College of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, People's Republic of China.
Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, 210095, People's Republic of China.
Sci Rep. 2021 Jan 14;11(1):1402. doi: 10.1038/s41598-020-80358-2.
The most important measures for salt-affected mudflat soil reclamation are to reduce salinity and to increase soil organic carbon (OC) content and thus soil fertility. Salinity reduction is often accomplished through costly freshwater irrigation by special engineering measures. Whether fertility enhancement only through one-off application of a great amount of OC can improve soil properties and promote plant growth in salt-affected mudflat soil remains unclear. Therefore, the objective of our indoor pot experiment was to study the effects of OC amendment at 0, 0.5%, 1.0%, 1.5%, and 2.5%, calculated from carbon content, by one-off application of sewage sludge on soil properties, rice yield, and root growth in salt-affected mudflat soil under waterlogged conditions. The results showed that the application of sewage sludge promoted soil fertility by reducing soil pH and increasing content of OC, nitrogen and phosphorus in salt-affected mudflat soil, while soil electric conductivity (EC) increased with increasing sewage sludge (SS) application rates under waterlogged conditions. In this study, the rice growth was not inhibited by the highest EC of 4.43 dS m even at high doses of SS application. The SS application increased yield of rice, promoted root growth, enhanced root activity and root flux activity, and increased the soluble sugar and amino acid content in the bleeding sap of rice plants at the tillering, jointing, and maturity stages. In conclusion, fertility enhancement through organic carbon amendment can "offset" the adverse effects of increased salinity and promote plant growth in salt-affected mudflat soil under waterlogged conditions.
受盐影响的滩涂土壤开垦最重要的措施是降低盐分并增加土壤有机碳（OC）含量，从而提高土壤肥力。盐分降低通常通过特殊的工程措施用昂贵的淡水灌溉来实现。通过一次性施加大量 OC 来提高肥力是否仅能改善土壤性质并促进受盐影响的滩涂土壤中的植物生长尚不清楚。因此，我们的室内盆栽实验的目的是研究一次性施加 0、0.5%、1.0%、1.5%和 2.5%（按碳含量计算）的 OC 对受盐影响的滩涂土壤在水涝条件下的土壤性质、水稻产量和根系生长的影响。结果表明，在水涝条件下，施加污泥通过降低土壤 pH 值和增加 OC、氮和磷含量来促进土壤肥力，而土壤电导率（EC）随污泥（SS）施加率的增加而增加。在这项研究中，即使在高剂量 SS 施加的情况下，最高 EC 为 4.43 dS m 也不会抑制水稻生长。SS 的施加增加了水稻的产量，促进了根系生长，增强了根系活力和根液流活力，并增加了分蘗期、拔节期和成熟期水稻植株的伤流液中的可溶性糖和氨基酸含量。总之，通过有机碳施肥来提高肥力可以“抵消”盐分增加的不利影响，并促进水涝条件下受盐影响的滩涂土壤中的植物生长。
