Pasture Growth Data

Click here to view the historical average pasture growth data statistics for New Zealand dairy farms.

Important Notes

All pasture growth rate data must be treated with caution due to the large number of factors that influence the information. E.g. nitrogen fertiliser use, soil fertility, method of measurement, climate, pasture species, irrigation, etc

The data presented here is based on averages from several years for specific sites. Some sites include nitrogen fertiliser boosted growth rates, indicated in the notes column. The years that data represents, the method of assessment and the source of the data are also shown.

Methods

Whole Farm

This method involves calculating growth rates based on changes in pasture cover of ungrazed paddocks. Pasture cover is assessed by rising plate meter (RPM), probe, or by eye. The total grown is usually less than that estimated by the cage method. This shows the effect of management on pasture growth.

Cage

Two cages are positioned in several paddocks typical of the farm. Pasture cover at the start of a period (usually a month) within each cage is assessed by rising plate meter, probe, or cuts. Measurements are made again on a grazed area onto which the cage is rolled. Growth rates are calculated by the "difference" method and equations to convert RPM reading to pasture cover. These equations are usually the ones found on the Dexcel website, but can vary with location.
Annual pasture grown, as estimated by use of cages, is usually higher than that estimated by the whole farm method. Piggot (1997) found that annual pasture grown was 30% higher than that estimated by the whole farm method. The relative differences were greatest in September and from January to May. The role of pasture management was illustrated by the observation that some farms were capable of producing whole farm annual pasture yields within 10% of the cage estimate for annual pasture yield.

For more information, please refer to Pasture production of northern dairy farms. G.J. Piggot, 1997. Proceedings of the New Zealand Grassland Association 59: 103-106.