Successful Forest Farming

Nutrition is the key

By Matthew Kilby and Graeme Sait

The financial appeal of growing hardwoods in a ‘fast-food’ world where cash-flow is king has been limited, to say the least.

Pine and paulownias have dominated the timber growing arena, as softwood profits can be enjoyed by the current generation rather than the next. However, recent research suggests that the half-century crop cycle often associated with cabinet hardwoods can be dramatically reduced. Hardwoods can be harvested within twelve to fifteen years if provided with the right conditions. These ‘conditions’ include a synergy of: species mix, planting density, soil structure, seedling preparation, grass and weed control, pruning techniques and pest and disease management.

The first two years governs the length of the crop cycle. A poor start ensures at least forty years until maturity, but a kick-start in the first 24 months has reduced maturity time by up to 60%! In this context, farming cabinet timber becomes a highly attractive financial proposition.

Research has highlighted the importance of the above criteria for rapid maturity, but there is one critical link that has been largely ignored; new plantings usually involve ex-pasture country and cattle growers are notorious for their soil-nutrition neglect. Usually they choose to supplement nutrition in the animal rather than correcting problems in the soil. These soils should always be tested and nutritionally corrected before planting to ensure that growth during the critical two-year foundation period is maximised. There are four core-components in this maximising process:

  1. mineral balance
  2. microbial balance
  3. sustainable herbiciding
  4. natural growth promotion stimulation

MINERAL BALANCE

Correction of all mineral deficiencies is essential but the first priority is always calcium. Calcium is the king of nutrients. There is no point applying any other nutrients until calcium levels have been optimised for that particular soil type. Calcium is the trucker of all minerals. Mineral uptake and associated growth and timber quality will always be limited in the absence of sufficient calcium. The right amount of calcium to apply in any given soil type is best determined by a good consultant who understands basic soil-balancing principles. Soil Testing is a analysis service that can also help growers understand soil nutrition, nutrient requirements and the ratios involved in achieving soil balance. There are some important ratios involved in building a productive soil. The calcium/magnesium ratio, for example, is the single most important ratio in this soil-balancing process. When this ratio is correct, there will be a breathing, open, well-drained soil, nutrient uptake will be optimised and beneficial soil-life will enjoy ideal living conditions.

Phosphate is the second most important consideration when seeking mineral balance. This element is critical for photosynthesis. Photosynthesis produces the carbohydrate energy for plant growth and associated root development. Phosphate is also critical for the micro-organisms, which are the prime-movers in successful timber farming. Free-living, nitrogen-fixing bacteria like Azotobacter, for example cannot operate efficiently without adequate phosphate. Timber plantations need to have this natural nitrogen system performing efficiently, as the application of excessive synthetic nitrogen has proven detrimental for timber quality.

All of the trace elements should be boosted to minimum acceptable levels. Zinc and boron are particularly important. Zinc is needed to produce the growth promotants, which determines leaf size. A small leaf produces stunted growth, as the smaller the leaf, the lower the available ‘solar panel’ area available for converting the sun’s energy to plant growth energy.

Boron is a highly leachable element which is often neglected in long-term crops. It is not unusual to see a mere teaspoon of boron double the yearly growth of a tree that is boron- deficient.

MICROBIAL BALANCE

Leading US microbiologist, Professor Elaine Ingham, has demonstrated that some crops prefer a bacterial dominated soil, while some others will only flourish in a fungal dominated soil. Timber crops need a fungal dominated soil – kick up some leaf litter the next time you visit a rain forest and witness the visible fungal activity. The ex-pasture soils often chosen for timber farming are always bacterial dominated, and this immediately becomes a limiting factoring in the rapid establishment of the tree crop. It has been assumed that the herbiciding of the grass cover reduces competition for moisture and nutrients while also reducing the growth loss associated with the toxic emissions of some grass species in their battle for supremacy. While these assumptions are essentially correct, the major gain from completely removing the grass from the picture actually relates to this fungi/bacteria balance. When the grass is gone, the fungal dominance can development without hindrance and this offers a huge ‘kick-start’ potential. This fungal dominance can be further enhanced by the application of fungal dominated compost and/or mulch i.e. add forest litter to traditional compost to ensure the proliferation of fungi. Liquid seaweed is another productive fertiliser that promotes fungal growth. While fish fertilisers promote bacterial growth, liquid kelp is also ideal for this purpose.

SUSTAINABLE HERBICIDING

The use of herbicide to remove pasture competition is a dual-edged sword. While the practice successfully nullifies the competition, it can also seriously disrupt beneficial soil-life. Herbicides kill algae – single-celled plants which are an essential food source for both bacteria and fungi. Algae live near the surface to access sunlight, and like all plants they produce sugar from photosynthesis. These carbohydrates are the energy source for the beneficial microbes. All herbicides destroy algae, as a single-celled plant has absolutely no resistance to herbicides. When algae are removed from the food chain, there is a corresponding drop in the numbers of fungi and bacteria, which derive part of their energy from this plant.

So we have a dilemma – on one hand we have a practice that builds the likelihood of desirable fungal proliferation, but at the same time the herbicide is reducing the overall numbers of fungi in the soil. There is a solution here, and it involves the use of a liquid called fulvic acid in conjunction with every application of herbicide. Fulvic acid is a remarkable material. Fulvic acid increases the sustainability of herbicides: Professor Elaine Ingham reports that the herbicide residues can remain in a soil for six to eight months during which time they can continue to compromise soil-life. If your child ingests poison and is rushed to Outpatients for treatment, the first step will be the administration of activated charcoal. The charcoal absorbs the toxins to reduce further cellular damage. Similarly, fulvic acid can be used to absorb herbicide residues and remove them from the system. This removal process features a two-way action. Fulvic acid has a Cation Exchange Capacity (CEC) of 1400. Most soils have a CEC ranging from 5 to 25. Fulvic acid, with this phenomenal absorbency, can suck up toxic residues to isolate their damage potential. Fulvic acid is also a powerful microbial stimulant. Microbes are drawn to the fulvic molecules like bees to a honeypot. Many herbicides are actually biodegradable, and this influx of microbe activity can break down and remove the toxins confined within the fulvic storehouse. The second fulvic feature which facilitates detoxification relates to the size of the fulvic molecule. This molecule is so tiny that it can be easily leached from the soil, often taking undesirable residues along for the ride.

The key to herbicide sustainability is as follows:

Always include equal amounts of fulvic acid with your herbicide.

If, for example, you normally use 1.5 litres of Glyphosate per hectare, add an equal amount of fulvic acid, i.e. 1 litre of Glyphosate with 1 litre of fulvic acid per hectare.

We have a product called Herbi-Safe which contains fulvic acid but other ingredients to help with sustainable herbiciding. To read more about it click here.

GROWTH PROMOTANT STIMULATION

When mineral and microbial balance have been achieved, then there is considerable potential to boost this vigour of young trees, using foliar fertilisers containing natural promotants. Tree-Tonic contains multiple growth promotants.

If the two-year challenge is met successfully, then we should have full canopy cover by 24 months. The trees should be strong and disease resistant, reflecting the benefits of this two-year nurturing period, but most importantly, the groundwork has been done to ensure a dramatic reduction in maturity time.

From “QLD FOREST FARMER’S ASSOCIATION NEWS” Volume 2 Issue 11