Effects of long-term straw incorporation on lignin accumulation and its association with bacterial laccase-like genes in arable soils

2019 ◽  
Vol 103 (4) ◽  
pp. 1961-1972 ◽  
Author(s):  
Shuzhen Feng ◽  
Yirong Su ◽  
Xunyang He ◽  
Yajun Hu ◽  
Zhenhua Zhang ◽  
...  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ian M. Clark ◽  
Qingling Fu ◽  
Maïder Abadie ◽  
Elizabeth R. Dixon ◽  
Aimeric Blaud ◽  
...  

Abstract Factors influencing production of greenhouse gases nitrous oxide (N2O) and nitrogen (N2) in arable soils include high nitrate, moisture and plants; we investigate how differences in the soil microbiome due to antecedent soil treatment additionally influence denitrification. Microbial communities, denitrification gene abundance and gas production in soils from tilled arable plots with contrasting fertilizer inputs (no N, mineral N, FYM) and regenerated woodland in the long-term Broadbalk field experiment were investigated. Soil was transferred to pots, kept bare or planted with wheat and after 6 weeks, transferred to sealed chambers with or without K15NO3 fertilizer for 4 days; N2O and N2 were measured daily. Concentrations of N2O were higher when fertilizer was added, lower in the presence of plants, whilst N2 increased over time and with plants. Prior soil treatment but not exposure to N-fertiliser or plants during the experiment influenced denitrification gene (nirK, nirS, nosZI, nosZII) relative abundance. Under our experimental conditions, denitrification generated mostly N2; N2O was around 2% of total gaseous N2 + N2O. Prior long-term soil management influenced the soil microbiome and abundance of denitrification genes. The production of N2O was driven by nitrate availability and N2 generation increased in the presence of plants.


2018 ◽  
Vol 13 (No. 3) ◽  
pp. 140-149 ◽  
Author(s):  
Šimanský Vladimír ◽  
Lukáč Martin

Soil structure is a key determinant of many soil environmental processes and is essential for supporting terrestrial ecosystem productivity. Management of arable soils plays a significant role in forming and maintaining their structure. Between 1994 and 2011, we studied the influence of soil tillage and fertilisation regimes on the stability of soil structure of loamy Haplic Luvisol in a replicated long-term field experiment in the Dolná Malanta locality (Slovakia). Soil samples were repeatedly collected from plots exposed to the following treatments: conventional tillage (CT) and minimum tillage (MT) combined with conventional (NPK) and crop residue-enhanced fertilisation (CR+NPK). MT resulted in an increase of critical soil organic matter content (St) by 7% in comparison with CT. Addition of crop residues and NPK fertilisers significantly increased St values (by 7%) in comparison with NPK-only treatments. Soil tillage and fertilisation did not have any significant impact on other parameters of soil structure such as dry sieving mean weight diameters (MWD), mean weight diameter of water-stable aggregates (MWD<sub>WSA</sub>), vulnerability coefficient (Kv), stability index of water-stable aggregates (Sw), index of crusting (Ic), contents of water-stable macro- (WSA<sub>ma</sub>) and micro-aggregates (WSA<sub>mi</sub>). Ic was correlated with organic matter content in all combinations of treatments. Surprisingly, humus quality did not interact with soil management practices to affect soil structure parameters. Higher sums of base cations, CEC and base saturation (Bs) were linked to higher Sw values, however higher values of hydrolytic acidity (Ha) resulted in lower aggregate stability in CT treatments. Higher content of K<sup>+</sup> was responsible for higher values of MWD<sub>WSA </sub>and MWD in CT. In MT, contents of Ca<sup>2+</sup>, Mg<sup>2+ </sup>and Na<sup>+</sup> were significantly correlated with contents of WSA<sub>mi </sub>and WSA<sub>ma</sub>. Higher contents of Na<sup>+</sup> negatively affected St values and positive correlations were detected between Ca<sup>2+</sup>, Mg<sup>2+ </sup>and Na<sup>+</sup> and Ic in NPK treatments.


Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 456 ◽  
Author(s):  
Massimiliano Cardinale ◽  
Stefan Ratering ◽  
Aitak Sadeghi ◽  
Sushil Pokhrel ◽  
Bernd Honermeier ◽  
...  

The effects of different agronomic practices, such as fertilization regimes, can be experimentally tested in long-term experiments (LTE). Here, we aimed to evaluate the effect of different nitrogen fertilizations on the bacterial microbiota in both rhizosphere and bulk soil of sugar beet, in the Giessen-LTE (Germany). Fertilization treatments included mineral-N, manure, mineral-N + manure and no N-amendment. Metabarcoding and co-occurrence analysis of 16S rRNA genes, qPCR of amoA, nirK, nirS, nosZ-I and nosZ-II genes and soil physico-chemical analyses were performed. The effect of the fertilization treatments was more evident in the bulk soil, involving 33.1% of the microbiota. Co-occurrence analysis showed a rhizosphere cluster, dominated by Proteobacteria, Actinobacteria and Verrucomicrobia (hub taxa: Betaproteobacteriales), and a bulk soil cluster, dominated by Acidobacteria, Gemmatominadetes and “Latescibacteria” (hub taxa: Acidobacteria). In the bulk soil, mineral N-fertilization reduced nirK, amoA, nosZ-I and nosZ-II genes. Thirteen Operational taxonomic units (OTUs) showed 23 negative correlations with gene relative abundances. These OTUs likely represent opportunistic species that profited from the amended mineral-N and outgrew the species carrying N-cycle genes. Our results indicate trajectories for future research on soil microbiome in LTE and add new experimental evidence that will be helpful for sustainable management of nitrogen fertilizations on arable soils.


1998 ◽  
Vol 131 (3) ◽  
pp. 309-320 ◽  
Author(s):  
J. A. CATT ◽  
K. R. HOWSE ◽  
D. G. CHRISTIAN ◽  
P. W. LANE ◽  
G. L. HARRIS ◽  
...  

Nitrate loss in drainwater and cultivated layer flow was measured over 5 years on two pairs of hydrologically isolated plots, one pair with cereal straw incorporated for 4 years and burnt in the fifth, and the other with straw burnt in all 5 years. Although straw incorporation decreased nitrate leaching and probably decreased net mineralization of soil organic matter in the first winter, these effects were apparently diminished or even reversed in later winters, and the straw had no benefit on cereal yields or N-uptakes. The results suggest that the present practice on UK farms of regularly incorporating cereal straw is unlikely to decrease nitrate losses and in the long term may increase them, especially on clay soils and in wet winters after long dry periods. On clay soils it is also unlikely to increase crop yields in the short or medium term.


Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 737 ◽  
Author(s):  
D. Curtin ◽  
F. M. McCallum

Nitrogen (N) mineralised from soil organic matter can be an important source of N for crop uptake, particularly following cultivation of pastures. Difficulty in predicting the contribution of mineralisation continues to be a serious obstacle to implementating best management practices for fertiliser N. We evaluated biological tests (i.e. net N mineralised in a 28-day aerobic incubation and anaerobically mineralisable N, AMN) and chemical tests (ammonium-N hydrolysis in hot 2 m KCl) as predictors of N supply to a glasshouse-grown oat (Avena sativa L.) crop. The oat plants were grown to maturity without added N on 30 soils representing a range of management histories, including soils collected from long-term pastures and intensive arable cropping sites. The majority (average 83%) of the N accumulated in grain and straw was mineralised N. Plant N derived from mineralisation (PNDM), estimated by subtracting soil mineral N at sowing from N uptake, was generally higher for long-term pasture soils (mean 82 mg/kg, n = 9) than for long-term arable soils (mean 48 mg/kg, n = 9). The 2 measures of N mineralisation were not closely related [R2 = 0.11 (0.37*** when one outlying observation was omitted)], indicating that aerobic and anaerobic assays can give quite different N fertility rankings. Aerobically mineralisable N was the best predictor of PNDM (R2 = 0.79***). The ratio of CO2-C evolved to net N mineralised in the aerobic incubation was highly variable (e.g. mean of 13.6 for pasture soils v. 7.5 for long-term arable soils), likely due to differences in N immobilisation. The correlations of AMN (R2 = 0.32**) and hot KCl N (R2 = 0.24**) with PNDM were not much better than that between total soil N and PNDM (R2 = 0.16*), suggesting that these tests would not provide reliable estimates of N mineralisation potential in soils with diverse management histories.


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