It’s not run-off into waterways from pastoral land that’s the greatest concern it’s what’s coming out the bottom into aquifers that’s the major contaminator and the quickest and most effective way to stop that is to cease tipping it in the top.
Nitrogen constitutes 78% of the air that we breathe, the top 20cm of pastoral soil holds 5,000 – 15,000kgN/ha. There’s no shortage of the stuff, it just has to be used more efficiently.
And the claim that farmers will produce significantly less and have the value of their land decimated if they are no longer permitted to use nitrogen fertiliser is an argument increasingly difficult to sustain.
The motivation of farmers applying little or no fertiliser nitrogen is to preserve the value of their land by being able to continue producing without environmental damage, and their position is the one that will ultimately prevail.
Any enterprise that destroys the base from which its wealth is generated is simply not profitable, and long-term intensive pastoral farming driven by regular nitrogen applications is just that.
Central government, local and district councils will regulate in favour of the environment regardless of outrage from the farming community. Political power is with those in urban areas and the income generated from pastoral farming can be replaced, potentially leaving farmers with very expensive real estate and limited means of generating an income.
But there is a solution that with a little further development may satisfy all. Ten years of measures from properties applying DoloZest (containing Golden Bay Dolomite) based total nutrient programmes show they grow more total pasture than properties where conventional nitrogen driven programmes are in place.
Production is higher, both total and per hectare, and costs are lower. These farms are equally dependent on the availability of nitrogen for their growth; they are simply making more efficient use of the abundance of it in the air and soil.
Pasture production, based on cage cuts, for the Berryman property, an intensive dairy operation at Otakiri near Edgecumbe in the Bay of Plenty grew 21,635kg DM/ha for the twelve months to the 30th April, an average of 59.9kgDM/ha per day.
10.8kgN/ha has been applied in a total nutrient mix this autumn, to help stimulate grass growth with the arrival of cooler conditions. 19kgN/ha was applied to 60% of the farm in late winter giving an average per hectare input for the season of 22.7kgN/ha.
Although the pasture production figures are yet to be put into the Overseer model previous independent analyses shows the cage figures to be conservative.
Approximately one third of the projected 1,550kg/ha of milk solids this season is from bought in feed leaving milk solid production from pasture in excess of 1,000kg/ha. A record quantity of surplus pasture has been conserved during spring and early summer.
Pastures are dense and even with no obvious fertility patches. Calves are grazed on the property during the growing season and the herd wintered at home.
Pipes measuring Nitrate-N leaching were installed in March 2011 along with the same number of pipes on a neighbouring property using a conventional fertiliser N driven programme. The results to early Feb this year (2014) showed Nitrate-N losses to be around 70% less than those from the neighbouring farm.
Clover is the primary nitrogen fixing agent on the Berryman property with summer pasture a mass of red and white flower. Due to astute grazing management and the increased amount of calcium available for plant uptake clover plants are almost entirely unaffected by flea, weevil or other predators.
With clover containing higher levels of nutrients particularly calcium, the growth rate of young animals is exceptional and the cows comfortably produce more than their liveweight in milksolids each year.