蔬菜作物钼效应及其临界值研究

THE EFFECT OF APPLYING MOLYBDENUM ON VEGETABLES AND ITS CRITICAL VALUES

通过盆栽试验，分析了在黄棕壤、灰正土和灰油砂土上施钼后，对１２种蔬菜作物产量、品质及植株含钼量的影响。结果表明：黄棕壤施钼可以显著地提高蔬菜作物的产量，并使大部分蔬菜的Ｖｃ增加；灰正土施钼，对开春蔬菜效果较好；灰油砂土施钼，对蔬菜基本没有增产效果，该土如在夏季施钼，易引起蔬菜作物减产，严重者可造成钼中毒。尽管不同种类蔬菜吸钼量存在差别，但测定结果表明，这种差别明显低于土壤供钼水平的差别，因此，不同种类蔬菜进行盆栽施钼效果的统一评价在一定程度上是可行的。根据ＣａｔｅＮｅｌｓｏｎ的方法作出的供试蔬菜作物施钼增产率和植株含钼量之间的散点图表明，蔬菜作物氮磷钾处理的植株含钼量和施钼与对照之差的植株含钼量对应于施钼增产极显著的临界值分别为０．３６ｍｇ／ｋｇ和０．５５ｍｇ／ｋｇ。

The plot biological experiment of applying Mo on vegetables has been conducted with yellow brown soil, calcareous alluvial loam soil and calcareous alluvial silty loam soil collected from Wuhan City. Application of Mo in the acid yellow brown soil could increase yields of vegetables and their Vc contents. Additional Mo on the calcareous alluvial loam soil was suitable to spring vegetables. Because of its high pH value and light texture, applying Mo in the calcareous alluvial silty loam soil would decrease the yield of some vegetables easily and cause Mo toxicity for cowpea in summer. Although the absorption of Mo was different for various vegetables, this difference was slighter than the difference of Mo supply in the experimental soils. Therefore, the evaluation of the standards of application molybdnum in these soils was feasible. According to Cate Nelson's method, a scattered point graph could be used to determine the critical values of plant Mo content which indicated that an application of Mo could result in significant increment of the yield of the vegetables or there was a serious Mo deficiency in the soil. The critical values in plant of NPK treatment and that of difference between NPKMo and NPK treatments were 0.36 mg/kg and 0.55 mg/kg, respectively.