【摘要】 本研究借助¹⁵N同位素示踪技术,致力于探索植株对肥料氮的利用效率。分别设置了生物炭调控（M1）、生物炭与秸秆联合调控（M2）、秸秆调控（M3）。分析了土壤中标记氮肥的含量变化、植株氮素的累积以及各器官氮素来源,进而阐述了不同覆盖调控下植株对肥料氮的吸收、分配以及利用效果。结果如下:1)秸秆的保温持水能力和生物炭的理化特性显著提升了土壤中无机氮的含量水平; 2)土壤覆盖调控作用有效地提升了植株氮素累积效果,随着覆盖量的增加,来源于氮肥的氮素含量显著提升,并且¹⁵N利用效率从大到小依次表现为籽粒>茎秆+叶鞘>根系>叶片>苞叶+穗轴; 3)生物炭调控作用有效地促进了植株根系对标记氮肥的吸收效果,生物炭与秸秆的联合调控、秸秆覆盖分别促进了籽粒、茎秆+叶鞘对标记氮肥的积累效果。该研究结果可为合理高效开发农业水土资源,科学指导农业肥料使用提供理论参考。更多还原

【Abstract】 [Background]The utilization efficiency of nitrogen fertilizer indicates the ability of crops to absorb nitrogen from soil and fertilizer. At the same time,nitrogen absorption and accumulation are the basis of crop yield formation. It is helpful to find out the relationship between the increase of crop yield and the efficient use of nutrients by investigating the accumulation of nitrogen uptake by crops. With a view to investigating the destination of nitrogen fertilizer and its use efficiency in plants under different farming modes,this paper explores the nitrogen use efficiency of plans employing the ¹⁵N isotopic tracer technique. [Methods]Three mulching modes,namely,biochar regulation（ M1）,combined regulation of biochar and straw（ M2） and straw regulation（ M3） were set up in the course of experiment,each containing three gradients,namely,6 t/hm²（F1）,12 t/hm²（ F2） and 18 t/hm²（ F3）. The adsorption,distribution and use effect of nitrogen fertilizer in summer maize under different mulching control measures were investigated by analyzing the content change of marked nitrogen fertilizer in soil,the accumulation of nitrogen in plants and the source of nitrogen in each organ according to the field experiment. [Results]1) The heat-retaining and water-holding capacity of straw and the physical and chemical properties of biochar significantly increased the content of inorganic nitrogen in soil. At the shooting stage,the average content of inorganic nitrogen in 0-80 cm soil layer under the M2F1 treatment condition was 11. 71 and20. 25 mg/kg and higher than that under the M1FI and M3F1 conditions respectively. At the maturation stage,this average value under the M2F1 treatment condition was also remarkably higher than that under the M1F1 and M3F1 conditions. 2) Soil mulching regulation was effective in enhancing the accumulation effect of nitrogen in plants. The increase of mulching was accompanied by the marked rise of nitrogen content coming from nitrogen fertilizer. As shown by the analysis of the adsorption of labeled nitrogen by each organ,the results of ¹⁵N use efficiency in organs were as follows: Grain > Stem + leaf sheath >Root > Blade > Loquat + cob. The combined regulation of straw and biochar guaranteed the strongest nitrogen adsorption effect. 3) The results from Pearson and related analysis demonstrated that the biochar regulation effectively promoted the adsorption of labeled nitrogen fertilizer by root system,the combined regulation of biochar and straw facilitated the regulating effect of grain on marked nitrogen fertilizer and straw boosted the accumulation of marked nitrogen fertilizer in stalk + sheath. [Conclusions]The research may provide theoretical reference and technical support for the reasonable and effective development of agricultural water and soil resources and scientific guidance on agricultural fertilizer usage.更多还原