So that’s a full month of travelling for Nuffield, only a few more left.I’ve stayed for a couple of nights with a Nuffield Scholar from 1976, Jim Halford. He might be known to some people because he invented the Conserva Pak drill, the design of which was sold to John Deere in 2007. Jim is a no-till (or zero-till as he calls it) pioneer, and now everyone in the area is using the technique he developed.
I would not say that it is minimum disturbance no-till, as the drill is made up of two tines, the first of which places fertiliser, and the second one seed. The first tine is set a bit deeper, and serves to cultivate a strip for the seed to go into, and the packing wheel means that it leaves very distinct ridges. This is seen as a benefit as the seedlings are protected from wind until they grow bigger and poke out the top. Jim had tried disc drills to begin with, but found they did not work on his soils – hence he developed the Conserva Pak. I wonder if they might work better now the soil is in better condition?
But I didn’t visit to see a drill. I came because Jim has a pretty unique (sorry mum) setup. The main farm has been in no-till for over 30 years, but in 2000 he started renting some land next door. This land had been conventionally farmed, which is to say it was cropped one year and then fallowed the next. During the fallow period it would be cultivated 4-5 times to keep the weeds under control. In 2001 Jim put it into a no-till system, where it has been ever since.
In 2002, in conjunction with the Indian Head Agricultural Research Foundation (IHARF), they put a trial site on the long term no-till land, and a few hundred metres away, another on the new land. The trial has been running ever since, in a spring wheat/canola rotation, which is standard around here. There were a few different treatments on the site, one to do with phosphate placement, and the others with varying rate of N, from 0-120kg/ha.
The first 10 years’ data has been analysed, and the long term no-till site is much, much more productive than the short term. In fact the long term produced an average of C$120 per year extra profit.
As the graph shows, the longer a field was in no-till, the higher yielding it became, for all levels of nitrogen fertilisation. I think it is interesting that the difference is more pronounced at the lower end, and that ties up with the observations that no-till soils have more available nitrate in them. Another nugget was the in these 10 years, 4 had average rainfall, 3 had above average, and 3 below. In the “normal” years the yields were not very far apart, whereas in extremes the long term was significantly better. Again this would be consistent with the theory that increased organic matter helps both drainage and moisture retention.
Now, the short term field was obviously coming out of about the worst type of treatment you could imagine; half the time it had no growing plants and constant soil disturbance. However, the difference in productivity between these two sites seems so massive to me that it makes me question whether there isn’t another factor at play. The two sites are not immediately adjacent, but the soils were tested and found to be effectively identical – although micro nutrients were not looked at. When I visited the Rogers Memorial Farm in Nebraska, and looked at the data from 34 years of tillage trials, there was nowhere near this level of difference between even full tillage (ploughing) and the no-till, even though less disturbance did consistently come out ahead. That is not to say that the results here are not correct, but I am not going to get excited and think that 20-30% yield increases are possible on our land just from adopting no-till. Which is a shame.
IHARF publish a booklet each year that outlines all the trials they have published results from, and it is an interesting read. Most of it is not relevant outside their local area, but a couple caught my eye. One was that they found a significant yield increase from inoculating peas with rhizobium bacteria at drilling time. I think some trials have been done in the UK on this, without such exciting results; I wonder what the difference is?
The second thing was a trial looking at seeding rate for canola in relation to row widths. We have some rapeseed this year planted in 50cm rows, as opposed to our normal 12.5cm. Both of these were drilled at the same seed rate, but we have been saying all year that maybe the wider rows should have had a lower rate, so that individual plants had more room. According to the IHARF results, this is not the case. It may be possible to reduce the rate slightly, but in general the same should be used regardless of row width. A good example of the quote I put in Day 29’s blog:
“If common sense always worked we wouldn’t need science”