Magnesium plays a central role in photosynthesis, as it is present in the center of each chlorophyll molecule. It is also involved in various key steps of sugar and protein production as well as the transport of carbohydrates from the leaves to the tubers.
Magnesium and relative yield
Severe magnesium deficiency can reduce yields by up to 15%. Regular use of magnesium on an annual basis has provided yield increases of 1 to 10% in trials. Adequate magnesium is needed during tuber bulking. If dry soil conditions restrict uptake, then foliar sprays can be very effective.
Magnesium and yield
Trials in UK also show the effect magnesium has on yield.
Magnesium and specific gravity
Low levels of magnesium will reduce the starch content of tubers and protein levels that affect the taste of the cooked potato. Trials in Australia confirm the positive benefits of magnesium on specific gravity.
Magnesium and dry matter
Magnesium also benefits tuber dry matter, as trials in Holland show.
Magnesium and tuber discoloration
Low magnesium levels can increase susceptibility to enzymatic discoloration, as studies in USA show.
General guidelines for magnesium application
Uptake of magnesium is dependent upon the cation exchange capacity of the soil and its balance with the other cations, especially potassium. High concentrations of potassium in the soil can induce magnesium deficiency. In such cases, foliar applications of magnesium are beneficial.
|Magnesium at potato growth stages
||Chlorophyll production, growth and enzymatic activity
||Photosynthesis and enzymatic activity
||Photosynthesis, carbohydrate transport from the leaves to the tubers, and enzymatic activity