Tuesday, 3 December 2013
Day 8 - Time for a Tour of the District
Our host Alec Wright; Nuffield Scholar, in Methven graciously showed us around the district this morning visiting his sons farm first thing to drop off some lunch made by Jean, Alec's wife. We looked at the silage operation before moving up to some higher and stony ground to look at some direct drilled grass reseed. This field was coming up beautifully due to the reduced disturbance retaining moisture win the soil. There is no luxury of irrigation this far up the slopes on Mt Hutt. The swedes were also direct drilled into grass stubble that had been sprayed off and were emerging well on the whole although as temperatures reached 29 degrees today and with a stiff breeze soil moisture was paramount. This would also go for wheat production. A single cultivation will reduce the soils water holding capacity by 25mm, which could be important later on in the season.
If cultivated and a North Westerly gale blows, the wind is funnelled down through the mountains and the soil will be eroded by the wind, leaving the field and being caught up by the nearest obstacle, in this case a small hedge. The depth of this top soil was 2 ' deep and seeing this brought back thoughts of the great dust storms of the 1930's and my time in Oklahoma.
The wind can also do some serious damage to the infrastructure of the farms when really unleashed. Earlier this year about 800 irrigators were blown over during winds that reached 200Km/hr in places. This is putting huge pressure on the mechanics required to repair all this damage but without water there are no crops or grass. Production in some areas has fallen away simply because there is no water to keep the crops alive.
We drove passed one terrific looking crop of wheat being irrigated. The plant population was thinner than our UK target but the plants had tillered out very well. The stems and upper leaves were clean of disease and the potential of thigh yield was definitely present. I think this picture sums up the advantage that New Zealand has over the UK when it comes to wheat production. It seems that an abundance of water, (for the time being), and lots of sunshine are the key ingredients to very high yields. But the plants need to be fed correctly and the soil has to have the correct structure to support root development that will enable faster, less restricted uptake of nutrients.
This is where crops like this fodder radish can help in restructuring the soil. The tap root, along with the other 30/m2, are all pushing down through the soil profile, finding a way through any compacted layers in search of water and nutrients. The field had a good population of plants all creating drainage for water infiltration, for when it does rain, and removing any compaction layers. The obvious next step would be to direct drill the next crop to reduce the erosion risk; as evident above, reduce cost of establishment and increase the amount of water available to the following crop. By not tilling; the soil will increase it's organic matter content allowing further increases in the water holding capacity. Seems to me like a good way to progress?