Berry Gardens is Britain’s premier soft and stone fruit supplier and is a cooperative owned by its grower members. They support growers in every aspect of fruit production from variety selection and planting through to packaging and marketing. Regular meetings are held where growers learn about new technological developments and two meetings in March 2017 at Stansted and Birmingham (UK) focussed on substrates and crop nutrition.
Beginning by explaining the fundamental importance of iron in plants (and all life forms) Dick explored some of the chemistry involved. Iron is essential to plants because of its ability to readily undergo RedOx reactions thereby removing and donating electrons; this in turn powers many metabolic pathways and the production of life-giving chlorophyll. Paradoxically the same chemistry, influenced by pH, is the reason for crops suffering from iron deficiency. Iron, or more precisely the ferric (Fe3+) ion is very sensitive to pH and becomes insoluble (unavailable to plants) under alkaline conditions, hence the term "lime-induced chlorosis".
Dick then explained the elegant mechanisms that plants roots have evolved to absorb iron from their environment and considered the usefulness various iron compounds as fertilizers concluding that only synthetic iron chelates were truly effective. He continued by reviewing the main types of iron chelate namely EDTA, DTPA and EDDHA, each having specific characteristics to suit differing circumstances. Careful selection enables the most effective and economical correction of yield sapping iron deficiency.
The presentation concluded by Dick explaining the importance of all the trace elements - not just the iron - in feed solutions being fully chelated (boron and molybdenum excepted). Otherwise there is a relentless tendency for 'preferential chelation' reactions to take place. Here the iron chelate releases iron in favour of linking with copper, manganese and zinc and the iron is then lost through precipitation, as insoluble phosphates and hydroxides. This is often seen with cheap water soluble fertilizers where to save cost the trace elements are unchelated or partially chelated.
Solufeed Ltd who introduced probably the very first speciality fertilizer ("Solufeed F") in 1947 now have a wide range of water soluble fertilizers (with fully chelated trace elements), a complete portfolio of complimentary iron chelates and many other products for the progressive fruit grower. All with the enviable Solufeed technical and commercial support.
Technical Essentials - Iron and the special role of EDDHA in protected crops
Blog - New Strawberry Guide.