Agronomy Advice

Maize crops need zinc

By: Mark Tucker

Almost a third of all maize soil samples and over half maize tissue samples analysed show potential zinc deficiency highlighting this key micronutrient.

Forage maize needs zinc
Forage maize needs zinc
Zinc is a key micronutrient for maize

Zinc plays a vital role in many functions within the plant. One of the well-documented functions of Zn is its role in protein synthesis and its contribution to the structural integrity of a number of proteins. Zn deficiency results in a severe decline in protein biosynthesis. Up to 10% of the proteins in biological systems need Zn for their proper functioning and for the maintenance of their structural integrity. It is therefore not surprising that plants show a high susceptibility to low concentrations of Zn in tissues.

Other important functions of Zn in plant cells are: Structural and functional integrity of cell membranes, Detoxification of reactive oxygen species (ROS), Photo-oxidation and light damage (destruction of chorolphyll), Synthesis and protection of IAA (hormone that controls plant growth and development), Reducing cadmium accumulation in plants. 

The structural integrity of cell membranes is important also for protecting plants against pathogenic infections. Exudates from ‘leaky’ cells create an environment ideal for growth and invasion of root cells by fungi and bacteria. 

The most common symptoms of zinc deficiency in maize include the development of whitish or yellowish stripes parallel to the midrib on the young leaves and stunting appearances with shortened internodes. Necrotic spots and reddish colour may develop on leaves as the deficiency develops.

YaraVita Zintrac gave an 8% yield increase

A Yara trial in 2014 was conducted on Maize destined for an AD plant with a value of £33/t at 32% DM. YaraVita Zintrac was applied at 1 l/ha at the three leaf stage. The control plots were at 32 ppm Zinc, so just above the guideline level of 30 ppm. At harvest the YaraVita Zintrac gave an 8% yield increase, which was equivalent to a 3.92 t/ha yield increase, valued at £129.36 / ha.

Phosphate is another nutrient which often restricts maize yields. Independent research has shown that P deficient maize plants growing in cold and/or acid soils utilise phosphate that is applied to the leaf much better than those plants already receiving adequate P from the soil. The rate of uptake by leaves of the deficient plants was twice that of the control plants which had the correct fertilizer applied, much more P was translocated from the leaf - particularly to the roots which maximises early root development.

Crop Boost increased yield by over 20%

In a recent poor year for growing maize, farmers estimated that YaraVita Crop Boost used proactively at the correct timing improved crop yield by over 20%. In 2010 two farm trials conducted in a good maize growing year, raised starch analysis by an average of 20.1% following one spray at the 4 to 6 leaf stage.

Other trace element deficiencies can be seen in maize, especially where little or no organic manures are applied. Key ones to look for would be Boron, Copper and Manganese. A foliar analysis should be carried out if unusual symptoms appear.

Read about improving nutrient efficiency

Grass and forage agronomy and fertiliser advice
Grass and forage agronomy and fertiliser advice

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