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Category: Cropping

Using fertiliser to increase hay & silage yields



Nitrogen fertiliser can be used to boost pasture growth. For nitrogen applications to be successful, the grass must be in a growing state. If the grass is not growing, the plants will not take up the nutrient. The response that can be obtained from applying nitrogen depends on numerous factors such as:


  • soil fertility      
  • soil temperature      
  • type of plants      
  • soil moisture      
  • sunlight


Each of these factors influences the growth rate of plants and hence the uptake of nitrogen.

Timing – when should it be put on prior to cutting silage / hay?

Fertiliser applications to increase yield need to be applied at least 4 weeks prior to cutting silage/ hay. Ideally after the paddock has been grazed, fertiliser is applied and then the paddock is shut up for hay/silage. It is essential this fertiliser application is timed with a rainfall event; 10 mm of rain is normally sufficient. Fertiliser timing for hay paddocks is  generally around the same time, although the shut up period will be greater than 4 weeks. If postponed too long the likelihood of sufficient rain is reduced.

What blend should I use?

If you have done autumn P & K topdressing or soil test results show adequate nutrient levels, Pasture Booster (24-4-13-5) may be sufficient. If nutrient levels are less than satisfactory or autumn topdressing was not done, a blend higher in P & K such as Pasture Promoter (16-8-13-7) may be required. If nutrient levels are high, the use of urea may be appropriate. If paddocks treated with nitrogen or a nitrogen blend are grazed prior to cutting silage or hay the yield will be significantly reduced. Do not re-admit stock to any areas treated with nitrogen for a minimum of 21 days.

Product Analysis Rate (kg/ha) Comment


16-8-13-7 200 – 300 Sources of N to boost production P, K & S to maintain soil nutrient levels.
Pasture Booster 24-4-13-5 150 – 200 Source of N, P & K to boost pasture or hay where normal Autumn topdressing has already been applied.
Urea 46-0-0-0 80 – 100 Nitrogen only.


Note: These are examples only – consult your local Roberts representative to tailor a fertiliser program to suit your specific needs.



Slug Control in Tasmanian Crops and Pastures

With recent good rainfalls in Tasmania it is imperative to be on the lookout for slugs on emerging crops. Slugs are a serious pest on many crops and pastures, as adoption of minimum tillage practices increase on Tasmanian farms.



Less tillage combined with retention of residues (stubbles) enables greater food sources and shelter for these pests. Slugs can kill seeds and eat plant tissue on germinating, often whole seedlings are consumed. Slug damage is often under estimated as they are mostly active at night.



Metarex from Agnova was originally developed for European conditions, and performs long after inferior baits have collapsed. Metarex has a consistent pellet size that flows smoothly and spreads evenly for optimum coverage. The unique formulation is resistant to shattering which means more baits reach the ground when applied by spinner type spreaders. With approximately 60,000 baits per kilogram, Metarex has a consistent size and number of effective bait points per square metre, that provides optimum crop and pasture protection.

Metarex is an all-weather slug and snail bait that provides fast, consistent control, even under wet and difficult conditions in Tasmania. Paddock monitoring early morning or evening is essential for determining the presence of slugs and snails. A wet hessian bag or slug mat placed on newly sown paddocks should be standard agronomic practice.

For more information contact your local Roberts agronomist in Tasmania.


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Success with Growing Forage Brassicas, Tasmania


Success™ with Forage Brassicas starts with Success Neo.

Success Neo Insecticide from Dow AgroSciences provides control of a wide range of caterpillar insects in many crops.  Reliable control of diamondback moth in forage brassicas gives graziers the potential to again consider this high quality, low cost feed as part of their production system.


Agronomist Dan Sutton from Roberts, Smithton, Tasmania agrees:  “They’ll now be able to grow forage brassicas without fear of losses that have plagued intensive farming.  It crosses over dairy, sheep and beef operations.  A lot of the mixed cropping operations will be able to now consider forage brassicas as part of their farming enterprises, with Success NEO delivering outstanding diamondback moth control.  It’s very effective.”

Forage brassicas can provide quick and abundant feed, with high digestibility, energy, and protein, resulting in excellent livestock weight gains.  Forage brassicas also provide a ‘break’ in the cycle for weeds and disease and can inhibit the growth of disease-producing organisms and reduce the incidence of nematodes.

While producers have long been aware of the benefits of forage brassicas, the major downside has been the risk of large-scale crop damage posed by diamondback moth.  The risk of crop loss is so high in some areas that farmers have turned away from growing forage brassicas and have actively been looking for alternatives. Diamondback moth (DBM) is so prevalent in Australia in spring and summer that it is normal to find larvae (caterpillars) in forage crops such as turnips, rape or Pasja.



Diamondback Moth have become resistant to most of the current chemical options.  Resistance to synthetic pyrethroids and organophosphates is now so widespread as to render these older chemicals ineffective.  Although these chemicals are ineffective on DBM they continue to be used for other pests.  As they are broad spectrum products, they decimate beneficial insect populations, biological control fails and the result is even worse crop damage.

Success Neo Insecticide gives excellent control of DBM, and since it is also selective to the main beneficial insects, it allows them to provide a secondary means of control.  It has a high level of environmental and user safety and defined stockfeed withholding periods make it easy to manage.


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