scholarly journals Changes in nitrogen pools in the maize-soil system after urea or straw application to a typical intensive agricultural soil: A 15N tracer study

2020 ◽  
Author(s):  
Jie Zhang ◽  
Ping He ◽  
Dan Wei ◽  
Liang Jin ◽  
Lijuan Zhang ◽  
...  
Keyword(s):  
Rhizosphere Soil ◽  
Bulk Soil ◽  
15N Tracer ◽  
Organic N ◽  
Microbial Biomass N ◽  
Soil System ◽  
Total N ◽  
Available N ◽  
Leaf Stage ◽  
Exogenous Substrate

AbstractA 15N maize pot experiment was conducted to compare the N value of fertilizer alone and fertilizer combined with straw at an equivalent N rate. The four treatments were control (CK), 15N-urea, 15N-urea plus straw, and 15N-straw plus urea. Soil N pools, maize N and their 15N abundance were determined during maize growth. At maturity 26.0% of straw N was assimilated by maize in the urea plus straw treatment. From the eighth leaf stage to maturity, urea plus straw had a significantly (P < 0.05) higher concentration and percentage of exogenous substrate N present as soil total N (TN), particulate organic N (PON), and mineral associated total N (MTN) in bulk and rhizosphere soils than the urea-only treatment. From silking to maturity in the urea plus straw treatment, rhizosphere soil significantly (P < 0.05) increased the percentage of exogenous substrate N present as inorganic N (Inorg-N) and MTN, and significantly (P < 0.05) decreased that present as PON and microbial biomass N (MBN) compared with the bulk soil. From the eighth leaf stage to maturity, rhizosphere soil significantly (P < 0.05) increased the percentage of straw N present as Inorg-N and MTN except for MTN at the silking stage, and significantly decreased (P < 0.05) that present as PON compared with the bulk soil. Overall, straw was an available N source to the crop, and the increase in straw N availability needs to be considered from the interaction of fertilization practices and the crop rhizosphere.

scholarly journals Changes in Nitrogen Pools in the Maize—Soil System after Urea or Straw Application to a Typical Intensive Agricultural Soil: A 15N Tracer Study

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1134
Author(s):  
Jie Zhang ◽  
Ping He ◽  
Dan Wei ◽  
Liang Jin ◽  
Lijuan Zhang ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Chemical Fertilizer ◽  
Bulk Soil ◽  
15N Tracer ◽  
Organic N ◽  
Microbial Biomass N ◽  
Rhizospheric Soil ◽  
Soil System ◽  
Maize Growth ◽  
Biomass N

A maize pot experiment was conducted to compare the difference of N distribution between bulk and rhizospheric soil after chemical fertilizer with or without soil straw amendment at an equivalent N rate using a 15N cross-labeling technique. Soil N pools, maize N and their 15N abundances were determined during maize growth. The urea plus straw treatment significantly (p < 0.05) increased the recovery of urea N in soil and 26.0% of straw N was assimilated by maize. Compared with urea treatment in bulk soil, urea plus straw treatment significantly (p < 0.05) increased the concentration and percentage of applied N as dissolved organic N (DON) and microbial biomass N (MBN) from milk stage to maturity, increased those as particulate organic N (PON) and mineral associated total N (MTN) throughout maize growth and decreased those as inorganic N (Inorg-N) from the eighth leaf to the silking stage. Compared with bulk soil, rhizospheric soil significantly (p < 0.05) decreased the concentration and percentage of applied N as PON and increased those as Inorg-N and MTN in both applied N treatments from the silking stage, and significantly (p < 0.05) decreased the concentration and percentage of applied N as microbial biomass N (MBN) in the urea plus straw treatment. Overall, straw N was an important N source and combined application of chemical fertilizer with straw increased soil fertility, with the rhizosphere regulating the transformation and supply of different N sources in the soil–crop system.

scholarly journals   Distribution of recently fixed photosynthate in a switchgrass plant-soil system

2012 ◽  
Vol 58 (No. 6) ◽  
pp. 249-255 ◽  
Author(s):  
D.R. Chaudhary ◽  
J. Saxena ◽  
N. Lorenz ◽  
R.P. Dick
Keyword(s):  
Panicum Virgatum ◽  
Rhizosphere Soil ◽  
Microbial Biomass Carbon ◽  
Bulk Soil ◽  
Energy Crop ◽  
Marginal Lands ◽  
Soil System ◽  
Plant Soil ◽  
Panicum Virgatum L ◽  
Maintenance Requirements

The use of switchgrass (Panicum virgatum L.) as an energy crop has gained great importance in past two decades due to its high biomass yields on marginal lands with low agricultural inputs and low maintenance requirements. Information on the allocation of photosynthetically fixed C in the switchgrass-soil system is important to understand the C flow and to quantify the sequestration of C in soils. The allocation of <sup>13</sup>C labeled photosynthates in shoot, root, soil, and in microbial biomass carbon (MBC) of rhizosphere and bulk soil of 45 days old, greenhouse grown-switchgrass was examined during 20 days <sup>13</sup>C-CO<sub>2</sub> pulse labeling period. The total <sup>13</sup>C recovered in the plant-soil system varied from 79% after 1 day to 42% after 20 days of labeling. After labeling, 54%, 40%, and 6% excess <sup>13</sup>C resided in shoot, root and soil, respectively on day 1; 27%, 61% and 11%, respectively on day 5 and 20%, 63% and 17%, respectively day 20 after labeling. The maximum incorporation of <sup>13</sup>C from roots into the MB of rhizosphere soil occurred within the first 24 h of labeling. The excess <sup>13</sup>C values of rhizosphere soil and rhizosphere MBC were significantly higher than excess <sup>13</sup>C values of bulk soil and the bulk soil MBC, respectively. The proportion of excess <sup>13</sup>C in soil as MBC declined from 92 to 15% in rhizosphere soil and from 79 to 18% in bulk soil, for 1 day and 20 days after labeling, respectively. The present study showed the effectiveness of <sup>13</sup>C labeling to examine the fate of recently photosynthesized C in soil-plant (switchgrass) system and dynamics of MBC. &nbsp;

scholarly journals The Transformation Dynamics and Homogeneity of Different N Fractions in Compost Following Glucose Addition

Agriculture ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 971
Author(s):  
Caibin Li ◽  
Shuai Ding ◽  
Chenghang Du ◽  
Yi He ◽  
Zemeng Ma ◽  
...  
Keyword(s):  
Isotopic Labeling ◽  
Scientific Basis ◽  
Hot Water ◽  
Organic N ◽  
Microbial Biomass N ◽  
Mineral N ◽  
Available N ◽  
Microbial Responses ◽  
N Fractions ◽  
Time Point

The application of compost to soil is a common fertilization practice for improving soil quality and crop growth. The isotopic labeling technique is mostly used to investigate the contribution of compost N to crop uptake. However, compost N includes various N fractions and labeling dissimilarity, which may cause bias when calculating the compost N contribution to plants. Therefore, the labeling dynamics of different N fractions in compost and the homogenous labeling time point should be clarified. Given the 15N-labeling in chemical fertilizer and the carbon source, i.e., glucose, the compost N pools were divided into active N (mineral N, soluble organic N [SON], microbial biomass N [MBN]), stable N (hot-water extractable organic N [HWDON]), and recalcitrant N. The atom percentage excess (APE) of different N in compost notably varied at the beginning of incubation, ranging from 0–3.7%. After the addition of glucose, biological N immobilization was promoted (13.7% and 28.8% for MBN and HWDON, respectively) and promoted the transformation among available N pools. Adding distinct doses of glucose at three stages to 15N-labeled compost resulted in diverse microbial responses, thereby redistributing exogenous N in each fraction (15NH4+-N went into SO15N from day 15 to day 30 and increased by 5.1%; SO15N entered MB15N and HWDO15N during day 30 to day 45 and increased by 5.7% and 5.2%, respectively). On day 45, homogeneous 15N-labeled compost was achieved, which was 2.4% for 15N APE for all N fractions. Overall, the quantitative data for the transformation of N fractions in compost at distinct stages provides a scientific basis for compost labeling trials, in order to identify the time point at which compost N-labeling is homogeneous, which is necessary and meaningful to reduce the bias of the contribution rate of compost-N to plants.

scholarly journals Protist diversity and community complexity in the rhizosphere of switchgrass are dynamic as plants develop

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Javier A. Ceja-Navarro ◽  
Yuan Wang ◽  
Daliang Ning ◽  
Abelardo Arellano ◽  
Leila Ramanculova ◽  
...  
Keyword(s):  
Community Composition ◽  
Community Assembly ◽  
Panicum Virgatum ◽  
Large Scale ◽  
Rhizosphere Soil ◽  
Bacterial Community Composition ◽  
Temporal Variations ◽  
Bulk Soil ◽  
Growth Stages ◽  
Soil System

Abstract Background Despite their widespread distribution and ecological importance, protists remain one of the least understood components of the soil and rhizosphere microbiome. Knowledge of the roles that protists play in stimulating organic matter decomposition and shaping microbiome dynamics continues to grow, but there remains a need to understand the extent to which biological and environmental factors mediate protist community assembly and dynamics. We hypothesize that protists communities are filtered by the influence of plants on their rhizosphere biological and physicochemical environment, resulting in patterns of protist diversity and composition that mirror previously observed diversity and successional dynamics in rhizosphere bacterial communities. Results We analyzed protist communities associated with the rhizosphere and bulk soil of switchgrass (SG) plants (Panicum virgatum) at different phenological stages, grown in two marginal soils as part of a large-scale field experiment. Our results reveal that the diversity of protists is lower in rhizosphere than bulk soils, and that temporal variations depend on soil properties but are less pronounced in rhizosphere soil. Patterns of significantly prevalent protists groups in the rhizosphere suggest that most protists play varied ecological roles across plant growth stages and that some plant pathogenic protists and protists with omnivorous diets reoccur over time in the rhizosphere. We found that protist co-occurrence network dynamics are more complex in the rhizosphere compared to bulk soil. A phylogenetic bin-based null model analysis showed that protists’ community assembly in our study sites is mainly controlled by homogenous selection and dispersal limitation, with stronger selection in rhizosphere than bulk soil as SG grew and senesced. Conclusions We demonstrate that environmental filtering is a dominant determinant of overall protist community properties and that at the rhizosphere level, plant control on the physical and biological environment is a critical driver of protist community composition and dynamics. Since protists are key contributors to plant nutrient availability and bacterial community composition and abundance, mapping and understanding their patterns in rhizosphere soil is foundational to understanding the ecology of the root-microbe-soil system.

Loss of nitrogen and carbon during storage of the fibrous fraction of separated pig slurry and influence on nitrogen availability

2008 ◽  
Vol 146 (4) ◽  
pp. 403-413 ◽  
Author(s):  
J. PETERSEN ◽  
P. SØRENSEN
Keyword(s):  
Nitrogen Availability ◽  
Application Rate ◽  
Organic N ◽  
Pig Slurry ◽  
Volatile Elements ◽  
Total N ◽  
Available N ◽  
Ammonium N ◽  
On Farm

SUMMARYManure production in the most livestock-intensive areas exceeds the crop demand for nutrients and legislative restrictions on application rate cause a shortage of land for manure application. Export of nutrients in the fibrous fraction of separated animal slurry has become an option for sustaining or increasing livestock production in livestock-intensive areas. The nitrogen (N) and carbon (C) losses during on-farm storage of the fibrous fraction, originating from separation of anaerobically digested pig slurry using the non-volatile elements phosphorus (P), copper (Cu) and zinc (Zn) as internal references, were calculated. In addition, the plant availability of N in fresh and stored fibrous fractions was evaluated in an incubation experiment. The losses of N and C were greater from the heap surface than from the centre, and turning the heap by reloading for transport increased the losses. The proportion of ammonium N, total N and C lost during storage of the fibrous fraction was 0·30–0·90, 0·10–0·55 and 0·35–0·70 of the initial amount, respectively. Storage reduced the plant-available N and the amount of residual organic N, thereby having long-term influence on soil fertility. The plant-available N in fresh fibrous fractions was 0·22–0·52 of total N, but decreased to 0·15–0·38 after storage due to a decrease of the Nammonium:Ntotal ratio during storage. The net mineralization of manure N was negatively related to the Ctotal:Norganic ratio. The fibrous fraction of separated pig slurry may be characterized as a manure with a high potential for loss and a variable value as fertilizer.

A new approach to quantifying the N benefit from pasture legumes to succeeding wheat

1998 ◽  
Vol 49 (3) ◽  
pp. 427 ◽  
Author(s):  
Ann M. McNeill ◽  
Chunya Zhu ◽  
Ian R. P. Fillery
Keyword(s):  
Subterranean Clover ◽  
Bulk Soil ◽  
Residual Fraction ◽  
15N Tracer ◽  
Soil Columns ◽  
Total N ◽  
Plant Soil ◽  
Soil Systems ◽  
Peak Biomass ◽  
Below Ground

Vegetative subterranean clover (Trifolium subterraneum L.) and serradella (Ornithopus compressus L.), growing in 1-m soil columns under glasshouse conditions during 1994, were fed 15N tracer by immersion of individual leaves (5 per plant) in a 0·4% (w/w) solution of labelled urea (99·6 atom% 15N). Four replicate soil-plant systems were harvested in late October 1994 at legume peak biomass (41 days after labelling) and in early December 1994 at maturity (90 days after labelling). The shoots were removed and the soil columns fractionated into clean macro-root, residual (root/soil) fraction, and bulk soil; the shoots from the remaining replicates were also harvested at maturity leaving the labelled soil columns intact. These intact columns were kept dry for 5 months during the summer then rewetted and planted with wheat in June 1995. Four replicate soil-plant systems were harvested at planting, tillering, anthesis, and maturity of the wheat and fractionated as before. Mean recovery of fed 15N by the plant{soil systems was 42% for subterranean clover and 64% for serradella. Proportional distribution of the recovered 15N was similar for both plant-soil systems: 67-69% recovered above-ground and 31-33% recovered below-ground for subterranean clover compared with 71-75% above-ground and 25-29% below-ground for serradella. Uniform labelling of below-ground nitrogen (BG N) enabled estimation of total BG N accumulation, under undisturbed conditions, for the two pasture species. Less than 60% of the total legume BG N for both species was recovered as macro-root, with up to 17% recovered in the residual fraction and 33-51% in the bulk soil. Subterranean clover increased its total amount of BG N from 174 to 218 mg/plant between peak biomass and maturity with >65% of this located in the top 10 cm of the soil. Total BG N for serradella was similar at peak biomass (172 mg/plant) and not only decreased slightly by maturity (160 mg/plant) but was also redistributed to depth between the 2 sampling times. The ratio of shoot N to total BG N at peak biomass was 1 : 0·68 for subterranean clover and 1 : 0·60 for serradella. Recovery of labelled legume BG N at harvest by wheat following subterranean clover was 25% and after serradella was 18%. Root residues from subterranean clover appeared to decompose more rapidly than those from serradella, manifest by rapid uptake by the succeeding wheat so that 66% of the total N benefit had accrued by tillering, whereas only 44% of the N benefit from serradella roots had accrued by tillering and 72% by anthesis.

Nitrogen dynamics in soil amended with composted cattle manure

2007 ◽  
Vol 87 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Bobbi L Helgason ◽  
Francis J Larney ◽  
H. Henry Janzen ◽  
Barry M Olson
Keyword(s):  
N Uptake ◽  
Wood Chip ◽  
N Fertilizer ◽  
Organic N ◽  
Inorganic N ◽  
Available Nitrogen ◽  
N Content ◽  
Total N ◽  
Available N ◽  
Plant Available Nitrogen

The amount and pattern of plant-available nitrogen (N) release from composts are variable and not well-defined. We used a 425-d canola (Brassica napus L.) bioassay to follow the release of N from eight composted cattle manures applied to soil at 20 g kg-1. Two stockpiled manures, one inorganic fertilizer and an unamended control were also included for comparison. Eight consecutive 30-d growth cycles were conducted in a controlled environment chamber (20°C) and plant N uptake was measured. Total N uptake was greatest from the N fertilizer and least from the wood-chip bedded manure. Addition of compost increased N uptake by 27–99% compared with that in the control. Nitrogen uptake from compost was directly proportional to its inorganic N content (r2 = 0.98; P < 0.0001) showing that the initial inorganic N content of compost, analyzed prior to its application can be used to predict plant available N. In seven of the eight composts studied, less than 5% of organic N was mineralized over 425 d, suggesting that little of the organic N in compost becomes available in the year of application. Compost is a valuable organic amendment, but co-application of N fertilizer is recommended to supply adequate N and optimize the benefits of compost for crop growth. Key words: Plant-available nitrogen, compost, nitrogen mineralization, beef manure

scholarly journals Growing Legumes in Orchard Alleys as an Internal Nitrogen Source

HortScience ◽  
2017 ◽  
Vol 52 (9) ◽  
pp. 1283-1287 ◽  
Author(s):  
David Granatstein ◽  
Joan R. Davenport ◽  
Elizabeth Kirby
Keyword(s):  
Plant Root ◽  
Perennial Grass ◽  
Soil Disturbance ◽  
Apple Orchard ◽  
Organic N ◽  
Grass Cover ◽  
Tree Roots ◽  
Total N ◽  
Available N ◽  
Exchange Resins

The drive alley in modern apple (Malus ×domestica Bork.) orchards often receives enough light to grow plants other than the typical perennial grass cover. By planting leguminous species in this area, it is possible to produce a portion of the nitrogen needs of the orchard by mowing the vegetation and blowing it onto the tree row where it mineralizes and releases available N over the tree roots. Four perennial legume species [alfalfa (Medicago sativa L.), ladino white clover (Trifolium repens L.), birdsfoot trefoil (Lotus corniculatus L.), kura clover (Trifolium ambiguum L.)] were compared with the resident grass cover crop in a mature apple orchard. All legumes were direct-seeded into the alley to avoid any soil disturbance and were successfully established. Legume biomass and tissue N were monitored, along with biweekly monitoring of tree row soil nitrogen with both soil sampling and ion exchange resins using Plant Root Simulator® probes. Four mowings of alfalfa contained ≈43 kg total N/ha that was added to the tree row during the second season (2009), with a dry matter C:N of 10.8. Economically, legume nitrogen appears to be less expensive than other sources of organic N and may be cost competitive with synthetic fertilizer N when prices are high.

scholarly journals Bacillus subtilis HG-15, a Halotolerant Rhizoplane Bacterium, Promotes Growth and Salinity Tolerance in Wheat (Triticum aestivum)

2020 ◽  
Author(s):  
Chao Ji ◽  
Huimei Tian ◽  
Xiaohui Wang ◽  
Liping Hao ◽  
Changdong Wang ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Salt Stress ◽  
Plant Growth ◽  
Rhizosphere Soil ◽  
Yellow River ◽  
Plant Growth Promoting Bacteria ◽  
Total N ◽  
Available N ◽  
Plant Growth Promoting ◽  
Growth Promoting

Abstract Background : Certain plant growth-promoting bacteria (PGPB) reduce salt stress damage in plants. Bacillus subtilis HG-15 is a halotolerant bacterium (able to withstand NaCl concentrations as high as 30%) isolated from the wheat rhizoplane in the Yellow River delta. A qualitative and quantitative investigation of the plant growth-promoting characteristics of this strain confirmed nitrogen fixation, potassium dissolution, and ammonia, plant hormone, 1-aminocyclopropane-1-carboxylic acid deaminase, and proline production abilities. B. subtilis HG-15 colonization of wheat roots, stems, and leaves was examined via scanning electron microscopy , rep-PCR, and double antibiotic screening.Results : Compared with a no B. subtilis HG-15 treatment control, in rhizosphere soil inoculated with the HG-15 strain, the pH (1.08–2.69%), electrical conductivity (3.17–11.48%), and Na + (12.98–15.55%) concentrations significantly decreased ( p < 0.05). Inoculation with the HG-15 strain increased the total N, available N, organic matter, K + , Ca 2+ , and Mg 2+ concentrations in the rhizosphere soil of wheat. Under non-salt stress (0.15% NaCl), low-salt stress (0.25% NaCl), and high-salt stress (0.35% NaCl) conditions, respectively, this strain also significantly increased ( p < 0.05) the dry weight (17.76%, 24.46%, 9.31%), fresh weight (12.80%, 20.48%, 7.43%), plant height (7.79%, 5.86%, 13.13%), root length (10.28%, 17.87%, 48.95%), and other wheat parameters. Through redundancy analysis and Pearson correlation analyses, photosynthesis, biomass accumulation, and osmotic regulation by the wheat plants showed a significant negative correlation with pH, EC, and Na + concentrations in rhizosphere soil.Conclusions : Our results indicated that B . subtilis HG-15 can effectively improve the growth of wheat and elicit induced systemic tolerance in these plant, thus, showing its potential as a microbial inoculant that can protect wheat in salt stress conditions. Furthermore, we determined that the rhizoplane of saline-alkali land plants is an important reservoir for salt-tolerant PGPB.

scholarly journals Nitrogen uptake strategies of mature conifers in Northeastern China, illustrated by the 15N natural abundance method

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Xulun Zhou ◽  
Ang Wang ◽  
Erik A. Hobbie ◽  
Feifei Zhu ◽  
Xueyan Wang ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
N Uptake ◽  
Natural Abundance ◽  
Pinus Koraiensis ◽  
Organic N ◽  
Larix Olgensis ◽  
Total N ◽  
Available N ◽  
N Sources ◽  
Picea Koraiensis

Abstract Background Conifers partition different N forms from soil, including ammonium, nitrate, and dissolved organic N (DON), to sustain plant growth. Previous studies focused on inorganic N sources and specific amino acid forms using 15N labelling, but knowledge of the contribution of DON to mature conifers’ N uptake is still scarce. Here, we quantified the contribution of different N forms (DON vs. NH4+ vs. NO3−) to total N uptake, based on 15N natural abundance of plant and soil available N, in four mature conifers (Pinus koraiensis, Pinus sylvestris, Picea koraiensis, and Larix olgensis). Results DON contributed 31%, 29%, 28%, and 24% to total N uptake by Larix olgensis, Picea koraiensis, Pinus koraiensis, and Pinus sylvestris, respectively, whereas nitrate contributed 42 to 52% and ammonium contributed 19 to 29% of total N uptake for these four coniferous species. Conclusions Our results suggested that all four conifers could take up a relatively large proportion of nitrate, while DON was also an important N source for the four conifers. Given that DON was the dominant N form in study soil, such uptake pattern of conifers could be an adaptive strategy for plants to compete for the limited available N sources from soil so as to promote conifer growth and maintain species coexistence.

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