氯化铵中氯的硝化抑制效应研究

通过盆栽试验 ,在种与不种作物条件下 ,研究了不同氮肥品种在土壤中的硝化作用 ,氯化铵中氯离子的硝化抑制效应及其对玉米营养和生长的影响。结果表明 ,不同氮肥品种在土壤中硝化作用大小为 :尿素 硫酸铵 氯化铵 ;氯化铵与尿素或硫酸铵配合施用能明显降低其氮素的硝化作用。氮素的硝化率与土壤含氯量呈显著负相关 ,氯化铵中氯能抑制氮素硝化作用 ,其硝化抑制效应强弱与氮肥品种和作物生长有关 ,氯对尿素的硝化抑制作用大于对硫酸铵的作用。不种作物时 ,氯化铵中氯的硝化抑制效应稳定且与双氰胺相当 ;种玉米促进了氮素的硝化作用。随着玉米生长及其对氯的吸收 ,氯的硝化抑制效应逐渐降低。硝化作用过强或过弱都不利于玉米苗期生长 ,玉米吸收NH4+-N与NO3--N需要一定比例。本试验条件下 ,玉米吸收土壤NH4+-N与NO3--N的最适比例为 1∶0.7～ 1∶1。合理配施氯化铵能调节土壤中NH4+-N与NO3--N的供给比例 ,提高玉米苗期生物产量。

Physiological regulation of potassium in sink-source distribution of tobacco

The effects of physiological regulations, such as the use of different growth regulators, and methods of top cutting management on potassium uptake and redistribution in sink and source in tobacco were studied under field conditions. The results indicated that no top cutting (endogenous auxin) or adding auxin at the top cutting stage (exogenous auxin) was conducive to mature leaf K content increase. Exogenous and endogenous auxines caused K redistribution from other parts of the plant to leaves. Exogenous auxin was more effective than endogenous for increasing mature leaf K content. Adding exogenous auxin to the tobacco plant twice is better than once during the growing period.