Xu Bo, Li Hongyu, Wang Qiuju, Li Quanfeng, Sha Yan, Ma Chen, Yang Aizheng, Li Mo
Key Laboratory of Efficient Use of Agricultural Water Resources of Ministry of Agriculture and Rural Affairs of the People's Republic of China, Northeast Agricultural University, Harbin, China.
School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, China.
Front Plant Sci. 2024 Sep 20;15:1441649. doi: 10.3389/fpls.2024.1441649. eCollection 2024.
The combination of biochar and nitrogen (N) fertilization in agricultural salt-affected soils is an effective strategy for amending the soil and promoting production. To investigate the effect of nitrogen reduction combined with biochar application on a soda saline soil and soybean growth in black soil areas, a pot experiment was set up with two biochar application levels, 0 (B0) and 4.5 t/hm2 (B1); two biochar application depths, 0-20 cm (H1) and 0-40 cm (H2); and two nitrogen application levels, conventional nitrogen application (N0) and nitrogen reduction of 15% (N1). The results showed that the application of biochar improved the saline soil status and significantly increased soybean yield under lower nitrogen application. Moreover, increasing the depth of biochar application enhanced the effectiveness of biochar in reducing saline soil barriers to crop growth, which promoted soybean growth. Increasing the depth of biochar application increased the K+ and Ca2+ contents, soil nitrogen content, N fertilizer agronomic efficiency, leaf total nitrogen, N use efficiency, AN, Tr, gs, SPAD, leaf water potential, water content and soybean yield and its components. However, the Na+ content, SAR, ESP, Na+/K+, Ci and water use efficiency decreased with increasing biochar depth. Among the treatments with low nitrogen input and biochar, B1H1N1 resulted in the greatest soil improvement in the 0-20 cm soil layer compared with B0N0; for example, K+ content increased by 61.87%, Na+ content decreased by 44.80%, SAR decreased by 46.68%, and nitrate nitrogen increased by 26.61%. However, in the 20-40 cm soil layer, B1H2N1 had the greatest effect on improving the soil physicochemical properties, K+ content increased by 62.54%, Na+ content decreased by 29.76%, SAR decreased by 32.85%, and nitrate nitrogen content increased by 30.77%. In addition, compared with B0N0, total leaf nitrogen increased in B1H2N1 by 25.07%, N use efficiency increased by 6.7%, N fertilizer agronomic efficiency increased by 32.79%, partial factor productivity of nitrogen increased by 28.37%, gs increased by 22.10%, leaf water potential increased by 27.33% and water content increased by 6.44%. In conclusion, B1H2N1 had the greatest effect on improving the condition of saline soil; it not only effectively regulated the distribution of salt in soda saline soil and provided a low-salt environment for crop growth but also activated deep soil resources. Therefore, among all treatments investigated in this study, B1H2N1 was considered most suitable for improving the condition of soda saline soil in black soil areas and enhancing the growth of soybean plants.
在农业盐碱化土壤中，生物炭与氮肥结合是改良土壤和促进生产的有效策略。为了研究减氮结合施用生物炭对苏打盐碱土及黑土区大豆生长的影响，设置了盆栽试验，包括两个生物炭施用量水平，0（B0）和4.5吨/公顷（B1）；两个生物炭施用深度，0 - 20厘米（H1）和0 - 40厘米（H2）；以及两个氮肥施用量水平，常规施氮（N0）和减氮15%（N1）。结果表明，施用生物炭改善了盐碱土状况，并在较低施氮量下显著提高了大豆产量。此外，增加生物炭施用深度增强了生物炭减少盐碱土对作物生长障碍的有效性，促进了大豆生长。增加生物炭施用深度提高了K⁺和Ca²⁺含量、土壤氮含量、氮肥农学效率、叶片全氮、氮素利用效率、净光合速率（AN）、蒸腾速率（Tr）、气孔导度（gs）、叶绿素含量（SPAD）、叶片水势、含水量以及大豆产量及其构成因素。然而，随着生物炭深度增加，Na⁺含量、钠吸附比（SAR）、交换性钠百分比（ESP）、Na⁺/K⁺、胞间二氧化碳浓度（Ci）和水分利用效率降低。在低氮投入和生物炭处理中，与B0N0相比，B1H1N1在0 - 20厘米土层对土壤改良效果最佳；例如，K⁺含量增加了61.87%，Na⁺含量降低了44.80%，SAR降低了46.68%，硝态氮增加了26.61%。然而，在20 - 40厘米土层，B1H2N1对改善土壤理化性质效果最佳，K⁺含量增加了62.54%，Na⁺含量降低了29.76%，SAR降低了32.85%，硝态氮含量增加了30.77%。此外，与B0N0相比，B1H2N1的叶片全氮增加了(25.07%)，氮素利用效率提高了(6.7%)，氮肥农学效率提高了(32.79%)，氮肥偏生产力提高了(28.37%)，gs增加了(22.10%)，叶片水势增加了(27.33%)，含水量增加了(6.44%)。总之，B1H2N1对改善盐碱土状况效果最佳；它不仅有效调节了苏打盐碱土中盐分的分布，为作物生长提供了低盐环境，还激活了深层土壤资源。因此，在本研究调查的所有处理中，B1H2N1被认为最适合改善黑土区苏打盐碱土状况并促进大豆植株生长。
