Purpose

The aims of this work were (i) to find a soil indicator to predict durum wheat yield response to Zn fertilization, (ii) to compare the effect of various Zn fertilization strategies on wheat yield and Zn biofortification in calcareous Vertisols of southern Spain, and (iii) to assess the effect of these Zn fertilization strategies on crop P uptake (durum and bread wheat).

Methods

Different Zn fertilization strategies, soil application (0.3–10 kg ha⁻¹) and foliar spraying (two rates, different growth stages), were tested in wheat crops under field conditions in the period 2012–2019.

Results

A simple soil indicator failed to predict durum wheat response to Zn fertilization. Only one of the combinations tested increased wheat yield in the 11 field experiments carried out. Zinc foliar spraying (1.28 kg ha⁻¹) was effective for wheat biofortification when applied at early booting (durum wheat) or flowering, and also when splitting this application between stem elongation and flowering stages (bread wheat). The foliar treatments produced the highest zinc use efficiencies (6–19%) and soil applications the lowest (0.2–1.3%). Moreover, foliar treatments increased grain Zn concentrations by 12–51% while soil application increased such concentrations by only 4–13%. None of the Zn fertilization strategies altered P uptake.

Conclusion

No yield increase in wheat is expected from Zn fertilization for the application methods and rates used here and the soils studied (calcareous Vertisols under Mediterranean climate). However, foliar applications at and after early booting stage are promising for durum and bread wheat biofortification.

中文翻译：

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西班牙南部钙石灰石生长的小麦锌生物强化策略：施用方法和施用率

目的

这项工作的目的是（i）寻找一种土壤指标来预测硬粒小麦产量对锌肥的响应，（ii）比较西班牙南部钙质Vertisol中各种锌肥策略对小麦产量和锌生物强化的影响，以及（iii）评估这些锌肥策略对作物磷吸收的影响（硬粒小麦和面包小麦）。

方法

在2012-2019年期间，在田间条件下对小麦作物测试了不同的锌施肥策略，土壤施用量（0.3-10 kg ha ^-1）和叶面喷洒（两种速率，不同的生长期）。

结果

一个简单的土壤指标无法预测硬粒小麦对锌肥的反应。在进行的11个田间试验中，只有一种测试的组合提高了小麦产量。叶面喷洒锌粉（1.28 kg ha ^-1）在早早启动（硬粒小麦）或开花时使用，以及在茎伸长和开花期（面包小麦）中分开使用时，对小麦的生物强化都是有效的。叶面处理的锌使用效率最高（6–19％），而土壤处理的锌使用效率最低（0.2–1.3％）。此外，叶面处理使谷物中的锌浓度增加了12–51％，而土壤施用仅使这种浓度增加了4–13％。锌的施肥策略都没有改变磷的吸收。

结论

锌肥的施用方法和施用量以及所研究的土壤（地中海气候下的钙质Vertisols）预计不会增加锌的小麦产量。然而，在硬粒小麦和面包小麦的生物强化过程中​​，在启动初期及之后的叶面应用前景广阔。