应用^(15)N研究烤烟对秸秆N素的吸收利用

Study on absorption and utilization of nitrogen in flue-cured tobacco plant from rape straw fertilizer with ^(15)N

应用原子示踪法把15N标记在油菜秸秆内,再用标记后的油菜秸秆与硝酸铵不同比例配合施用,研究烤烟对菜籽秸秆N素的吸收利用规律。试验结果表明:秸秆中的15N在烟株体内利用率较低(0.088%~5.37%),在土壤中残留率较高(75.65%~85.06%)。不同生育时期烤烟对秸秆中15N的利用率为上部叶成熟期(中部叶成熟期(下部叶成熟期,不同部位对秸秆中15N利用率为叶(茎(根(顶,中部叶(上部叶(下部叶。试验中发现烟株各部位吸收秸秆15N百分数随着秸秆施用比例的增加而增加。试验还证明,25%秸秆肥处理15N利用率最高,土壤残留率最低,15N平衡差值最适中,有利于当季作物对秸秆15N的吸收,100%秸秆肥处理15N利用率最低,损失最少,土壤残留率最高,有利于土壤培肥。当秸秆肥用量比为25%时,所配施的硝酸铵基、追施各1/2可减少根、茎、顶对秸秆15N的吸收,增加根际土壤"AN"值,从而有利于叶片对秸秆15N的吸收。

A study on absorption and utilization of N in flue-curcd tobacco from rape straw fertilizer was conducted by isotopic tracing technol- ogy（The rape straw labeled by^15N and NH4NO3 was used as fertilized for tobacco） . The results showed： The ration of ^15N utilization in to- bacco plant from straw fertilizer was lower （0.088 % - 5.37 % ）, which was graded as at upper leaf maturity 〉 at middle leaf maturity 〉 at lower leaf maturity, leaves 〉 stalk 〉 roots 〉 tips, middle leaves 〉 upper leaves 〉 lower leaves. Meanwhile, the residual ration of ^15N in soil was higher （75.65 % -85.06 % ）. Adding the application rate of rape straw could increase the absorption percent of ^15N in different parts of tobacco plant. The results also said that, when the rate of application of rape straw fertilizer was 25 %, The utilization ration of ^15N in tobacco plant from straw fertilizer was the highest among all the treatments, but the residual ration of ^15N in soil was the lowest, and the balanced deviation of ^15N was the most appropriate, these are benefit to the utilization of ^15N in tobacco plant in those years. However, when the rate of application of rape straw fertilizer was 100 %, the utilization ration of ^15N in tobacco plant from straw fertilizer was the low- est and the wsidual ration of ^15N in soil was the highest among all treatments, these could enrich the soil. When the rate of application of rape straw fertilizer was 25 % , the treat of 1/2 NH4NO3 as basic fertilizer and 1/2 NH4NO3 as additional fertilizer could reduce the utilization of ^15N in roots ,stalk and tip, but add it in leaves and raise the ＂AN＂in soil.