减氮配施生物炭对苏打盐碱土壤环境与大豆生长特性的影响

Effect of Nitrogen Reduction with Biochar Application on Soda Saline Soil Environment and Growth Characteristics of Soybean

摘要:

土壤盐碱化是制约黑土区苏打盐碱地农业可持续发展的重要因素。本研究通过盆栽试验探究减氮配施生物炭及其施加深度对苏打盐碱土壤环境以及大豆生长特性的影响，共设置2个生物炭施加水平：0t/hm2(B0)、4.5t/hm2 (B1)，2个生物炭施用深度：0~20cm (H1)、0~40cm (H2)，3个施氮水平：常规施氮 (N0)、减氮15% (N1)、减氮30% (N2)。试验结果表明：在减氮条件下，施加生物炭可以改善盐碱土壤环境并显著提升大豆产量。同时，随着生物炭施加深度增加，生物炭消减土壤盐碱障碍的效果显著提升，进而促进大豆生长。相较于B0N0处理，在0~20cm土层中，B1H1N1处理土壤改良效果最优，其中，K+含量提高20.54%、Na+含量降低24.30%、钠吸附比降低46.68%、硝态氮含量提高26.61%；在20~40cm土层中，B1H2N1处理改良土壤理化性质效果最优，K+含量提高18.64%、Na+含量降低21.71%、钠吸附比降低32.85%、硝态氮含量提高30.77%。B1H2N1处理相较于B0N0处理，叶片氮含量提升21.54%、叶片氮养分积累量提高3361%、大豆粒质量提高3.33%、氮肥偏生产力提高28.37%。结合熵权TOPSIS模型综合评价结果，B1H2N1处理综合表现最佳，在有效调节苏打盐碱土盐分分布，为作物生长提供淡盐环境的同时可以活化深层土壤资源，提高氮肥利用率。

Abstract:

Soil salinization is a critical factor constraining the sustainable agricultural development of sodic saline soils in black soil regions. The effects of nitrogen reduction with biochar and its application depth on soda saline soil environment and soybean growth were investigated through a pot experiment. Two biochar application levels: 0t/hm2 (B0), 4.5t/hm2 (B1), two biochar application depths: 0~20cm (H1), 0~40cm (H2), and three nitrogen application levels: conventional nitrogen application (N0), 15% nitrogen reduction (N1), and 30% nitrogen reduction (N2) were set. The experimental results showed that under the condition of nitrogen reduction, the application of biochar could improve the saline soil environment and significantly increase the soybean yield. At the same time, with the increase of the depth of biochar application, the effect of biochar in reducing saline soil barriers was significantly increased, which in turn promoted the growth of soybean. Compared with B0N0 treatment, B1H1N1 treatment had the best soil improvement effect in 0~20cm soil layer, in which K+ content was increased by 20.54%, Na+ content was decreased by 24.30%, sodium adsorption ratio was decreased by 46.68%, and nitrate nitrogen was increased by 26.61%, and B1H2N1 treatment had the best effect of improving the soil physicochemical properties in 20~40cm soil layer, in which K+ content was increased by 18.64%, Na+ content was decreased by 21.71%, sodium adsorption ratio was decreased by 32.85%, and nitrate nitrogen was increased by 30.77%. The B1H2N1 treatment improved leaf N content by 21.54%, leaf N nutrient accumulation by 33.61%, soybean grain weight by 3.33%, and N fertilizer productive efficiency by 28.37% compared with the B0N0. Combined with the comprehensive evaluation results of entropy-weighted TOPSIS model, B1H2N1 treatment had the best comprehensive performance, which can activate the deep soil resources and improve the utilization rate of nitrogen fertilizer while effectively regulating the distribution of salinity in soda saline soil and providing a light-salt environment for crop growth.