Andy's Advice on Herbicide

PRE PLANT SPRAY AND RELEASE

Prior to planting, it is imperative that all existing vegetation is sprayed. Especially if we are looking at such things as brush weed, for example gorse (ulex spp), and broom (Cyrstus spp).

Once the vegetation is sprayed, it can then be crushed prior to planting. These operations have a several fold advantage.

By kill spraying large vegetation several months prior to planting, this stops transpiration, and therefore increases soil moisture. Thus allowing not only a fertile bed, but also a moist bed for the trees to be planted into in the coming winter. Once the vegetation has had a chance to cure (completely dead), the area can then be roller crushed.

This has the advantage of not only improving planting access, but it forms a mulch on the ground trapping all moisture, and if the mulch is deep enough it will inhibit future weed regrowth, thus eliminating the need for a more expensive release spray. A pre plant spray is always cheaper than a release spray, and if managed correctly can be used very effectively to enhance tree growth, and reduce overall costs

RELEASE SPRAYING

I have developed several herbicide formulations capable of being sprayed over plantation trees, killing all existing weed competition, and leaving the trees unharmed. This can be achieved at any age, and any state of growth. 

However it has to be mentioned, that the older the vegetation that needs to be controlled, the more expensive the herbicide formulation. That is why it is imperative to combine this type of release with an initial pre plant spray, so that we are only dealing with juvenile plants when considering a release formulation, especially when we are considering dicotyledon plants, such as gorse (ulex spp), and broom (cytisus spp).

Tree growth is directly proportional to the amount of bare earth around the tree. This is exemplified in areas where drought is quite prevalent, or if rain fall seldom exceeds 1500 mls per annum.

When considering releasing trees from grass, a one square metre spot is all that is required. In some cases however, if the spot is increased to 2 sq. metres tree growth will be enhanced accordingly. When we are considering brush weeds however, a 2 sq metre spot is the absolute minimum that should be considered because, brush weeds are far more aggressive when transpiring moisture from the soil. Examples of this are given in a table below

 .

Bare earth around tree Tree increment after one year as a %
No spray 0%
1 sq metre 89%
2 sq metres 211%
100% Sprayed 318%

As can be seen a complete aerial release in the first year dramatically enhances initial tree growth. The following photographs show  aerial release in the background, with a spot spray in the foreground. One year after planting the trees in the aerial release are doing fine, while all the trees in the foreground which were spot sprayed, have perished due to drought stress, and weed competition

                            
               Photo taken 6 months after spraying                          Background: Aerial release after planting. 
                                                                                Foreground: Spot sprayed after planting. Broom regrowth has killed trees.


               Photo taken after one growing seasons               Trees which were aerially released are doing fine while trees in the
                                                                                                                      foreground have been smothered.

It is more economical to aerial release when the competing vegetation is still in the cotyledon stage. This is a "prevention".

 

 

 

 

 

 

However a "cure" opperation can also be undertaken, but is more costly. The above photo shows the result of an aerial release operation which is showing P.radiata being released from gorse (ulex).

HERBICIDE FORMULATIONS

When considering appropriate herbicide formulation there are several factors to consider, namely, mode of action, that is, it is to be taken up through the roots, or the foliage. The state of the vegetation, the season of the year, the dryness of the soil and weather conditions.

When a manager plans an application, seldom can one active ingredient cater for all purposes. The exception to this of course, is when we are controlling a mono cotyledon such as grass, in moist soil conditions. This is where a root absorbed herbicide is the only thing that is required. However, as your soil conditions dry out, the mode of action needs to be changed from a root absorbed formulation, to a foliar absorbed formulation, and this is where the surfactants, and other active ingredient herbicides need to be considered.

 

  

These unique nozzles have been designed by the owner of Coast to Coast Helicopters, Mr. Andy Brown. They give a very uniform droplet distribution. These large VMD droplets do not drift. The property of the released droplet enables it to shatter on impact. This means that these large droplets will not drift, but still give maximum coverage of the sprayed plant.

 

    

Amuri Helicopters Ltd have developed a spraying system that reduces fines, giving an even spray pattern with even vortices


    

Broom before and after The aerial release of P.Radiata
The photo to the left was taken before Broom infestation of P.Radiata prior to aerial release, The photo to the right was taken one month after application.