Minimising risk of nitrate poisoning
Coming into autumn, maize and summer crops have been harvested/ grazed and farmers are planting their next crop or establishing new permanent pasture.
One of the impacts of this damage is reduced pasture production. Our data is showing a lot less pasture silage being made, simply because there has been little or no surplus generated. Even the pasture silage yields off winter grazing blocks are down, as these were also pugged.
On top of this, due to the wet spring many farmers have struggled to plant their turnip or chicory crops on which they have traditionally relied to get through summer.
What does this all mean in practical terms? Simply this: there will be less feed available this summer to fill feed gaps.
Farmers in warmer districts know that securing their summer or autumn feed supply is of utmost importance. With all contract maize silage already committed for 2018, you won’t be able to rely on buying in maize silage as and when needed. Therefore the planning needs to be done now if/when summer dry turns to drought.
The good news is that there are crops farmers can still successfully plant as we move into summer to fill any feed deficit. Two highly successful summer feeds include green-feed maize and a forage sorghum x sudan grass crop. These crops are also excellent options if you know you don’t have enough grass silage, or you have struggled to establish brassica, chicory or fodder beet crops.
Both maize and sorghum are relatively drought tolerant and they love heat, meaning they are ideal for planting in summer. They will establish well in early summer as long as they are planted into moisture. Both have an extensive rooting system, meaning they can use any water they get very efficiently. In fact, maize water use efficiency is three times that of pasture. It will continue to accumulate yield long after shallow rooted species have stopped growing.
Greenfeed maize
While maize is traditionally fed as silage, the beauty of a greenfeed crop is its flexibility. If you don’t need the feed prior to silage harvest time it can be ensiled.
Greenfeed maize is reasonable quality (10.3-10.8 MJME/kgDM), with higher energy levels being achieved as the grain content increases. Greenfeed maize typically has slightly higher (9-10%) protein levels than maize silage.
Crops can be break-fed or chopped using a maize harvester or a flail-type mower. Feeding behind an electric wire reduces crop wastage from trampling.
There is just one caution: take care when green-feeding crops have high amounts of grain present, as excessive grain intake can lead to acidosis (grain overload).
Forage Sorghum-Sudan grass
Another option for summer feed is a forage sorghum x sudan grass hybrid such as Pioneer brand Bettagraze. These have been around for a long time and have been used extensively by a dedicated group of farmers in northern New Zealand.
These hybrids are excellent options for summer feed in warmer districts, producing good yields of moderate quality feed in a relatively short timeframe, even under dry growing conditions.
Because they grow rapidly, crops can be grazed or harvested in as little as 35-45 days after planting for first grazing, with further grazing able to be achieved at regular intervals.
Key benefits of forage sorghums include a larger seed that can be planted into the soil moisture zone, rapid early growth and quick recovery after grazing, delayed flowering for easier management and high sugar content, fine stems and a high leaf-to-stem ratio for excellent palatability and good feed value.
Like maize these plants are pretty versatile. They can be grazed, but if the feed is not required it can be harvested as silage or hay and stored for feeding later when there is a genuine feed deficit.
As is the situation with all rapidly growing summer plants, they can have issues with high nitrate levels, which need to be managed.
This is done by first testing to see if they are high and if they are then give animals their feed after a feed of grass so they’re not being fed on an empty stomach. If you can, the other option is to wait until the nitrate levels have fallen to a safer level.
If you need to know more about either of these options get in touch with your local merchant or go online to pioneer.co.nz
• Ian Williams is a Pioneer forage specialist. Contact him at This email address is being protected from spambots. You need JavaScript enabled to view it..
