活化腐植酸–尿素施用对小麦–玉米轮作土壤氮肥利用率及其控制因素的影响

Effect of activated humic acid-urea on nitrogen use efficiency and its driving factors under wheat-maize rotation system

  • 摘要: 腐植酸尿素是近年来的一种新型有机无机复合肥料, 其增产效应显著, 但是在小麦玉米轮作中该肥料的利用率和环境调控因素尚不清楚。本研究通过田间定位与室内培养试验, 以不施肥处理(Control)和单施尿素处理(Urea)为对照, 研究腐植酸尿素直接掺混处理(U+HA1)、腐植酸尿素活化处理(U+HA2)和腐植酸尿素活化催化处理(U+HA3)对小麦和玉米生长、土壤理化性质、氮肥利用率和土壤氮转化及土壤脲酶含量的影响。研究结果表明: 活化腐植酸尿素处理的小麦、玉米籽粒产量分别较Urea处理增产15%~28%和8%~10%。活化腐植酸尿素施用显著地降低土壤容重、pH和土壤颗粒粒径的中位粒径, 提高了土壤的比表面积、电导率、有机碳含量和矿质态氮含量。小麦季活化腐植酸尿素处理下氮肥回收利用率较Urea处理显著增加, 增加幅度为37%~91%, 玉米季的增加幅度为78%~93%。活化腐植酸尿素处理下小麦和玉米的氮肥农艺利用率和偏生产力均较Urea处理高。此外, 回归分析表明活化腐植酸尿素的氮肥当季回收利用率随土壤硝化比率、有机氮的矿化量及脲酶含量的增加而降低, 而随土壤颗粒比表面积的增大而提高。本研究结果明确了腐植酸尿素活化处理对小麦、玉米的增产效果较好, 可改善土壤理化性质, 其中腐植酸尿素活化催化处理(U+HA3)的效果最好。研究结果为活化腐植酸尿素肥料的深入研发与推广提供基础资料。

     

    Abstract: Humic acid-urea is an innovated fertilizer used widely in agricultural production in recent years. However, understanding on nutrient use efficiency of humic acid-urea under wheat-maize rotation system and its driving factors has so far been limited. In this study, the effects of activated humic acid-urea on wheat and maize growth, soil physicochemical properties, nitrogen use efficiency, soil nitrogen forms and contents were investigated in both field and incubation experiments. Three activated humic acid-urea treatments used in the experiments included mixed humic acid and urea (U+HA1), activated humic acid-urea (U+HA2) and activated and catalyzed humic acid-urea (U+HA3). For comparison with those urea treatments, no fertilizer application treatment (Control) and single urea application (Urea) were set up. Wheat and maize grain yields in U+HA2 and U+HA3 treatments were enhanced respectively by 15%–28% and 8%–10%, compared with Urea treatment. The application of activated humic acid-urea not only significantly reduced soil bulk density, pH and center diameter of soil granule, but also significantly increased soil specific surface area, electrical conductivity, organic carbon concentration and mineral nitrogen content. In wheat season, nitrogen recovery efficiencies with activated humic acid-urea treatments were markedly higher than that of Urea treatment. The rate of increase for wheat was 37%–91% and that for maize was 78%–93%. The trends in nitrogen agronomic efficiency and nitrogen partial productivity were then same for activated humic acid-urea treatments under wheat-maize rotation system. In addition, regression analysis showed that nitrogen recovery efficiency decreased with increasing soil nitrification, soil organic nitrogen mineralization and soil urease activity. However, it increased with increasing soil specific surface area. In the study, U+HA3 was the best treatment for crop yield, soil physicochemical properties, etc., which was therefore recommended for application in agricultural production. The results of the study provided the basis for the development and promotion of activated humic acid-urea used in agriculture.

     

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