A Sharefarmer colleague (Gavin) and I attended very interesting and informative meetings addressed by Basil Doonan. The discussion involved the Alexandria dry land systems, pastures and other management aspects in general.
Basil’s comments are based mainly on his experience consulting in Tasmania as well as Australia. His comments supported by research done in Tasmania
Nitrogen should always be regarded as a supplement, this meaning that N should only be applied when grass requires stimulation to grow. This being based on feed demand.
Rule of thumb that an average of 1kg N applied per day of rotation. I.e. in a 25 day rotation you require 25 units of N. Again always bearing in mind your feed demand.
On a kikuyu based system one can apply double the N every second grazing.
One should avoid applying N when your grass is in dormancy. Dormancy meaning that grass is not growing due to lack of moisture. N should only be applied when there is adequate moisture in the soil. This is somewhat different to what we do on dry land farms by applying N in anticipation of rain. Basil maintains that your efficiency of N applied during dormancy can be reduced by as much as 50%. We have to rethink our future applications and rather than anticipating rain we will have a better response to only apply after rains of at least 20mm to ensure the grass will grow and have the ability to utilize the N.
As far as quantities of N, Basil believes if required one can apply as much as 120N in any one application. Basil encouraged us to pull N levels past break even point and ensure we do not under apply nitrogen. This will apply mainly to our dry land hay pastures like Rhodes grass. This will be applied strategically once there is adequate moisture in the soil ensuring that the growing time is maximized. Again this application being based on your requirement for hay and the quality thereof. N application assuming that P and K in order.
Moisture levels should be measured at 30cm as this is where the majority of roots are. According to Basil these moisture levels should be at a minimum of 35kpa/2 Bar (as per tensiometers) at 30cm, below that dormancy kicks in.
Basil believes that monitoring moisture levels on dry land farms is as important as irrigation.
Basil is adamant that the right amount of N applied has no negative effect on soil biology. In fact he believes N has a positive effect.
An interesting comment regarding litter and compost Basil believes if your organics exceed 3% then using chemical fertilizers are a more economic option than litter and compost. Again his view being that chemical fertilizers do not negatively affect soil biology. This is a debatable comment and certainly created interesting discussion.
Gibberelic acid is a very good product that is very effective if used correctly. Soil temperatures should be below 5 degree C to justify the cost. If soil exceeds that then N is more effective. When applying Gibb acid one should chase it on with N as well.
On stocking rate,
Basil believes he has seen a lot of serious over stocking in SA. He maintained that your stock rate should be based on 4 tons DM per cow (450 kg). An interesting rule of thumb to calculate a farms stocking rate.
In summary as Basil always says there is no silver bullet to answer all questions. It remains in the hands of each manager to make the right decision at the right time. The decision must always be based on a balance between economics and feed demand. Nitrogen remains your cheapest form of roughage (in growing grass) but it has to be applied in conditions conducive to growing grass. If not able to grow grass then concentrates and/or roughage will be more economical.
Always remember that N is a supplement as is your concentrates and fodder bank. Do the numbers and always ensure that you use the most cost effective option.
Some comment on cows,
There are critical times in a cow’s lactation where BCS is important to get her to dry off in the correct condition. It is more cost effective and healthier for the cow to catch up body condition towards the end of the lactation. A decision needs to be made at the correct time towards the end of the lactation whether to increase feed to correct body condition. Our individual feeding system will accommodate this.
Try to put colostrums cows on pasture and not in a colostrum cow camp with roughage.
Grazing pastures over the S curve creates shading and wastage and does not optimise the vegetative growing stage. Light must get to the tiller base.
Get Capital and Maintenance fertilizer. Capital fert is P,K and S. We need to nutrimanage our soils to keep them in optimum state of production and “look and see” what is happening.
Quality, Quantity and Survival are the 3 principles of pasture management. Our daily decisions must be based on this.
We asked Basil about a possible other species above what we are currently planting. Only other species to suit acid and water logged soils is what he calls Lodus. I searched this and got Lotus which is the Birdsfoot Trefoil that we know. It is a non bloating legume adapted to poorly drained soils but only needs 600mm rainfall and is cold and frost tolerant. Possibly something to try in some areas.
Nothing new, we’ve heard it all before but nothing like a good old reminder.
Written by: Edgar Brotherton