DairyNZ: 6 key findings about catch crops and fodder beet

The farmers' levy is being used to fund research into the animal health effects of fodder beet.

Over a six-year period, DairyNZ is investing $450,000 of the farmers' levy annually in a research programme called Forages for Reduced Nitrate Leaching (FRNL).

Here, we highlight some key discoveries made about catch crops and fodder beet.
In Canterbury, FRNL has been investigating the potential yield and reduced risk of nitrate leaching from using oats as a catch-crop after winter-grazed kale.

We found catch crops can:

* Reduce soil mineral nitrogen and nitrate (N) leaching by about 30 per cent
* Increase dry matter (DM) yield on the same land by 6-12t DM/ha annually, depending on the season and sowing date
* Cut the cost of growing DM by 3c/kg DM.

That's good news but, before sowing a catch crop, farmers should consider whether their farm has reliable summer rain or irrigation for establishment of the next main crop. You should also think about whether it's possible to get heavy machinery on your paddocks in July or August, or at the latest before mid-September.

Testing quality

In Lincoln, FRNL has been looking for differences in the yield and nutritional value of fodder beet sown from early September to early December, and harvested in June and September.

We found DM yield and nutritional quality of fodder beet was the same in June and September, meaning there was no yield or quality lost by harvesting later. Crops sown early had higher DM yield because they had more time to grow.

Health effects

The effects of fodder beet diets (low in N) on urinary N excretion and cow performance have been evaluated in late lactation and during the non-lactating period.

The results show that, when managed properly, fodder beet can lower animals' N intakes and urinary N excretion without negatively affecting their health and productivity.

Here are some key findings from the research:

* A diet of 40 per cent fodder beet with autumn saved pasture almost halves the urinary N concentration in a lactating cow.
* Feeding 40 per cent or less of DM intake as fodder beet to cows in mid to late-lactation reduces their risk of acidosis.
* Feeding 70 per cent or less of DM intake as fodder beet to non-lactating cows reduces the risk of not meeting their nutritional requirements.¦

For more information on these results, go to dairynz.co.nz/frnl

- Inside Dairy