Conundrum for some

Conundrum for some

A recent newspaper article stated “New measurements by Landcare Research show that some soils have lost up to 21 tonnes of carbon/ha, and up to 1.8t of nitrogen.”

The same article also contained the following paragraph, “Roger Parfitt, Landcare Research, says scientists are astounded at the size of the losses in carbon and nitrogen when they sampled the old Soil Bureau sites in 2002 to 2004, but don’t know whether it happened in the last 10 to 20 years or whether it’s a continuing change.”

These figures come as no surprise to many of us working closely with farmers, soil, and stock, particularly those with the perspective of more years experience than we might care to count.

Pasture production in general based on any sound measure that might be applied is declining and has been doing so at least since the early 1980’s.  We have stated this before and the only counter offered has been increased per hectare milk solid production from dairy farms.

What is critical to this argument is the quantity of pasture actually grown.

Carbon in the soil largely provides the potential for pasture or crop production.  Increase carbon content and productive potential increases.

Why then the loss of carbon?  Since the early 1980’s there has been a steady increase in nitrogen fertiliser usage. 

Further research will show that those areas where nitrogen has been applied most heavily will have had the greatest loss of soil carbon, which is why some hill country sites are gaining carbon.  Those sites will have had little or no fertiliser nitrogen applied.

Nitrogen fertiliser alone is unlikely however to account for all the losses that have occurred.  More animals per hectare create more downward pressure on the soil and in wet conditions pugging becomes unavoidable.

Potassium chloride, the most commonly used potassium fertiliser can have a significant negative effect on pasture growth. 

The mix of high stocking rates, heavy use of nitrogen fertiliser, and fertiliser inputs containing particularly muriate of potash, as practised by many farmers will continue to reduce soil carbon levels and potential pasture production.

There are solutions.  The soil improvers CalciZest and DoloZest, manufactured and sold by Eco-Logic Soil Improvement Ltd, when incorporated into fertiliser programmes that provide the necessary inputs of both major and minor elements have the ability to increase carbon sequestration.

DoloZest when applied in autumn will improve physical soil structures over winter.  Increased soil oxygen levels promotes  beneficial soil biology which in turn increases pasture production capacity.

Increased soil biology also increases nutrient availability reducing the need for high levels of nitrogen fertiliser.

Eco-Logic works with farmers where nitrogen fertiliser has been largely removed and total pasture and farm production continues to steadily increase.

For advice on product application rates for your property and information on how we can improve the productivity of your farm phone 0800 843 809.

Read the next article - Providing for Stock in Winter