The Future of Soil Fertility

The Future of Soil Fertility

15th June 2011
Peter Burton

One of the great advantages of working with family owned and operated farming enterprises is the historical perspective they are able to provide and of late there has been an increased discussion regarding pasture production now compared to the late 70’s and early 80’s.
 
Those of us that have had the privilege of being involved in pastoral farming for that period of time or longer are aware that although total farm production, particularly milk solid production from dairy farms, has increased significantly since 1980 this does not necessarily reflect a similar increase in pasture production.
 
In the Rotorua/Bay of Plenty region the rule of thumb for most dairy properties in the early 1980s was that they were able to grow enough feed to carry a milking cow to the acre (2.5cows/ha), grow all young stock (25% of milking herd), and provide sufficient supplement in the form of hay and silage to winter at home.
 
This historical perspective is important because it is still the production from grass that provides the profit in pastoral farming.  Supplement brings increased cost and were it possible to make profit from supplement alone we would have seen the development of small acreage dairy properties with the facilities to feed mostly brought in feed.
 
With new banking regulations the cost of debt to farming enterprises, particularly highly indebted ones, is likely to increase.  That extra cost will necessarily need to be met from the profit generated from pasture.
 
We receive enquiry from farmers who have become increasingly aware that their future lies in being able to grow more total pasture and focus their enterprises around efficiently converting it to meat, milk, wool, or whatever else it is they are selling.
 
The way forward is our ability to have soils providing more annual growth and the only way that can be achieved is through systems that ensure that each year more humus is developed on every hectare.  Humus provides the potential for increased growth and is regarded by some as more valuable than gold.
 
The current soil fertility model based on the regular use of water soluble N, P, K, S, has only been embraced for the last 50 years, and the now regular use of nitrogen fertiliser for the last 20 years.  The increased use of these products provided rapid initial growth in pasture production, however, has the recent reduction in pasture performance and persistence been as a result of the overuse? 
 
There is a tendency to abandon practises that are failing and embrace new technology often based on claims that don’t bear close examination.  The results achieved by an increasing number of farmers using conventional fertiliser inputs in conjunction with DoloZest and CalciZest show consistent and steadily increasing production over time.
 
Not only is there steadily increasing pasture production the cost is markedly less than systems using high rates of fertiliser nitrogen.  The cost of the nutrient inputs including cobalt and selenium for the Berryman property near Edgecumbe last season was a little over $500.00+GST per hectare.
 
The cost of nitrogen applied in the form of urea, the cheapest form of nitrogen fertiliser, is currently $1.54 per kg of N. The cost of applying 250kg N/ha is therefore $385.00+GST/ha without the cost of all other essential nutrients.