Debate on the sustainability of glyphosate

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There has been much discussion recently on the sustainability of glyphosate, writes Wendy Fearon.

A decision was to be made at the end of June regarding licence renewal but with Brexit dominating the news Europe has decided to give glyphosate an eighteen month extension.

It is important to note that labels must be followed and best practice guidelines adhered to.

The three proposals put forward which are to minimise use in public areas, banning tallow amine formulations and pre-harvest use have now been devolved to member states.

It will now be up to each individual state whether or not they decide to implement the above mentioned.

Some manufacturing companies have already decided to cease making tallow amine formulations.

Pre Harvest Glyphosate

Ground conditions have deteriorated in the last few weeks with the thundery showers yet winter barley crops are ripening well and thoughts will now turn to grain quality, moisture levels, and ease of harvesting.

This year in particular grasses and other weeds are a real problem in many fields. Pre harvest application of glyphosate is an essential tool to improve the efficiency of harvesting, giving a range of benefits:

Harvest management

-all green tissue removed – ripens any green stems, leaves and pickles so allowing cutting to start earlier in the day and continue for longer

-no green pickles reducing overall grain moisture and drying costs

-less grain lost over straw walkers caused by green material during threshing

-faster straw clearance reduces length of weather window required

-limits sprouting in laid crops

Scutch and general weed control

-the most effective time to control scutch in tillage ground

-desiccates any other green grass and broad-leaved weeds present, facilitating lower grain moisture, faster harvesting and sooner baling of straw

Note however, do not use glyphosate on any crops where seed may be saved for re-sowing.

Independent trials carried out over a number of years in GB looking at the effect of using Roundup in various replicated treatments consistently show moisture contents being reduced by 2.0-2.5% at harvest compared to plots where no treatment is applied.

With a wide range of glyphosate products available, which offers the best performance in the field, and best value for money?

First off, it is not the price per drum that should be compared.

With different formulation types having different strengths of active per litre and therefore different rates of use, it is the price per acre treated that should be compared, and what level of performance is being obtained from each.

Glyphosate itself is not very soluble therefore it depends very much on the salts and wetter’s to enhance its performance.

Tallow amine products de-wax the leaf surface and cause cell damage, whereas the ROUNDUP ENERGY wetter does not damage the leaf surface, so the uptake of glyphosate into the leaf is much more effective than with the ETA product, and the level of long-term kill achieved from ENERGY is significantly greater.

The potassium salt in Roundup Energy is also taken up significantly faster than the isopropylamine salt; as a result ENERGY is rainfast within 1 hour of application and cultivation can commence as soon as two days after application whereas the IPA glyphosate products need a minimum of six hours to be rainfast and five days minimum before cultivating.

Application should be made once the grain moisture gets down to 30% or below, ideally 10-14 days (and not less than 7 days) before cutting.

An easy and reliable test to estimate this 30% moisture level is to press the thumbnail into a number of grains; if the indentation holds on all the grains the crop is ready for spraying.