Vascular plant removal effects on biological N fixation vary across a boreal forest island gradient

Ecology ◽  
2010 ◽  
Vol 91 (6) ◽  
pp. 1704-1714 ◽  
Author(s):  
Michael J. Gundale ◽  
David A. Wardle ◽  
Marie-Charlotte Nilsson
Keyword(s):  
Boreal Forest ◽  
Vascular Plant ◽  
N Fixation ◽  
Biological N Fixation ◽  
Plant Removal ◽  
Forest Island

scholarly journals Plant and soil nitrogen in oligotrophic boreal forest habitats with varying moss depths: does exclusion of large grazers matter?

Oecologia ◽  
2021 ◽  
Author(s):  
Maria Väisänen ◽  
Maria Tuomi ◽  
Hannah Bailey ◽  
Jeffrey M. Welker
Keyword(s):  
Boreal Forest ◽  
Vascular Plant ◽  
Soil N ◽  
Inorganic N ◽  
N Dynamics ◽  
N Content ◽  
Feather Moss ◽  
Foliar N ◽  
Plant Soil ◽  
Plant Soil Interactions

AbstractThe boreal forest consists of drier sunlit and moister-shaded habitats with varying moss abundance. Mosses control vascular plant–soil interactions, yet they all can also be altered by grazers. We determined how 2 decades of reindeer (Rangifer tarandus) exclusion affect feather moss (Pleurozium schreberi) depth, and the accompanying soil N dynamics (total and dissolvable inorganic N, δ15N), plant foliar N, and stable isotopes (δ15N, δ13C) in two contrasting habitats of an oligotrophic Scots pine forest. The study species were pine seedling (Pinus sylvestris L.), bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.), and feather moss. Moss carpet was deeper in shaded than sunlit habitats and increased with grazer exclusion. Humus N content increased in the shade as did humus δ15N, which also increased due to exclusion in the sunlit habitats. Exclusion increased inorganic N concentration in the mineral soil. These soil responses were correlated with moss depth. Foliar chemistry varied due to habitat depending on species identity. Pine seedlings showed higher foliar N content and lower foliar δ15N in the shaded than in the sunlit habitats, while bilberry had both higher foliar N and δ15N in the shade. Thus, foliar δ15N values of co-existing species diverged in the shade indicating enhanced N partitioning. We conclude that despite strong grazing-induced shifts in mosses and subtler shifts in soil N, the N dynamics of vascular vegetation remain unchanged. These indicate that plant–soil interactions are resistant to shifts in grazing intensity, a pattern that appears to be common across boreal oligotrophic forests.

Seed size influences the promoting activity of rhizobia on plant growth, nodulation and N fixation in lima bean

2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Claudyanne do Nascimento Costa ◽  
Jadson Emanuel Lopes Antunes ◽  
João Pedro Alves de Aquino ◽  
Ingrid Sthephanie da Costa Silva ◽  
Angela Celis de Almeida Lopes ◽  
...  
Keyword(s):  
Plant Growth ◽  
Seed Size ◽  
Reference Strain ◽  
Dry Weight ◽  
Lima Bean ◽  
N Fixation ◽  
Nodule Number ◽  
Root Dry Weight ◽  
Biological N Fixation

ABSTRACT: This study evaluated the activity of rhizobia isolates inoculated in large (18 mm) and small (11 mm) seeds on lima bean growth, nodulation and N fixation. Selected rhizobia isolates were compared with a reference strain CIAT899 and two controls without inoculation. Large seeds contributed for highest plant growth, nodulation and N fixation than small seeds. The isolates UFPI-59, UFPI-18 and UFPI-38 promoted the highest values of shoot and root dry weight, respectively. The isolates UFPI-32 promoted the highest values of nodule number, while UFPI-59 promoted the highest values of nodule dry weight. The isolates UFPI-38 and UFPI-59 promoted the highest accumulation of N. This study showed that seed size really influences lima bean growth, nodulation and BNF. Considering rhizobia isolates, UFPI-59, UFPI-38, and UFPI-18 contributed for plant growth, promoted better nodulation and effectiveness on biological N fixation.

scholarly journals SYMBIOTIC EFFECTIVENESS AND COMPETITIVENESS OF CALOPO RHIZOBIAL ISOLATES IN AN ARGISSOLO VERMELHO-AMARELO UNDER THREE VEGETATION COVERS IN THE DRY FOREST ZONE OF PERNAMBUCO

2015 ◽  
Vol 39 (2) ◽  
pp. 367-376 ◽  
Author(s):  
Altanys Silva Calheiros ◽  
Mario de Andrade Lira Junior ◽  
Mércia Virgínia Ferreira Santos ◽  
Maria do Carmo Catanho Pereira Lyra
Keyword(s):  
Dry Mass ◽  
Dry Forest ◽  
N Fixation ◽  
Forage Legumes ◽  
Forest Zone ◽  
Biological N Fixation ◽  
Pasture Degradation ◽  
Calopogonium Mucunoides ◽  
N Rates ◽  
Rhizobial Isolates

Biological N fixation in forage legumes is an important alternative to reduce pasture degradation, and is strongly influenced by the inoculant symbiotic capability. This paper evaluates the effectiveness of Calopo (Calopogonium mucunoides) rhizobial isolated from soil under three vegetation covers of an Argissolo Vermelho-Amarelo of the Dry Forest Zone of Pernambuco. An experiment was conducted evaluating 25 isolates, aside from 5 uninoculated controls with 0; 309; 60; 90 and 120 kg ha-1 N, and a treatment inoculated with the SEMIA 6152 strain. The first cut was performed 45 days after inoculation and a second and third cut after 45-day-intervals. Shoot N content was quantified at all cuts. Shoot dry mass was affected by N rates at all cuts. Shoot dry mass increased from the first to the second cut in inoculated plants. There was no difference between rhizobial isolates from the different plant covers for any of the variables. Most variables were significantly and positively correlated.

scholarly journals Residual effect of clover-rich leys on soil nitrogen and successive grain crops

2008 ◽  
Vol 17 (1) ◽  
pp. 73 ◽  
Author(s):  
A. NYKÄNEN ◽  
A. GRANSTEDT ◽  
L. JAUHIAINEN
Keyword(s):  
Field Experiments ◽  
Clayey Soil ◽  
N Uptake ◽  
Residual Effect ◽  
Red Clover ◽  
N Leaching ◽  
N Fixation ◽  
Mineral N ◽  
Total N ◽  
Biological N Fixation

Legume-based leys form the basis for crop rotations in organic farming as they fix nitrogen (N) from the atmosphere for the succeeding crops. The age, yield, C:N, biological N fixation (BNF) and total N of red clover-grass leys were studied for their influence on yields, N uptake and N use efficiency (NUE) of the two sequential cereal crops planted after the leys. Mineral N in deeper soil (30-90 cm) was measured to determine N leaching risk. Altogether, four field experiments were carried out in 1994-1998 at two sites. The age of the ley had no significant effect on the yields and N uptake of the two subsequent cereals. Surprisingly, the residual effect of the leys was negligible, at 0–20 kg N ha-1yr-1. On the other hand, the yield and C:N of previous red clover-grass leys, as well as BNF-N and total-N incorporated into the soil influenced subsequent cereals. NUEs of cereals after ley incorporation were rather high, varying from 30% to 80%. This might indicate that other factors, such as competition from weeds, prevented maximal growth of cereals. The mineral N content deeper in the soil was mostly below 10 kg ha-1 in the sandy soil of Juva, but was 5-25 kg ha-1 in clayey soil of Mietoinen.;

Tillage effects on N2O emission from soils under corn and soybeans in Eastern Canada

2008 ◽  
Vol 88 (2) ◽  
pp. 153-161 ◽  
Author(s):  
E G Gregorich ◽  
P. Rochette ◽  
P. St-Georges ◽  
U F McKim ◽  
C. Chan
Keyword(s):  
Nitrous Oxide ◽  
Agricultural Soils ◽  
N2o Emission ◽  
N Fixation ◽  
Eastern Canada ◽  
N Losses ◽  
Biological N Fixation ◽  
No Till ◽  
Tillage System ◽  
Glycine Max L

The ways in which agricultural soils are managed influence the production and emission of nitrous oxide (N2O). A field study was undertaken in 2003, 2004, and 2005 to quantify and evaluate N2O emission from tilled and no-till soils under corn (Zea maysL.) and soybeans (Glycine max L. Merr) in Ontario. Overall, N2O emission was lowest in 2003, the driest and coolest of the 3 yr. In 2004, the significantly larger annual N2O emission from no-till soils and soils under corn was attributed to an episode of very high N2O emission following the application of fertilizer during a period of wet weather. That the N loss by N2O emission occurred only in no-till soils and was large and long-lasting (~4 wk) confirms the strong effect that management has in reducing fertilizer N losses. In 2005, tilled soils had significantly larger N2O emission than no-till soils, most of which was emitted before the end of June. Because the tilled soils were better aerated , nitrification was likely the primary process contributing to the larger emission. Relatively low N2O emission from soybeans suggests biological N fixation does not appear to contribute substantially to the annual N2O emission. Further study of methods to reduce N2O emission in agricultural systems should focus on improving N use efficiency within a particular tillage system rather than looking to differences between tillage systems. Key words: Tillage, corn, soybeans, nitrogen, nitrous oxide, biogenic gas emission, nitrification, denitrification, fertilization

scholarly journals Accumulation and Distribution of Fertilizer Nitrogen and Nodule-Fixed Nitrogen in Soybeans with Dual Root Systems

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 397 ◽  
Author(s):  
Rui Zhang ◽  
Cong Wang ◽  
Wenzhi Teng ◽  
Jing Wang ◽  
Xiaochen Lyu ◽  
...  
Keyword(s):  
Root System ◽  
Root Nodules ◽  
Culture Conditions ◽  
Sand Culture ◽  
Nodule Formation ◽  
N Fixation ◽  
Fertilizer N ◽  
N Accumulation ◽  
Biological N Fixation ◽  
Nodule Growth

The soybean (Glycine max L. Merr.) is a crop with a high demand for nitrogen (N). The root nodules that form in soybeans can fix atmospheric N effectively, yet the goal of achieving high yields cannot be met by relying solely on nodule-fixed N. Nonetheless, the application of N fertilizer may inhibit nodule formation and biological N fixation (BNF), but the underpinning mechanisms are still unclear. In this study, we grafted the roots of non-nodulated soybeans onto nodulated soybeans to generate plants with dual root system. The experiment included three treatments conducted under sand culture conditions with NO 3 − and NH 4 + as N sources. Treatment I: The non-nodulated roots on one side received 50 mg·L−1 15 NO 3 − or 15NH4+, and the nodulated roots on the other side were not treated. Treatment II: The non-nodulated roots received 50 mg·L−1 15 NO 3 − or 15 NH 4 + , and the nodulated roots received 50 mg·L−1 14 NO 3 − or 14 NH 4 + . Treatment III: Both non-nodulated and nodulated roots received 50 mg·L−1 15 NO 3 − or 15 NH 4 + . The results showed the following: (1) Up to 81.5%–87.1% of the N absorbed by the soybean roots and fixed by the root nodules was allocated to shoot growth, leaving 12.9%–18.5% for root and nodule growth. Soybeans preferentially used fertilizer N in the presence of a NO 3 − or NH 4 + supply. After the absorbed fertilizer N and nodule-fixed N was transported to the shoots, a portion of it was redistributed to the roots and nodules. The N required for root growth was primarily derived from the NO 3 − or NH 4 + assimilated by the roots and the N fixed by the nodules, with a small portion translocated from the shoots. The N required for nodule growth was primarily contributed by nodule-fixed N with a small portion translocated from the shoots, whereas the NO 3 − or NH 4 + that was assimilated by the roots was not directly supplied to the nodules. (2) Based on observations of the shoots and one side of the roots and nodules in the dual root system as an N translocation system, we proposed a method for calculating the N translocation from soybean shoots to roots and nodules during the R1–R5 stages based on the difference in the 15N abundance. Our calculations showed that when adding N at a concentration of 50 mg·L−1, the N translocated from the shoots during the R1–R5 stages accounts for 29.6%–52.3% of the N accumulation in nodulated roots (Rootn) and 9.4%–16.6% of the N accumulation in Nodulen of soybeans. Through the study of this experiment, the absorption, distribution and redistribution characteristics of fertilizer N and root nodule N fixation in soybean can be clarified, providing a theoretical reference for analyzing the mechanisms of the interaction between fertilizer N and nodule-fixed N.

scholarly journals Crop performance, biological N fixation and pre-crop effect of pea ideotypes in an organic farming system

2019 ◽  
Vol 115 (3) ◽  
pp. 391-405 ◽  
Author(s):  
Gabriele Gollner ◽  
Walter Starz ◽  
Jürgen K. Friedel
Keyword(s):  
Grain Yield ◽  
Field Pea ◽  
N Balance ◽  
Grain Legume ◽  
Wheat Crop ◽  
N Fixation ◽  
Site Conditions ◽  
Organic Systems ◽  
Biological N Fixation ◽  
N Concentration

Abstract Pea (Pisum sativum L.) is a valuable grain legume in organic crop rotations. Pea rotations provide nitrogen (N) to the system through N fixation and produce animal feed or human food. Because of the high susceptibility of pea to pests, diseases and weeds and due to low profitability, especially in organic systems, pea cropping intensity decreased in the last 15 years in Austria. Therefore, it is important to find strategies for improving pea cropping systems in organic systems, by increasing yields and providing a positive N balance. The objective of this study was to compare pea genotypes of selected field and fodder pea in pure and mixed pea stands for biomass performance, biological N fixation and pre-crop effect under dry site conditions in a 2-year study in Eastern Austria. Pea N fixation was estimated using the extended N-difference method, with oat as the reference crop. The highest grain yield was found for the leafed field pea, with 2.5 Mg dry mass (DM) ha−1, followed by the semi-leafless field pea with 2.1 Mg DM ha−1 and the pea-mixtures with 2.2 Mg DM ha−1. The field pea cultivars yielded more than the fodder pea cultivars with 1.6 Mg DM ha−1. The average N concentration in pea grains was 3.6 mg g−1. The fodder pea type contained 3.8 mg g−1, significantly more N (p < 0.0001) than the semi-leafless and leafed field pea. Pea N fixation ranged from 53 to 75 kg N ha−1, corresponding to 42–50% of N derived from the atmosphere (% Ndfa). No differences in N fixation were found among cultivars, types and field/fodder pea. The fodder pea exported less N from the field because of their lower grain yield. Therefore, the N balance (N-input − N-output) of fodder pea was positive, with + 3.4 kg N ha−1 compared to the negative N balance of − 0.6 to − 3.6 kg N ha−1 for the leafed field pea types. These differences were not reflected in the following winter wheat crop, where the DM grain yield was 3.6–3.9 Mg ha−1 with no differences between cultivars and ideotypes. The results demonstrate that leafed field pea could have a sufficient grain yield and fodder pea could produce high N concentration in the grains. Because there are no differences regarding the effect of pea types on the yield of the following crop, it can be concluded that all tested pea types are suitable for successful organic pea production under dry site conditions. While there were no negative effects on the subsequent crop, the different ideotypes and mixtures may be selected based on different management goals.

Exotic vascular plant invasiveness and forest invasibility in urban boreal forest types

2006 ◽  
Vol 8 (8) ◽  
pp. 1651-1662 ◽  
Author(s):  
Adele M. Mandryk ◽  
Ross W. Wein
Keyword(s):  
Boreal Forest ◽  
Vascular Plant ◽  
Forest Types ◽  
Plant Invasiveness
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