Replacing Fertiliser Nitrogen without Pain.

Replacing Fertiliser Nitrogen Without Pain

Peter Burton
20th July 2009


On an increasing number of farms during the last six seasons fertiliser nitrogen has been reduced or completely removed without any loss in pasture production and with an impressive range of benefits.

Nitrogen is an essential element for plant growth and when any growing system has become dependent on regular applications of fertiliser nitrogen, the rapid removal of part or all will result in less growth.

Replacing fertiliser nitrogen with a CalciZest and DoloZest based nutrient programme replaces fertiliser nitrogen with nitrogen provided via natural systems with no loss in total pasture production.

Monitoring of properties over the last six years has shown that not only can a DoloZest/CalciZest based soil fertility programme replace costly and potentially damaging fertiliser nitrogen inputs, but these programmes also provide a range of other benefits.

Comparison of growth rates between the ESI monitor property near Edgecumbe and the DaiyNZ property indicates that on the ESI monitor property a higher percentage of the total pasture grown throughout the year was grown over the months from October to June.

These are the months of greatest milk production and the most profitable production is from high quality, easily digestible, high clover content pasture.

The following table is a direct comparison of the percentage of clover in the sward of 6 properties using CalciZest/DoloZest based programmes compared to 6 conventionally based programmes.


                                                                Clover % in pasture

                              properties (6) with DoloZest            properties (6) without DoloZest
                                         & CalciZest                                         & CalciZest

September                               20%                                                   11%

October                                    24%                                                   12%

November                                31%                                                    12%

December                                35%                                                    18%



Neither clover flea nor weevil has a significant impact on the clover grown on the calcium and magnesium rich based programmes. Predators and pests only attack systems where plants are already weakened.

It has long been known that the use of fertiliser nitrogen in grass/clover based systems reduces the number of clover plants per hectare and the quantity of nitrogen fixed by clover.

Clover nodulation, the process by which clover fixes nitrogen, is also reduced and clover plants tend to use nitrogen rather than fix it when regularly supplied with nitrogen. Work at No 2 Dairy also showed that nitrate leaching increased, as did ammonia loss to the air.

The use of CalciZest this spring at a rate of 400kg – 500kg/ha will provide more total pasture with higher clover content ensuring increased total animal production, more nitrogen fixed naturally and less leaching.

CalciZest can be applied to all areas used by lactating animals. Areas grazed by stock prior to calving/lambing, where magnesium is required, will benefit from an initial application of DoloZest.