Corn, rice and wheat, three of the world’s most important cereal crops, are all affected by zinc deficiency. Clearly, everything that grows in zinc depleted soils will suffer, but of these three major crops, rice will be looked at a little more closely.
Corn (known as maize in many parts of the world) is the crop species which is understood to be most susceptible to zinc deficiency. Corn generally accounts for the highest use of zinc fertiliser per hectare, more than any other crop. With the increase in demand for corn in addition to human food supply, for livestock feed and biofuel production the mitigation of zinc deficiency in this crop is going to remain an important crop nutrition priority.
Wheat is less sensitive than corn, but it is still severely affected by zinc deficiency in many parts of the world, especially the larger broad-scale farming enterprises in Australia, North America, Europe and the countries of the former USSR. Low available zinc concentrations in chalky soils, with a relatively high phosphorus status tends to be the most widely found cause of zinc deficiency in wheat.
Rice is known to be crucially effected by zinc deficiency, and probably attributed to the way in which it is farmed. Approximately two-thirds of the crop is currently produced in flooded paddy systems and while this has many advantages, it is relatively inefficient in its use of water. Alternative, more water efficient rice growing systems are however being developed in some countries. It is known that flooding the soil reduces the availability of zinc tothe crop, whilst increasing the concentrations of soluble phosphorus which contributes to zinc deficiency problems. It has been recorded that possibly as much as half of the paddy rice soils are affected by zinc deficiency. When you consider how important this crop is for Asia alone, it could actually involve up to 35 million hectares of its rice producing land. Even though many areas of lowland paddy rice production are being replaced by more water-efficient production systems, it appears that these new systems could also be susceptible to zinc deficiency, still requiring the application of zinc fertilisers.
- zinc deficiency is the most widespread micro-nutrient disorder
- zinc deficiency has actually increased with the introduction
of modern crop varieties and crop intensification strategies