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    <identifier>10.57760/sciencedb.13779</identifier>
    <datestamp>2023-12-01T15:46:52Z</datestamp>
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<oai_dc:dc xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:date>2023-12-01</dc:date>
  <dc:title>A dataset of the effect of different maize residue on soil organic nitrogen cycling in Li Shu, China</dc:title>
  <dc:identifier>doi:10.57760/sciencedb.13779</dc:identifier>
  <dc:language>en</dc:language>
  <dc:description>Our data contains three parts: nitrogen cycling enzymes, soil organic nitrogen fractions and other soil properties. In the first part, the data of five nitrogen cycling enzymes (protease, N-acetyl-&amp;beta;-D-glucosaminidase (NAG), amidase, urease, and peptidase) were shown with different treatments (RT, NT, TT and PT) and different soil depths (0-10cm, 10-20cm, 20-35cm). Each treatment has four replicates. The methods that obtained these data were as follows: 	Protease activity was&amp;nbsp;measured as described by Ladd and Butler (1972). Field moist soil samples were incubated with 0.05 M Tris buffer (pH 8.10) and 2 % sodium caseinate (w/v) for 2 h at 50 ℃. The tyrosine produced was determined using the colorimetrical method at 700 nm, and the protease activity was expressed as &amp;micro;g tyrosine g&amp;minus;1&amp;nbsp;soil 2 h&amp;minus;1. Amidase activity was assayed using the method described by Frankenberger and Tabatabai (1980). Field moist soil samples were incubated with 0.1 M sodium borate buffer (pH 8.50) and 0.5 M formamide for 2 h at 37 ℃. The ammonium released was determined using the colorimetrical method at 660 nm, and amidase activity was expressed as &amp;micro;g NH4+&amp;nbsp;g&amp;minus;1&amp;nbsp;soil 2 h&amp;minus;1. Soil NAG activity was measured using&amp;nbsp;field moist soil incubated with 0.1 M acetate buffer (pH 5.50) and N-acetyl-&amp;beta;-D-glucosaminide solution at 37 ℃&amp;nbsp;for 1 h. The nitrophenol produced was measured using the colorimetrical method at 405 nm, and the activity of NAG was expressed as mg &amp;rho;-nitrophenol kg&amp;minus;1&amp;nbsp;soil h&amp;minus;1&amp;nbsp;(Parham and Deng, 2000). Soil urease activity was assayed by determining the amount of urea remaining&amp;nbsp;after incubation (Tabatabai, 1994). Field moist&amp;nbsp;soil was incubated with 2 mg mL&amp;minus;1&amp;nbsp;of urea solution at 37 ℃ for 5 h. The residual urea was determined using a colorimetric&amp;nbsp;method at 527 nm. Soil urease activity was expressed as mg urea kg&amp;minus;1soil 5 h&amp;minus;1&amp;nbsp;(Douglas and Bremner, 1970). Soil peptidase activity was measured using a fluorescent substrate&amp;nbsp;(7-amino-4-methylcoumarin). A total of 2.00 g of field-moist soil was weighed and mixed with 200 mL NaN3&amp;nbsp;to produce soil suspension, 50 &amp;mu;L acetate buffer (pH 5.0), 100 &amp;mu;L substrates, and 50 &amp;mu;L soil suspension was then added to a 96-well flat-black-bottomed microplate (NUNC, Denmark) before being incubated for 3 h at 30 ℃.In this study, soil peptidase activity was the sum of the activity of leucine aminopeptidase, glutamate aminopeptidase, and aspartate aminopeptidase. The substrates of these enzymes were L-leucine-AMC, L-glutamic acid-&amp;gamma;-AMC, and aspartic acid-AMC, respectively. The soil peptidase activity was expressed as nmol AMC g&amp;minus;1&amp;nbsp;soil h&amp;minus;1 (Marx et al., 2001; Frossard et al., 2012).In the second part, the data of five organic nitrogen fractions (hydrolyzable NH4+-N, amino acid N, amino sugar N, hydrolyzable unknown&amp;nbsp;N&amp;nbsp;and&amp;nbsp;acid-insoluble N) were shown with different treatments (RT, NT, TT and PT) and different soil depths (0-10cm, 10-20cm, 20-35cm). Each treatment has four replicates. The methods that obtained these data were as follows: 	Organic nitrogen fractions were determined by hydrolyzing the soil sample with 6 M HCl in an autoclave at 121 ℃&amp;nbsp;for 6 h (Stevenson, 1982). Total hydrolyzable N was measured using steam distillation with 10 M NaOH after digestion&amp;nbsp;with sulfuric acid and a K2SO4&amp;nbsp;-catalyst mixture. Amino acid N was determined using steam distillation with a phosphate&amp;ndash;borate buffer after treatment with NaOH at 100 ℃ and ninhydrin powder. Hydrolyzable NH4+-N was measured via steam distillation using MgO.&amp;nbsp;Amino sugar N was calculated as the difference between the amount of N evaporated by steam distillation with phosphate-borate at pH 11.2 and hydrolysable NH4+-N. Hydrolysable unknown-N was calculated as the difference between total hydrolyzable-N and N accounted for as hydrolyzable NH4+&amp;nbsp;+ amino acid + amino sugar) &amp;minus; N. The amount of acid-insoluble N was calculated as the difference between soil TN and total hydrolyzable N. In the third part, the data of other soil properties (MBC, MBN, SOC, SOM, DHA, NH4+, soil pH, Total N of maize straw) were shown with different treatments (RT, NT, TT and PT) and different soil depths (0-10cm, 10-20cm, 20-35cm). Each treatment has four replicates. The methods that obtained these data were as follows: 	Soil microbial biomass carbon&amp;nbsp;(MBC)&amp;nbsp;and microbial biomass nitrogen (MBN)&amp;nbsp;were extracted by 0.5 M K2SO4&amp;nbsp;and were determined using a C and N analyzer (VarioTOC Analyzer, Elementar, Germany)&amp;nbsp;(Mulvaney, 1996).&amp;nbsp;	Soil organic carbon (SOC) was determined by chemical oxidation using K2Cr2O7&amp;nbsp;solution, the SOC oxidized by 0.8 M K2Cr2O7&amp;nbsp;was measured by titrating the remaining K2Cr2O7&amp;nbsp;with 0.2 M FeSO4&amp;nbsp;(Nelson and Sommers, 1982). 	Soil dehydrogenase&amp;nbsp;(DHA)&amp;nbsp;activity was measured using&amp;nbsp;field moist soil incubated with&amp;nbsp;2,3,5-Triphenyltetrazolium chloride solution at 37&amp;nbsp;&amp;deg;C&amp;nbsp;for 24&amp;nbsp;h. The produced 1,3,5-Triphenylformazan was extracted by CH3OH and measured using the colorimetrical method at 485 nm&amp;nbsp;(Tabatabai, 1994).	Soil NH4+-N were extracted by 1 M KCl (Mulvaney, 1996) and were determined using a colorimetric method with an AutoAnalyser III continuous flow analyzer (Bran &amp;amp; Luebbe, Norderstedt, Germany).	Soil pH was determined in a 1:2.5 soil/water suspension by a digital pH meter (pH 700 Bench Meter, Eutech Instruments).	Total N of maize straw was determined using a Vario MACRO cube analyzer (Elementar Analysensysteme Vario MACRO cube, German).ReferenceLadd, J.N., Butler, J.H.A., 1972. Short-term assays of soil proteolytic enzyme activities using proteins and dipeptide derivatives as substrates. Soil Biol. Biochem. 4, 19&amp;ndash;30. Frankenberger, W.T., Tabatabai, M.A., 1980. Amidase activity in soils: I. Method of&amp;nbsp;assay. Soil Sci. Soc. Am. J. 44, 282&amp;ndash;287.Parham, J.A., Deng, S.P., 2000. Detection, quantification and characterization of beta-&amp;nbsp;glucosaminidase activity in soil. Soil Biol. Biochem. 32, 1183&amp;ndash;1190.Tabatabai, M.A., 1994. Soil enzymes. In: Weaver, R.W., Angle, S., Bottomley, P., Bezdicek, D., Smith, S., Tabatabai, A., Wollum, A. (Eds.), Methods of Soil Analysis. Part 2: Microbiological and Biochemical Properties. Soil Science Society of America, Madison, WI, pp. 775&amp;ndash;833.Douglas, L.A., Bremner, J.M., 1970. Extraction and colorimetric determination of urea in&amp;nbsp;soils.&amp;nbsp;Soil Sci. Soc. Am. J. 34, 859&amp;ndash;862.Marx, M.-C., Wood, M., Jarvis, S., 2001. A microplate fluorimetric assay for the study of enzyme diversity in soils. Soil Biol. Biochem. 33, 1633&amp;ndash;1640. Frossard, A., Gerull, L., Mutz, M., Gessner, M.O., 2012. Disconnect of microbial structure and function: enzyme activities and bacterial communities in nascent stream corridors. ISME Journal, 6, 680&amp;ndash;691.Stevenson, F.J., 1982. Organic forms of soil nitrogen. In: Stevenson, F.J. (Ed.), Nitrogen in Agricultural Soils. American Society of Agronomy, Crop Science Society of America, Soil Science Society of America, Madison, pp. 67&amp;ndash;122.Nelson, D.W., Sommers, L.E., 1982. Total carbon, organic carbon, and organic matter. In: Page AL (ed) Methods of soil analysis. Part 2. Chemical and microbiological properties.American Society of Agronomy, Soil Science Society of America, Madison, pp. 539&amp;ndash;579.Mulvaney, R.L., 1996. Nitrogen-inorganic forms, in: Sparks, D.L., Page, A.L., Helmke, P.A., Loeppert, R.H. (Eds.), Methods of soil analysis. Part 3: chemical methods. American Society of Agronomy, Soil Science Society of America, Madison, pp. 1123&amp;ndash;1184.</dc:description>
  <dc:subject>Soil organic nitrogen fractions; Nitrogen cycling enzymes; Organic nitrogen cycling; Crop residue managements; Different soil depths</dc:subject>
  <dc:creator>Su Hongzhi</dc:creator>
  <dc:creator>Zhang Yulan</dc:creator>
  <dc:creator>Wu Guohui</dc:creator>
  <dc:creator>Chen Zhenhua</dc:creator>
  <dc:creator>Jiang Nan</dc:creator>
  <dc:creator>Qiu Weiwen</dc:creator>
  <dc:creator>Chen Lijun</dc:creator>
  <dc:rights>PUBLIC</dc:rights>
  <dc:rights>https://creativecommons.org/publicdomain/zero/1.0/</dc:rights>
  <dc:type>dataset</dc:type>
  <dc:publisher>Science Data Bank</dc:publisher>
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