分层供水和表层施锌对玉米植株生长和锌吸收的影响

进行分层水分隔离盆栽试验,模拟田间不同层次土壤中水分含量分布不均条件,研究表层土壤施锌情况下,玉米植株生长和锌吸收以及根系在表层和底层土壤中的分配。结果表明,施锌明显促进了玉米地上部生长。在土壤表层水分充足时,施锌对植株增长效果较明显,有利于玉米利用土壤水分。缺锌条件下,改善土壤水分并未显著提高玉米生物量。表层土壤干旱时,上下层土壤中根系干物重之比减小,底层土壤中根系分布相对增加,当表层土壤水分增加时,根系在表层土壤中干物重显著增加,分布相对增多。施锌并没有影响根系在不同层次土壤中的分配。表层土壤水分对苗期玉米植株锌吸收总量有显著影响,干旱条件下,玉米植株锌吸收总量下降;底层土壤水分供应状况对玉米锌浓度影响不大,但植株中锌向地上部运转增加。尽管施锌没有提高生长早期玉米根系生长和对底层土壤水分的利用,但本研究表明缺锌旱地土壤上如通过灌溉等措施增加了耕层土壤水分,应该注意施用锌肥,否则严重影响玉米生物量和玉米对土壤水分的利用效率。

Maize plant growth,root biomass distribution,and zinc uptake as affected by Zn application and different water conditions in soil layers

The early crop growth and development are always subjected to soil moisture deficits and Zn deficiency concurrently in Northern China.The experiment with splitting vertically layer culture systems was conducted to examine maize plant biomass and Zn uptake as affected by Zn application in topsoil and different water treatments in both soil layers.Shoot growth and Zn uptake were significantly enhanced by Zn application.Under adequate soil moisture supply in upper soil layer or whole soil layers,the increase of plant growth and Zn uptake due to Zn application was more remarkable than that under drying conditions.The distribution plant roots in different soil layers was not influenced by Zn application in topsoil but by soil water supply.Root biomass in the upper soil layer increased with adequate water supply in upper soil layer,while a larger proportion of root biomass tended to distribute in lower depth when upper soil layer was dry.In the zinc deficient cumulic cinnamon soil of Northern China often encountered by dry climate,although the storing water in lower soil depth could not promote early maize plant to take up more Zn from soils,our research gave a clear point that soil water in upper soil layer was important to enhance the influence of Zn application in topsoil on early maize growth.Moreover,Zn was recommended to apply if irrigated adequate water in soil layer so as to promote plant water use.