Large areas of arable land across the world have soils known to be zinc deficient.
It has been recognised that the use of increased amounts of high quality phosphorus fertilisers along with new, high yielding varieties of rice, wheat and other crops, often contributes to this level of zinc deficiency, especially where the existing plant-available levels of zinc in the soil is marginal.
In South and East Asia, for instance, rice tends to be the crop most affected by zinc deficiency, due to the effect of flooding on zinc availability. These too are the areas of heavy population with high dependence on rice as a staple food, so there is real imperative to address this issue.
China currently has the largest population in the world, but with only has one third of the world average ‘per capita’ area of land available to it for cultivation, faces compounding challenges.With land being so scarce, it is essential that crop productivity is notlost through zinc deficiency.It is estimated that half of China’sfarmland is zinc deficient and requires zinc fertilisation or remediation, especially for corn and rice.
In India and Pakistan large areas of zinc-deficient alluvial soils exist, generally it is believed,because of the sequential rice-wheat cropping regime that is undertaken on a large scale to optimise food production. It has been estimated that approximately one half of the soils from all ofIndia’s main agricultural areas are deficient in zinc. This could represent as much as 80 million hectares of arable soil.
In The Philippines, 8 million hectares of wetland rice are estimated to be zinc-deficient.
In Indonesia rice accounts for more than half of the energy consumed through food intake by more than 100 million people. Rice cultivation covers approximately 10 million hectares of land throughout the archipelago. The supply and control of water is crucial to the rice cropping system, high-yield varieties are being experimented with, and dryland cultivation as well as swamp and tidal cultivation systems co-exist. Zinc deficiency remains an issue for the populace and in 2011 zinc supplements were introduced into the diets of children and pregnant women.
In Australia, 8 million hectares of zinc deficient land exists in one area alone on the border between South Australia and Victoria. Extensive areas exist in other parts of the country, and notably Western Australia where vast cereal crop environments are established.
As stated, this is a global issue with the same problem with zinc deficiency existing in soils in every growing and cropping environment across the world. No country, region, or farm is immune.
Once zinc-deficient soils have been identified however, the problem is easily and cost-effectively rectified by the application of zinc fertilisers, either to the seed or by foliar spray directly onto the crop.