nitrate N + ammonium N), and over the 3-year study averaged 44, 43 and 39 kg N/ha.year for cattle-, sheep- and deer-grazed areas, respectively (P > 0.05). On a stock unit equivalence basis (1 stock unit is equivalent to 550 kg DM consumed/year), cattle-grazed areas leached significantly more mineral N than sheep- or deer-grazed areas (5.5, 2.9 and 3.4 g mineral N leached/24 h grazing by 1 stock unit, for cattle, sheep and deer, respectively) (P < 0.001). Likewise, based on the amount of N apparently consumed (estimated by difference in mass of herbage N pre- and post-grazing), cattle-grazed pastures leached more mineral N than sheep- or deer-grazed pastures (123, 75 and 75 g mineral N/kg N apparently consumed for cattle, sheep and deer, respectively) (P < 0.01). This study gives valuable information on mineral N leaching in a high-rainfall environment on this free-draining pumice soil, and provides new data to assist in developing strategies to mitigate mineral N leaching losses from grazed pastures using different animal species.


Nitrogen ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 41-61
Author(s):  
Nouraya Akkal-Corfini ◽  
Paul Robin ◽  
Safya Menasseri-Aubry ◽  
Michael S. Corson ◽  
Jean Paul Sévère ◽  
...  

The goal of the European Nitrate Directive 91/676/CEE is to mitigate or prevent water pollution associated with the nitrogen (N) cascade. Vegetable crops have a high risk of nitrate leaching during autumn and winter. Information about the fate of N from artichoke (Cynara cardunculus L. var. scolymus (L.)) residues is reviewed and then supplemented with a three-year study with 15N-labelled residues in an artichoke-cauliflower (Brassica oleracea L. cv. botrytis) rotation in six lysimeters. After three years, 6% of N in artichoke residues was leached, 8% was exported by crops, while 86% remained in the lysimeter. Summed over the rotation, 16% of artichoke-residue N was absorbed by artichoke and 14% by cauliflower. Total aboveground N uptake by all crops during the entire rotation ranged from 370 to 534 kg N ha−1, of which 207–311 kg N ha−1 returned to the soil as residues. Increasing N-recycling efficiency and reducing the risk of N leaching while conserving crop productivity requires capturing N mineralized from soil organic N. Cauliflower performs this capture effectively during the drainage period. A break crop should be introduced after the first and second harvests of artichoke to further synchronize N mineralization and uptake and reduce leaching risk during the rotation.


Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 463 ◽  
Author(s):  
Carlo Nicoletto ◽  
Luisa Dalla Costa ◽  
Paolo Sambo ◽  
Giampaolo Zanin

Understanding nitrogen use efficiency (NUE) of crops plays an important role in achieving sustainable production. Intensive agriculture has adversely affected social and environmental issues worldwide over the past few decades. Anaerobic digested residues from the distillery industry (DADRs) can be used in agriculture, thereby recycling valuable organic materials that can supply organic N. An experiment using DADRs in horticulture was conducted to evaluate the performance of different treatments on yield and NUE. The experiment was conducted for five years, growing lettuce, cauliflower, chicory, potato, Swiss chard, catalogna chicory, tomato, pepper, and melon in two different succession schemes. Five fertilization treatments were designed, including a mineral fertilization control, in which nitrogen (N) was supplied according to standard recommendations in the area. The other treatments were an unfertilized control and three treatments in which 50%, 75%, and 100% of the N were supplied by DADRs and the remaining with common chemical fertilizer. Major findings were: (1) Spring–summer crops showed the lowest N-uptake and N recovery, during this period high chemical fertilization can cause environmental problems such as N leaching, and fertilization with 100% DADRs is a viable alternative; (2) fall–winter crops can be fertilized by combining 50% mineral N and 50% organic N, supplying the nutrients required by the crops during the growing cycle.


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