不同形态氮肥对陇东烤烟产量形成的作用及其机理

Effects and Mechanisms of Different Nitrogen Fertilizers on the Yield Formation of the Flue-cured Tobacco in the East Gansu Province

针对陇东旱塬烤烟生产中存在的氮肥种类选择不合理引起的产量不高、品质下降等问题,于2009年在甘肃省庆阳市正宁县进行大田试验,研究不同形态氮肥硝铵磷(ANP)和尿素(UA)对烤烟产量形成的作用及其机理。结果表明:ANP处理显著促进了烤烟根系的生长发育,增强了烤烟根系活力,比UA处理具有更理想的根参数和更强的根系活力,移栽15 d后,ANP处理的总根长、表面积、根尖数和根系活力分别比UA处理的增加了63.4%,64.3%,54.3%和43.8%;ANP处理显著提高了根系和地上部干物质积累量,表现在收获时ANP处理的根系及地上部干物质积累量分别比UA处理的增加了15.87%和12.05%;烤烟移栽后短期内,ANP处理的土壤NO3--N含量明显高于UA处理的,且土壤NH4+-N含量明显低于UA处理的,移栽5 d后,ANP处理的土壤NO3--N含量比UA处理的增加了44.7%,NH4+-N含量比UA处理的降低了44.8%;ANP处理显著提高了烤烟产量和产值,分别比UA处理增加了16.8%和24.8%,纯收入增加了7 330元/hm2;尿素和硝铵磷施入土壤后短期内化学行为的不同,以及由此引起的根形态和吸收能力不同是引起烤烟产量和产值差异的主要原因。

Aimed at dealing with the serious problems brought about by irrational fertilization which detered the growth,yield and quality of flue-cured tobacco in Loess Plateau of east Gansu province,the present research had probed into the effects of different nitrogen fertilizers（ANP and UA） on yield formation of the flue-cured tobacco and its mechanisms,in 2009 in Zhengning county,Gansu.The results showed that：ANP significantly promoted the growth of roots and enhanced the activities of roots.Compared with UA treatment,ANP treatment had much better ideal root morphological parameters and root activities,15 days later after being transplanted,the roots were strong,exuberant,energetic,with the better index figures in total root length,superficial area,the sum of root tip and the vitality of root system,which were increased by 63.4%,64.3%,54.3% and 43.8% respectively;Compared with UA treatment,ANP treatment could significantly improve the dry matter accumulation of roots and aboveground part.120 days later after being transplanted,the dry matter accumulation of roots and aboveground part in ANP treatment were increased by 15.87% and 12.05%;Within a short period after being transplanted,the NO3^--N contents in soil of ANP treatment were significantly higher than those of UA treatment,but the NH4^＋-N contents in soil were lower than those of UA treatment.Compared with UA treatment,the NO3^--N contents in soil of ANP treatment were increased by 44.7%,the NH4^＋-N contents in soil of ANP treatment were reduced by 44.8% 5 days later after being transplanted;The application of ANP significantly improved the tobacco＇s yield and economic benefits.The yield,economic benefits and net income after the application of ANP were increased by 16.8%,24.8% and 7 330 yuan/hm^2.The productivity of flue-cured tobacco and the differences in production values could be ascribed to the difference of chemical behavior of UA and ANP after the application during the short period and the corresponding root morphology and absorption ability.