DairyNZ has been working on getting a more accurate measurement for chicory, collecting data over two summers. It reported some early recommendations and findings to the forum.
During the drought some of the only green paddocks on farms were chicory, DairyNZ scientist Jamie Haultain said. This is because ryegrass struggles in these conditions with it shallow root system whereas chicory’s tap root can access soil moisture at a deep level more consistently during dry periods.
Chicory, with its tap root, is able to produce high yields in summer, he said. From October to May you can generally expect about 8-13t of dry matter (DM) per hectare and if the crop goes through to the following May, an 18-month period, you can expect 18-22t of DM per hectare.
“It is a strong feed source for many farmers now but, as there’s no real way for farmers to measure this, DairyNZ has tried to find a way for farmers to walk around their paddocks and estimate it,” he said. Data has been collected on the project over two summers, with the last summer’s results yet to be fully analysed.
Using the rising plate meter, the standard formula for estimating rye grass is 140 times the clicks plus 500. So 20 clicks is 2300kg of DM from ryegrass, Haultain said. But their studies showed with chicory 20 clicks on the plate meter represented only about 1700kg of DM. So if you use the standard equation for chicory you are grossly overestimating what is in the paddock for cows.
So for chicory, farms could use an interim equation of 90 times clicks plus 80, but further analysis was underway. Meanwhile a simpler method is to halve what your standard rising plate meter equation for ryegrass is telling you, Haultain said.
Haultain outlined some of the variables which necessitated further analysis. Chicory plant density was one. In December, with the young plants, there were about 200 plants/m2 , and by early February it was down to 100 plants/m2. It probably averages out at about 150 plants/m2, he said. Plant shape can also cause measurement problems: some grow upright and others flat. Mature crops have stems which can grow very high and they are eaten so they are a feed source. Avoiding measuring them will cause underestimation, however including them could cause a gross overestimation of what is in the paddock.
Haultain said the take home messages were that demand for estimating chicory yield is increasing but the standard rising plate meter equation overestimates chicory.
“However you can use your standard plate meter formula and halve it. That will give you a ball park mark,” he said.
“DairyNZ is developing a new chicory equation however it is only suitable for young crops.
“Look out for the DairyNZ management practice guide for chicory which is coming out later this year.
“It will include a rising plate meter equation.”
