How to Establish Tropical Pasture

Why you should consider improving pastures

More feed, better quality = more reliable production

In most Northern pasture systems, unimproved or native grasses have a very limited window of feed quality (4-6 weeks) after the start of the wet season. These species quickly loose quality as they turn reproductive and protein, energy and overall digestibility drop quickly, and its unlikely that new growth will occur.

By increasing quality through pasture improvement strategies such as planting improved species extra weight gain, and increasing carrying capacity can be achieved. Improving pastures can give the manager greater flexibility as daily weight gain can be lifted, conception and weaning rates can be improved and feed can go further into the season providing a profitable resilient grazing system.

How do I improve my pastures?

Pasture Renovation

Full pasture renovation and new species establishment is often the most effective way to improve pastures.

• Preparation is key, follow the 7 steps of successful pasture establishment
• Aim to improver smaller paddocks, to improve grazing management and utilisation
• Improve better soil types first
• Select species and varieties that suit your situation - Breeding or Finishing
• Utilise pasture mixes to extend growing seasons and have more feed on offer and maintain quality throughout the season.

Over-sow

Oversowing can be a common practice mainly with Legume species in extensive areas or out of season annual species in higher rainfall environments. When done correctly, oversowing can be a very productive profitable investment, however is often more risky than full pasture establishment. Oversowing of Tropical or Temperate legumes can provide large increases in feed quality (protein and digestability) as well as being a natural source of nitrogen for your pasture systems.

• • Legumes require good grazing management and recovery after grazing. OTHERWISE they will be overgrazed and be lost out of the pasture
• Variety selection is key, choose quick, regenerating legumes so they can compete with established grasses
• Ensure you choose some varieties that are quick to flower, or hard seeded to improve persistence and longevity of legumes in pasture system
  Eg - Tropical Legume Mix- Spellgrazer Desmanthus, Presto Burgandy bean into established tropical grass pasture

Faecal Seeding

Faecal seeding can be a great strategy to introduce legumes into extensive systems. This works extremely well with the use of supplements such as dry licks in northern situations

• Cheap and labour efficient way to get legumes into pasture system
• Manure can be a very favourable seed bed for nutrients, especially important in northern situations with poorer soil types and nutrition
• Can be utilised as a strategy to maintain seed bank levels to ensure legumes persist in the system.

Legumes in Tropical Grazing Systems

Legumes with their high protein content and high level of digestibility are an excellent source of nutrition for stock and maintain quality longer into the season than grasses

• High in Protein
• High in Digestibility
• Ability to fix atmospheric Nitrogen
• Tropical Legumes are Non-Bloating
• Some are hard seeded = improving recovery after dry season and drought
• Increased stocking rates + Weight Gain = Quicker turn off rates
• Aids in stopping pasture rundown
• Not affected by pasture dieback

Legumes provide significant increases of feed quality, especially when grasses have turned reproductive, as well as being a nitrogen source for the pasture.
Legumes can readily supply 16-18kg of Nitrogen/tonne of dry matter produced. This can equate to 150-200 units of N over the season equivalent to 300-400kg of Urea fertiliser.
Including a legume into a grass based pasture therefore reduces the requirement for N Fertilisers, increases forage yield, seasonal growth and quality increasing productivity dramatically.

Legumes are up to 25% more digestible than grasses, for every 1% increase in digestibility there is a 3% increase in animal performance.

Warm & Cool Season Tropical Legumes

Warm Season Tropical Legumes
Legumes that grow over summer such as Desmanthus and Burgundy Bean can provide large improvements of feed quality. In the North, case studies have shown that addition of tropical legumes to grass based pastures can lift carrying capacity and animal performance by 20%.
The increase in feed quality is extremely important later into the season when grasses turn reproductive and lose digestibility improving overall productivity whilst also providing a source of Nitrogen to the pasture

Cool Season Temperate Legumes
The addition of winter growing legumes to tropical grasses can provide large extension to the overall growing season of the pasture. In Sub-Tropical cross over zones addition of these legumes provide high protein, highly digestible feed in Autumn and winter when grasses are lowest in quality (senescing or dormant).
The additional energy and protein from legumes can greatly improve utilisation of the dry feed base, similar to that of a lick supplement.

Legumes are extremely specialised to soil types and climate zones, speak to your local territory manager to find the variety to best suit your individual situation.

Beating Pasture Run Down

Pasture Rundown is a decline in pasture productivity over time. Tropical Grasses are extremely productive at the start and produce large amounts of biomass, this overtime with increased production and turn off can lead to removal of nutrients and tie up of plant available nutrients.

Pasture rundown is caused by declining plant available nutrients, importantly Nitrogen. In rundown pastures nitrogen is still present but it can not be utilised by the grasses until it is mineralised and becomes plant available.
Rundown can result in reduced grass growth by up to 50% and the flow on can see similar losses in carrying capacity and animal performance.
Pasture improvement activities can help tackle run down, adding fertiliser is a simple short term solution. The addition of tropical legumes is a longer term solution to tackling pasture run down, legumes fix atmospheric nitrogen that is plant available to the existing pasture system.

Short term fallows or pasture/crop rotations can also aid in release of tied up Nitrogen Other activities such as cultivation or blade ploughing can increase nitrogen cycling, promoting the release of unavailable N that is tied up, however this does not increase the level of nutrient in overall soil and there is still an overall declining trend of productivity in the pasture.
 

7 Steps to a Successful Pasture

	Planning & Preparation Pasture improvement is a lengthy process, look to have a productive pasture plan. Prepare your paddock early and reduce weed competition before pasture improvement is considered.
	Know Your Soil Conduct a soil test Amend soil nutrition, condition and constraints
	Pasture Selection Choose pasture species by climate/rainfall zone, soil type, frost tolerance Choose correct varieties for your production type
	Timing Favourable climate conditions are desirable in the 3-4 weeks following emergence. Time plantings for soil temperature, rainfall, avoiding frost in late season planting Plant into well prepared ground, with good subsoil moisture
	Sowing Choose the appropriate method of sowing Use the correct rate for your sowing method Ensure good seed soil contact is achieved Monitor planting depth
	Establishment Don’t graze until plant is “anchored” Graze lightly to encourage tillering Spell pasture in late summer to allow seed set
	Maintenance Practice good grazing management principles Strategically fertilise to optimise pasture performance Maintain good legume component

Planting Timing Checklist

Each individual species has different requirements for germination and establishment. But as a rule of thumb, when dealing with tropical pastures you can use the following as some parameters

• In normal tropical planting window for your region
• Soil temperature 16°C and rising, with no cold fronts predicted
• Ambient temperatures of 20°C and nights above 10°C for a period of seven to ten days.
• Rainfall Predicted in the coming weeks.

Planting rate and planting depth are critical. Look to use the correct rate for pasture performance and productivity and ensure planting depth does not exceed 10mm.
Generally, sowing method and sowing timing can have a large bearing on what seed and seeding rate is required to have a successful outcome.
Generally:

• Direct drilling, advised seeding rates from guides
• Broadcasting/ surface application, Significantly higher seeding rates than guides

However it is important to understand how specific conditions around planting may impact the rate or your choice of seed. e.g. planting into heat or dry sowing.

Planting Depth

Tropical pasture species are sensitive to planting depth, seed should be sown less than 10mm deep and ideally pressed in with a press wheel to get good seed to soil contact. As they are small seeded they struggle to emerge from depth, so extreme care should be taken to ensure the desired depth is achieved.
It is critical to monitor throughout the planting process to ensure maximum establishment.