Zhang Jiuming, Li Yan, Yuan Jiahui, Chi Fengqin, Kuang Enjun, Zhu Yingxue, Sun Lei, Wei Dan, Liu Jie
Key Laboratory of Black Soil Protection and Utilization, Ministry of Agriculture and Rural Affairs, Heilongjiang Academy of Black Soil Conservation and Utilization, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China.
Institute of Plant Nutrition, Resources and Environment, Beijing Academy of Agricultural and Forestry Sciences, Beijing, 100097, China.
Sci Rep. 2024 Dec 2;14(1):29948. doi: 10.1038/s41598-024-72050-6.
Straw return improves soil carbon pool and dissolved organic matter (DOM) characteristics in black soil. Optimal straw return rate is the key to promoting straw return practices in farmland in Northeast China. The experiment was conducted at the Science and Technology Park of China Grain Storage and Northern Corporation in NenJiang, Heilongjiang Province, straw return at 0 kg hm, 3000 kg hm, 4500 kg hm, and 9000 kg hm. In the seventh year of the experiment, we used three-dimensional excitation-emission matrices combined with Parallel Factor analysis to characterize the fluorescence characteristics of DOM of black soils. The results showed substantial improvement in soil physical characteristics and soil organic matter (SOM) following straw return, SOM content rises in proportion to the amount of straw returned, and a significant positive correlation coefficient between water-holding capacity (WHC) (p < 0.001, r = 0.82) and dissolved organic matter (DOC) (p < 0.01, r = 0.77). Moreover, straw return significantly increased the richness of three fluorescent components, namely fulvic acid (UV and visible fulvic acids), humic-like acid, and protein-like (short and long-wavelength tryptophan). The fluorescence intensities of these components were lower in straw treatments than in no straw return. The fluorescence intensities of fulvic and humic acids showed decreasing and increasing trends, respectively, with increasing straw return amount. The fluorescence spectroscopy data of DOC demonstrated the key role of high straw return amounts in enhancing substantially the metabolic activity of soil microorganisms. Overall, straw-returning practices improve soil fertility and can be beneficial for black soil farmlands, with the optimal return rate observed at 4500 kg hm.
秸秆还田改善了黑土的土壤碳库和溶解有机物（DOM）特征。最佳秸秆还田率是促进中国东北农田秸秆还田实践的关键。试验在黑龙江省嫩江市中国储备粮北方公司科技园进行，秸秆还田量分别为0 kg·hm、3000 kg·hm、4500 kg·hm和9000 kg·hm。在试验的第七年，我们使用三维激发-发射矩阵结合平行因子分析来表征黑土DOM的荧光特征。结果表明，秸秆还田后土壤物理特性和土壤有机质（SOM）有显著改善，SOM含量与秸秆还田量成正比，持水量（WHC）（p＜0.001，r = 0.82）与溶解有机物（DOC）（p＜0.01，r = 0.77）之间存在显著正相关系数。此外，秸秆还田显著增加了三种荧光组分的丰富度，即富里酸（紫外和可见富里酸）、类胡敏酸和类蛋白（短波长和长波长色氨酸）。这些组分在秸秆处理中的荧光强度低于不进行秸秆还田的处理。随着秸秆还田量增加，富里酸和胡敏酸的荧光强度分别呈下降和上升趋势。DOC的荧光光谱数据表明，高秸秆还田量在显著增强土壤微生物代谢活性方面起着关键作用。总体而言，秸秆还田实践改善了土壤肥力，对黑土农田有益，最佳还田率为4500 kg·hm。
