Your soil, millions of years in the making.

The new seasons crops are in the ground, or in the process of going in, some of it has been drilled in haste after a long protracted period of wet drizzly conditions resulting from a drawn out harvest. Although the conditions weren't as bad as in 2007, never the less, soil conditions weren't great with quiete a lot of compaction issues resulting from heavy machinery trying to get the crops off before they went flat. Now this is probably not the case in most counties east of the M5 where a lack of moisture is more of a problem and having enough moisture to get the new crop to germinate is the pressing issue.

When I was farming in Zimbabwe, moisture retention, deficit irrigation, minimum tillage, trash incorporation, controlled traffic, were all tools we used to boost the water holding capacity of our soils, along with a very active soil testing regime to monitor lime, organic matter, and P&K's. The Agricultural Research Trust Farm (ART Farm as it was known) sponsored by the Commercial Farmers Union and other producer groups, was way ahead of it's time in carrying out research and testing techniques to boost grain production in a way that boosted the bottom line on the balance sheet, rather than pure out and out yield. The attention to detail was scary, something we struggled to get our heads around at the time as we saw it as a huge burdensome amount of paperwork and record keeping. However, they could tell you to the nearest cent how much a field of maize, soya, grass, etc, had cost to grow, how much it had produced and what the margins were over a wide range of parameters. This wasn't a small little research unit either of 50 acres either, but a commercial unit. There was focus, right from the very top, all the way down to tractor driver level on getting the basics right.

The soils we farm with here in UK aren't wildly different to some of those I farmed in Zim, some of the red clay loams around Crediton, or parts of Shropshire are similar to the best soils we had, however most of our soils would be classified as green sands, or vlei sands as we called them, grade 4 and 5 stuff. Easily compacted, very little organic matter, easily capped and really easily eroded in heavy rain. We had contour drains on all arable ground with a gradient steeper than 1 in 50 just to control  erosion, as well as manage moisture retention. In the USA and Canada, they call this strip farming and can be seen clearly in the photo below.


Photo by Tim McCabe, USDA Natural Resources Conservation Service

So why do we not see the same level of care of soils here in the UK as in other parts of the world?


Photo by Rodney Burton, Wigborough, Somerset.


Land near Launceston

The maize harvest is going great guns now, some of it is fit and some not quite ready. Soils vary in the amount of moisture in them, but with the cooler weather, there is less evaporation and drying out taking place, so even small showers are keeping some areas saturated and making traveling conditions difficult with harvesting machinery resulting in deep ruts and compaction areas being created. So all the sponginess will have disappeared in these areas, less air in the soil, less absorbtion capacity, poorer rooting potential for the following wheat crops where going in, as running a ripper tine through wet soil has little benefit and will lead to greater soil slumping in the spring. A deep hard frost would do more to restore some structure than a tine. Most farmers will be ploughing these spots in the hope that this will help, however in my experience this just results in the compacted blocks being inverted with little restoration of structure and doesn't solve the issue of the deeper compaction problems. Really, these can only be tackled after harvest next year, you just have to live with the consequences of this late maize harvest and possibly look at better, lighter, south facing, sheltered fields for next year.

Maize under plastic has done well for a few people in the past, it does enable you to harvest 2-3 weeks earlier than normally, although it is questionable having seen data that you get a heavier crop with more starch than conventional maize. If you are reliant on using this type a system to grow maize, you really do need to look closely at this picture taken last year in March in Devon showing the amount of plastic still littering the field. This plastic is NOT biodegradable, it is PHOTO degradable, meaning it needs sunlight (ultraviolet light) to help it degrade, rather like clear PVC pannels in rooves that break down over time and become brittle. It does not however completely disappear, all that happens is that these 'squares' of little bits of plastic disintergrate into ever smaller pieces down to microscopic level, but they never fully decompose. We have this very same situation on coast line beaches which are becoming ever more contaminated with plastic. The issue is this, your soil is your lifeblood if you are a farmer, allowing it to become contaminated in a relatively short time period of one generation, compared to the millions of years it has taken to form, is folly. What will happen in 10 years time when these microscopic particles start to filter through into water courses and the water table. Already the Environment Agency are stepping up their surveilence teams and monitoring closely waters in catchment sensitive areas, for runnoff and siltation, we know water companies are looking at phosphate levels, not just nitrogen polution and metaldehydes. There are better forms of plastic out there that are properly BIOdegradable, that break down completely, the best being that made from maize starch which has a fertilising effect as it does so, but which was discontinued some years ago as the cheaper photodegradable stuff was promoted. The better stuff costs more, as you would expect, the question you need to ask is what is the long term viability of your farm soils if you are totally reliant on short term solutions?

And since we are talking about lifeblood, how many farmers are soil testing regularly, accurately and correcting the issues as they arise in a timely manner? Below is an example of the type of pH soil testing I do, the importance of this method was drummed into me by R&T Agricultural Liming, long before the likes of other companies that went on to develope an electronic method using computer software to predict and interpret soil tests and plot them in multicoloured maps.

Finding and correcting areas of low pH is vital in getting the best out of inputs and maximising yields through efficient use of inputs, especially fertilser and sprays. It is amazing how much soils vary within fields, especially in areas where soils are traditionally expected to be alkaline, like over Cotswold brash type soils, or clay caps over chalk downland, or where light shillit types run into heavy Dunsland/ Lyas blue type clay. Correcting the areas where there are deficiencies, not just blanket coverage is obviously cost effective and lessons the risks of over liming and locking up major and minor trace elements.

The result of not having a regular lime testing and spreading program results in test results like this above. When you start getting results like this in the very low 5's, it takes a very large amount of liming material to correct the deficit and cannot all be aplied at once either, but needs to be spread out over a couple of crops. It's is also important to remember the pH scale is a logorithic scale, meaning it is exponential in the amount of corrective material needed to address the problem.


Spring Barley near Bodmin struggling on a pH of 5.6 in 2009

 Too much lime can also be an issue, something I see particularly on dairy units that are using seasand as bedding in cubicles, which then gets pumped out in the slurry onto the fields usually closest to the unit. I am seeing pH's in the very high 7's and low 8's in parts of Cornwall with trace element lock up really becoming an issue. I have had a number of farmers saying that their pH's are good, yet their grass is analysing low in calcium when they do tissue analysis. Having tested and found these pH's up near 8, gypsum then becomes about the only way of boosting Calcium availability without raising the pH. A lot of work has been done on this not only here in the UK, but all around the world, however I have yet to come across an agronomist with any major company that knows anything about it, the only one I have come across is Jo Scammel who does a lot with Dairy farmers in Gloucestershire and who runs the soil clinics at the dairy event.
With the push for bigger dairy units, one has to ask what the long term consequences of very high concentrated levels of slurry will be on the micro organisms in the soil profile on these units. For sure, every arable farmer in the east would probably gladly want a dairy farmer next door where he can rotate, or share field rotations with so he gets organic manure back into his soils. In the last three years I have managed to demonstrate to a number of cereal growers just how important chicken muck is and how putting back organic matter into the soils where continuous wheat is being grown is vital in maintaining yield and grain quality. On one unit in particular we have taken average yield from 2.6t/ac in years 2006-2009 to over 3.7t/ac this year. It has been interesting to physically see how the soil structure has changed, it is far more friable, works easier, doesn't cap so easily straight after heavy rain, nor does it slump as much during the winter. With the addition of using Nickerson original seed too, there are no big bare patches where there is nothing growing like there used to be in the past as the wet areas don't compact and slump like they used too and the film coated seeds allows faster, bigger root systems to develope quickly to take advantage of the nutrients on tap making winter kill less of an issue, even though last year was one of the coldest in a very long time.

However we have a few cases now developing of the opposite starting to occurr, very large dairy units with very high stocking rates/ac (3+ cows/ac) as the animals are housed most of the year round. That means there is a lot of slurry to spread on quite a tight area of ground, with the result that the ground is being drowned in slurry, literally. Lots of dead worms littering the top soil, large bare patches developing in between grass plants where they have been suffocated by slurry, sward quality and grass yields falling as a result. Sward lifters, slitters and slotters can only do so much in the short term to alleviate these issues, the longer term damage is the more worrying problem that is being stored up for the following generations.

We need to start looking at farming in a much more holistic manner, indeed Allan Savoury who conducted trials in grazing and land management first in the Karoo many years ago in South Africa and subsequently has started a foundation in the USA following extensive work in Texas and other ranching states has laid out some key principles in this area. I would recommend farmers read some of his work, or look at this website http://www.holisticmanagement.org/ especially those in drier parts.

We are all players in the food chain, whether consumers, or producers. We need to ensure that we look after our primary resource, the soils we grow our food off.

If you eat, you are involved in agriculture.