Water extractable organic carbon and nitrogen and their stable isotopes from long-term experiment in a Japanese rice paddy

• DOI: 10.20527/jwem.v6i2.176
• Publication Date: 2020-07-29T06:52:36Z
• Authors: Toan Nguyen-Sy; Weiguo Cheng; Julien Guigue; Samuel Munyaka Ki...; Wisnu Aji Wibowo; Keitaro Tawaraya; Toru Watanabe; Ji Wu; Xingkai Xu
• Keywords: Isotopes of nitrogen; Carbon fibers; Rice plant; Isotope Analysis; δ15N; Nitrogen Cycle

<span style="color: windowtext; line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt; mso-fareast-font-family: 'ＭＳ 明朝'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;" lang="EN-US">Hot water- and water-extracted organic matter was extracted from soil samples collected after a 31-year long-term experiment which aimed to assess the effect of different fertilization strategies (inorganic fertilizers matters) commonly used for paddy rice cultivation in Yamagata, northeastern Japan. </span><span JA; lang="EN-US">The ratio lang="EN-US">extracted</span><span lang="EN-US"> water 2:3. amounts hot carbon nitrogen (HWEOC HWEN) at 80 <sup>o</sup>C 16 hours, (WEOC WEN) room temperature, their δ<sup>13</sup>C δ<sup>15</sup>N were measured five fertilizer treatment plots as [1) PK, 2) NPK, 3) NPK + 6 Mg ha<sup>-1</sup> straw (RS), 4) 10 compost (CM1), 5) 30 (CM3)], surface (0-15 cm) subsurface (15-25 layers. HWEOC WEOC accounted an average about 1.5</span><span lang="EN-US">1</span><span 0.66% SOC, while HWEN WEN 1.09 0.40% TN, respectively. About 90% N form</span><span among all treatments</span><span lang="EN-US">. The values ranged -28.2 -26.</span><span lang="EN-US">5</span><span lang="EN-US">‰ -28.3 -27.0‰, similar original compost</span><span lang="EN-US">, lower than value -22.5</span><span lang="EN-US">‰. HWEN, bulk 0.</span><span lang="EN-US">8</span><span 3.</span><span lang="EN-US">‰, 1.0</span><span lang="EN-US">to 4.0‰, 2.</span><span It clear that decreased RS but increased CM3 treatments. Our results lang="EN-US">indicated h</span><span lang="EN-US">ot lang="EN-US">were affected by lang="EN-US">application inorganic matter</span><span lang="EN-US">s remarkably. However, lang="EN-US">values HWEOC</span><span lang="EN-US">WEOC</span><span not 5 treatments, lang="EN-US">values</span><span lang="EN-US">δ<sup>15</sup>N lang="EN-US">of lang="EN-US">HWEN lang="EN-US">RS lang="EN-US">and lang="EN-US">CM3 lang="EN-US">applications clearly</span><span lang="EN-US">.</span>