生物炭与化肥氮配施对土壤氮素及烤烟利用的影响

  目的  为探讨施用生物炭对土壤氮素及烤烟对氮素利用的影响。  方法  2015-2016年在河南省方城县金叶园大田条件下，设置了添加生物炭后不同氮水平，研究对土壤硝态氮、铵态氮、碱解氮以及烤烟对氮素吸收积累的影响。  结果  在烟株生育期内，添加生物炭后显著提高了土壤硝态氮含量。2015年硝态氮含量最高达到铵态氮含量的15.72倍，2016年为34.56倍；2016年提高无机氮含量达6.70%~52.47%；添加生物炭对土壤碱解氮含量在烤烟生长前期有一定的提高作用，而在烟株打顶后有效降低了其含量，有利于顺应土壤供氮与烤烟需要适时落黄成熟规律。施加生物炭后，烤烟氮素积累速率前期较高，后期下降。连续施用2年后，氮素利用率可高达49.14%和47.62%。  结论  生物炭与氮肥配施，提高了土壤氮素含量，增施生物炭减少15%化肥氮仍能提高烤烟氮素利用，且连续施用对氮素固持和提高烤烟利用率效果明显。 

Effects of mined appli cation of biochar and nitrogen fertilizer on effective nitrogen in soil and nitrogen accumulation in flue-cured tobacco

  Objective  This paper explores effect of biochar application on effective nitrogen in soil and nitrogen accumulation in fluecured tobacco.  Methods  In 2015-2016, different nitrogen levels after biochar application were set up in field of Fangcheng Gold Leaf Garden in Henan province, and effects of nitrate nitrogen, ammonium nitrogen, alkali-nitrogen and effect of flue-cured tobacco on nitrogen uptake and accumulation were studied.  Results  In the whole growth period of tobacco plant, content of nitrate nitrogen increased after biochar application. In 2015, the highest nitrate content was 15.72 times of ammonium nitrogen, 34.56 times in 2016;and inorganic nitrogen content in 2016 was increased by 6.7%~52.47%. Addition of biochar can improve content of available nitrogen in early growth stage of flue-cured tobacco, but it effectively reduces the content of available nitrogen in maturity period, making it easy to adapt to soil nitrogen supply and requirement of flue-cured tobacco maturation. After biochar application, the nitrogen accumulation rate was higher in early stage and decreased in maturity period. After two years of continuous application, nitrogen utilization can be as high as 49.14% and 47.62%.  Conclusion  The application of nitrogen fertilizer with biochar could promote content of available form nitrogen in soil, and increase application of biochar and reduce application of nitrogen fertilizer by 15% and its continuous application could significantly improve nitrogen retention and utilization efficiency.