Risk Free Fertiliser N Alternative.

Risk Free Fertiliser N Alternative

Peter Burton
21st February 2010

With the almost inevitable increase in the price of conventional fertilisers, many long-term pastoral farmers and horticulturists are attempting to evaluate the claims of companies offering more eco-friendly, sustainable, and cost-effective products.

There is likely to be an element of truth in the claims made by all sellers of ‘fertiliser’, however as there is no single product that meets all nutrient requirements there are two questions that can be asked.

How does this product fit into a sound nutrient programme, and where is the long-term work to support the claims?

Trial work comes in many guises, there is a great deal of soundly based research work undertaken throughout New Zealand by various groups. For farmers and growers the most important aspect is the result from use in practical farming situations.

Many farmers perceive a substantial risk when considering any change from a conventional fertiliser nitrogen driven, water soluble nutrient based fertiliser programme. This need not be the case.

With plenty of evidence that driving any long term growing situation, particularly a pastoral one, with fertiliser nitrogen is simply not sustainable, the risk comes from continued dependence on it to sustain production.

The greatest response to fertiliser nitrogen nearly always comes from the first application. From then on, if used frequently, responses steadily decline along with increasing animal health issues, greater need for weed and pest control, and more frequent renewal of pasture.

As soils become increasingly degraded both moisture and nutrient holding capacity declines. Could this be the reason for the perception that seasonal changes are becoming more rapid and extreme?

Pasture dry matter production measures from properties using biologically fixed nitrogen rather than fertiliser nitrogen indicate that total growth is at least as high as conventional properties, and that growth is more evenly spread throughout the major growing season.

Winter and early spring growth, when soil temps are less than 10°C, is slower on the biological properties but compensated at least in part and possibly fully by the higher energy levels of the pasture grown. Should March and early April pasture production be less than budgeted for, small quantities of fertiliser nitrogen may be introduced to increase the growth of grasses prior to winter.

The condition score and liveweight of milking cows on the monitored properties are excellent, with all but a few animals needing to increase weight and condition score prior to calving. Known MT rates are variable, information at this time suggests a maximum of 7.5%.

Reducing dependence and eventual removal of all fertiliser nitrogen can be achieved by ensuring that the energy removed is replaced by that supplied from natural and sustainable sources.