低锌旱地施锌方式对小麦产量和锌利用的影响

西北地区是我国典型的旱地低锌区。本文选择黄土高原中部两个典型地点，通过田间试验，在两个施氮水平下，研究了不施锌、 土施锌、 叶喷锌和土施+叶喷锌4种方式对冬小麦产量、 锌的吸收和累积以及锌肥利用效率的影响。结果表明，不同施锌方式对小麦产量均无显著影响，但均提高了小麦子粒锌含量，提高幅度因施锌方式而异。与不施锌相比，叶喷和土施+叶喷锌肥可使小麦子粒锌含量提高40%左右，平均达到 40 mg/kg；单独土施锌肥虽使土壤有效锌提高3倍左右，但子粒锌含量无显著变化。叶喷锌肥的锌利用效率远高于土施和土施+叶喷处理，每公顷喷施1 kg锌可使小麦子粒锌含量提高6.70~13.04 mg/kg；子粒锌利用率为6.02%~9.40%， 达到土施锌肥的80倍左右；总锌利用率为19.78%~30.91%，是土施锌肥的132~221倍。施氮水平对小麦产量及锌肥利用效率均无显著影响。可见，在旱地低锌区，与土施锌相比，叶喷是更加经济有效、 环境友好的锌肥施用方式，是提高小麦锌营养品质切实可行的措施。

Effect of Zn application methods on wheat grain yield and Zn utilization in Zn-deficient soils of dryland

Soil Zn deficiency and drought are serious stress factors limiting the Zn nutrition of crops in northwest China. Field experiments were conducted to study the effects of soil application, foliar application and soil+foliar application of Zn on yield, Zn contents and accumulation in grain, and Zn use efficiency of winter wheat grown under two N rates at two locations in the middle part of Loess Plateau. Results show that Zn application does not increase the grain yield of winter wheat, but can increase the grain Zn contents. The increases are varied with the Zn application methods, the grain Zn contents are increased by about 40%, up to 40 mg/kg for foliar application and soil+foliar application, not significant with soil application, although the soil DTPA-Zn is triply increased. Zinc use efficiency of the foliar applied Zn is higher than those of the soil and soil+foliar applied Zn. Each one kg/ha foliar applied Zn is observed to be able to increase the grain Zn content by 6.70-13.04 mg/kg. The grain Zn utilization and total Zn utilization efficiency are respectively 6.02%-9.40% and 19.78%-30.91% for the foliar applied Zn, which are correspondingly 80 and 132-221 times more than those for the soil applied Zn. Nitrogen rates have no effect on the yield and Zn utilization. Therefore, the foliar application of Zn is more cost effective and environmental friendly than the soil application, and is one of the important practices to improve grain Zn concentration on Zn-deficient soils in dryland areas of northwestern China.