October 3, 2019
Setting-up Heavy Land for Spring Sowing without the Plough
Heavy ground for spring sowing needs to go into the winter both weatherable and weatherproof as well as compaction free and bacterially active, visitors to the start of a state-of-the-art iFarm soil management trial in Lincolnshire were told this autumn. Something that is, all too often, easier said than done.
The Agrii event in conjunction with Roy Ward Farms, put 10 different min-till cultivators working from 1” to 8” through their paces on Glebe Farm’s heaviest clay loam land at Leadenham. Their task was made all the more challenging by noticeable harvest trafficking damage sustained following a summer seeing 130mm of rain in three days on one occasion – not to mention 10mm of rain just ahead of cultivation that left the soil below 20cm on the edge of practical workability.
The 18ha field is to be sown to spring barley with a number of different drills next year at right angles to its wheat stubble cultivation and taken to yield, allowing the farm and trials teams to make the best possible comparisons of the performance of the various equipment combinations.
“Amongst other things, this will allow Andrew Ward to benchmark his long-standing and highly successful Simba Solo cultivator and Freeflow drill system against other establishment regimes,” explained Agrii trials manager, Steve Corbett.
“In particular, to see whether shallower cultivation and less soil movement at drilling could offer significant savings in fuel cost and time while maintaining the high levels of cereal performance and black-grass control which Glebe Farm has achieved in recent years.”
“We haven’t ploughed any ground here since 2002,” Andrew told the 100+ visitors to the event. “And our zero-tolerance policy to grassweeds means we’ve just completed our fifth black-grass free harvest. Winter wheats continue to be our mainstay, with yields averaging 12.1t/ha this harvest. Wherever we have any concerns over black-grass, the land goes into spring barley – for several years if necessary.
“Our standard practice for the past 15 years has been to cultivate to 8-10” with our Solo as soon after combining as we can, having chopped and spread all the straw as evenly as possible. Typically, we have three quarters of our spring land ready for the winter before we start drilling OSR. Then, the only thing it sees before the drill in March is the sprayer for glyphosate.
“Having built-up our soil structure and organic matter levels well over the years as well as getting on top of black-grass, we’re now wondering if we could reduce the depth of our cultivation and degree of soil movement at drilling. Doing this could save us a lot of diesel and time while improving the resilience of our soils. But new kit is expensive. So, we want to find out exactly what – if anything – we stand to gain from any change and whether any savings and improvements would be sufficient to justify the expense.”
With his home-built Elita system continuing to a good job cultivating at 6-10” where soil conditions require it, Andrew Ward’s ideal would be to complement it with a machine working best at to just 1-3”wherever deeper soil movement isn’t necessary.
“The 75cm spacing of the legs on his Solo means Andrew currently has to work deeper than he would like to cultivate evenly across the whole width of the machine,” pointed out independent soils and tillage specialist, Philip Wright at the event.
“With every 2” reduction in cultivation depth typically reducing draught requirement – and diesel costs – by around 50%, shallower working would offer substantial savings in fuel and time here. It would also do much to decrease the vulnerability of the clay soil to trafficking damage; especially in conditions as wet as the land has seen this past summer.
“Digging down into the trial field shows the soil at depth is perfectly adequately structured, despite the areas of generally surface-based trafficking compression,” he revealed. “Since compaction from machinery diminishes with depth to a point where roots are well able to deal with it, even in ground like this with up to 57% clay, deep loosening should be unnecessary in most cases; especially as the ability of the soil to resist trafficking is built-up with progressive reductions in tillage depth creating a more naturally structured profile over time.
“In addition to effective stubble incorporation to overcome surface matting which can restrict moisture penetration and shelter slugs, cultivations in this sort of ground need to maintain aerobic activity to encourage effective bacterial straw breakdown. And they should be geared to eliminating any restriction to rooting within the top 20-30cm. Which means narrower spacing of tines – where needed – and lighter discs.”
Just like traditional ploughing, Philip Wright and Agrii regional technical adviser, David Felce are adamant that reduced tillage cultivation in the autumn has to produce ground that is both well set-up to weather down and well able to allow good water infiltration over the winter.
“This means you can produce the good seedbed with minimal soil movement at drilling which our Stow Longa work continually emphasises is the secret to the least possible grassweed emergence in the seedbed,” David observed. “Given the very much more limited herbicide options available, this is especially important in spring cereals.
“Your aim should be to give the clay its best opportunity to restructure with successive cycles of wetting and drying, freezing and thawing. Set it up with the clods that aren’t too big and a surface that is nice and even, and it will do so readily, leaving you with just the right conditions for spring sowing without further cultivation once the weather warms-up sufficiently.
“At the same time, though, you don’t want clods that are too small either – particularly where there is much in the way of silt in the ground. Otherwise you run the serious risk of surface slumping in heavy rainfall, or silt panning-out lower in the profile to restrict water and root penetration.
“It’s a delicate balancing act which depends on cultivating to the right depth for both the soil type and autumn conditions with the most appropriate kit set-up and operated correctly. Get it wrong at this stage and you’ll have to live with it the whole season – and into the next, if you’re not very careful.
“Equally important, of course, is to leave a nicely ridged surface through which water can readily percolate,” added David Felce. “After all, an inch of rain exerts a pressure of 100 tons/acre which can cause some serious structural damage if it doesn’t drain away rapidly.”
David, Philip, Andrew and Steve are looking forward to monitoring how well the different Glebe Farm trial plots overwinter, drill next March and, of course, yield next harvest.
Top 10 min till tips for heavy land ahead of spring sowing
Philip Wright and David Felce give 10 key tips for cultivating heavy land for spring sowing.
1: Use the combine as the first cultivator, chopping and spreading straw and chaff sufficiently evenly and well for the best incorporation, with stubble length depending on the drill to be used;
2: Cultivate as soon after harvest as conditions allow to give the maximum time for weathering and the greatest amount of grassweed germination ahead of sowing;
3: Examine the soil profile carefully in several parts of the field and set-up the machinery to remove any particular structural concerns;
4: Work only as deeply as necessary to loosen the upper layers of soil, leaving it to crop rooting to achieve any deeper soil structuring needed;
5: Only work the soil when moisture conditions allow the right degree of machinery penetration on the one hand and soil shattering on the other, and never when it’s in a plastic state;
6: Ensure sufficiently even and effective incorporation of straw, chaff and air for the most effective bacterial residue breakdown in the surface horizon;
7: Avoid mixing soil layers to maintain vertical fissuring and keep deeper buried grassweed seed out of the germination zone;
8: Choose, set-up and use cultivators to produce clods of the right size to weather down well without slumping – especially where there is significant silt content in the soil;
9: Leave a level but well-ridged soil surface that will permit effective surface water penetration over the winter as well as weathering down well; and,
10: Stay off the ground entirely until drilling – except for pre-planting glyphosate – moving as little soil as possible with the drill for the least grassweed emergence with the crop.