FOLIAR PHOSPHATE FOR POTATOES
Phosphorus is easily tied up in the soil and becomes less available when soils are either very wet or dry.
Uptake is less when soil temperatures are low.
Optimum soil temperature for potato growth is 15-20C. Maximum rate of plant growth usually occurs between 30 and 75 days after emergence and demand for P is greatest during the period 30-45 days after emergence with a daily uptake of 1.4k P per hectare
Poor rooting of plants reduces the uptake of P
P is particularly important during the reproductive development of plants, which, for potatoes starts before a good root system has developed and at a time when soil temperatures may still be fairly low, thus limiting uptake of P.
Application of phosphate during tuber initiation helps the plant to set more tubers and then to carry these tubers to maturity.
As root growth and soil temperatures increase the plant is able to absorb more P, however since early setting tubers are the ones which contribute most to yield some yield will be lost if P is not adequate during the early part of initiation
Final weight of individual tubers has been shown to be related to cell diameter, since any deficiency of P affects the cell structure and expansion
The plants need for Phosphorus is
greatest between 30 & 60 days after emergence but
Phosphorus is easily tied up and less
available in very wet, dry, cold or compacted soils. If a
phosphorus deficiency persists for any length of time during
this early growing period the plant will be unable to compensate
later, even if phosphorus becomes freely available.Phosphorus
application during tuber initiation alsohelps the plant to set
As root growth develops and soil temperatures increase, the plant is able to absorb more P. But when soil temperatures are still relatively cold and plants are struggling in poor conditions the need for foliar applied P is vital.
Fos 4-20-0 w/w
Fos + Mg 4-20-0 2Mg w/w