Correct soil, reap profits

If you correct pasture deficiencies, you're well on the way to better profits


On Farm
A 30-year-old fertiliser trial between Coonabarabran and Binnaway (central west NSW) showing the benefit and build-up of soil fertility.

A 30-year-old fertiliser trial between Coonabarabran and Binnaway (central west NSW) showing the benefit and build-up of soil fertility.

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Profits are always better if soil deficiencies are corrected.

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AS FOR cropping, pasture production will be sub optimal if soil deficiencies are not corrected. Feed quality will also be sub optimal and animal performance well below what it could be. Profits are generally far better, despite added costs, if pasture soil deficiencies are addressed.

In our own example, from land purchased almost a decade ago for around $1600 a hectare, in the past few years we have achieved gross margin returns (gross income minus variable costs) of $300-$350/ha (2018/19 may be less because of drought). The relatively cheaper land value is because it is to a large degree lighter soil with low natural fertility.

Greater gross margins/ha I am sure could be made than we currently are if we ran a more sophisticated business with greater use of fodder conservation, mini feed lots and different enterprise choice. For operation simplicity we run a trading enterprise buying steers around 250kg and selling within the year at about 500-600kg/beast.

Without fertiliser, which costs us around $50/ha applied to tropical grass and native grass-based pasture (that includes winter legumes), I reckon we would be lucky to make $100/ha gross margin. Fattening businesses only work with ample quality feed.

Many other aspects need to be part of the pasture management including species choice, sound establishment and sound grazing management. But without correcting soil deficiencies all other aspects would be for next to nothing.

In many (most) districts like ours good quality as well as so-called poor-quality soil are deficient in sulphur. Lighter and medium textured soils are generally also almost universally deficient in phosphorus before upgrading. Some basalt derived soils are quite high in natural phosphorus, unless mined by long cropping with no phosphorus replacement, but low in sulphur.

All the bad things some people tell you about conventional fertilisers such as superphosphate (generally by those marketing so called alternate products with various claims such as enhancing biological activity) generally have little science behind their criticism.

The fact is that if a deficiency exists, it needs to be corrected with a product that has that element in an available form. Not doing that locks one into poor pastures and poor profitability forever. There are no magic bullets.

That doesn’t mean you can’t be organic or use appropriate alternative products, although often they may be more expensive to correct a given deficiency. For example, mined gypsum (pure gypsum 18.5 per cent sulphate sulphur), provided fine and pure enough, can be a good source to correct sulphur deficiency.

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Various animal manure products, when applied at high enough rates can correct deficiencies like sulphur phosphorus and nitrogen. Animal manure products can be quite variable in chemical composition and for elements like phosphorus around half of it can be in a low availability form.

Restrictions can apply to suitability of manure-based products for organic approval. Some waste products composted (for example vegetation) can also supply useful amounts of nutrients but again levels are variable.

There is plenty of evidence that fertilisers such as single super can help build soil organic matter and soil quality aspects such as increased biological activity.

There is also good evidence that soil levels of elements such as phosphorus and sulphur can build-up after repeated superphosphate applications. In our own property’s case this has occurred and less frequent application is now feasible. There is no truth in that conventional fertilisers makes plants “lazy” and therefore you need to apply it every year.  Soil testing is a good guide to fertiliser type rate and frequency needs.

Next week. Tough early sown winter crops.

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