Guano – a tale of two birds

Kismet’s agronomist, Robert Drewitt discusses the important role guano has played in modern agriculture
North East & Goulburn-Murray Farmer
MADURA MINING: John Jashar, owner and director of Kismet International, inspects the huge reserves of guano, that will be mined to create Madura Guano Gold.

IT was the best of times.

It was the worst of times.

This might have been the thoughts of the guano miners shovelling and bagging guano from caves to load into bags to bring back to Europe to fertilise crops.

In 1609, Peruvian guano was first discovered by the western world.

However, the Incas had been using guano for centuries with strict rules around protecting the sea birds that nested on the islands.

The guano trade began in a commercial form by 1840 when the United States started using guano as its main source of fertiliser.

The use of guano created an agricultural boom.

United States president at the time Millard Fillmore said in Congress, “The duty of the government is to employ all means properly in its power to assure guano is imported into this country at a reasonable price.”

In 1856, the US Government passed the Guano Island Act which allowed any unclaimed islands to be annexed.

So began the hunt for guano to feed the world’s crops.

Today, over 150 years after the 1856 proclamation the world still demands guano as a source of nutrition for crops and pasture.

Today, however, the world is a different place and deposits of guano are not as readily available.

Guano has two main types: the fresh guano from bats and birds that contains nitrogen and older guano that has been either coralised, or in the case of inland deposits, formed into sedimentary rock deposits.

The older guanos are high in phosphorus and calcium but contain no nitrogen.

In respect to Australian agriculture the focus is on the older forms that are imported as a source of fertiliser for both the organic and non-organic farming industry.

The current imported guanos fall into two main categories – inland, mainly Chinese guano, and coastal or sea bird guano, from South East Asia.

Where your Madura Guano Gold® comes from is very important from an agronomy viewpoint as it determines both how available the phosphorus in the product is and if the product contains beneficial silica at significant levels.

This article is the first of 12 in a series that will give the reader a good understanding of the difference between guanos available on the markets, the real effective cost of the product, plus when you need to use guano.

We will also look into phosphorus tie-ups, the Phosphorus Buffing Index, as well as silica’s role as a beneficial element both in the soil and in the plant.

More farming news and stories can be read in the August, 2019 print edition of North East & Goulburn-Murray Farmer or click here to access digital editions.