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If you put Quality In you get Quantity Out


Sean Spalding ArgonomistSean Sparling Argonomist talks about soil health


What is the current status of UK soils?

Soils are below par. Decisions taken over the past 20 years have resulted in cutbacks on vital nutrients, and we have some catching up to do. In particular, too many people took phosphorus and potassium ‘holidays’ in order to save money when indices were high and margins were low. Out of sight, out of mind, and now we’re seeing the consequences.


Are there any other reasons soil health has suffered?

Some farmers have preferred magnesium limestone instead of ground limestone or screened chalk to correct pH issues leading to high magnesium indices which can lock up the potassium, in turn severely limiting crop growth and development. Also, the decision to sell straw rather than return this vital source of OM, P and K back to the soil has been incredibly damaging.

In my opinion, farmers should not be growing crops for power stations. Where only the grain is removed from the field at harvest & the straw is returned, there is a "flux" of nutrients from soil to crop and back again - the problems with nutrient deficiencies come quickest where straw is removed - high levels of nutrient are stored in the straw and are therefore taken away from the labile pool. The problem with K indexes of 0 & 1, the small amount of additional material recommended by RB209 represents only 10-20% of the crops need, therefore it will be unable to make up for a low soil reserve if root growth is restricted by soil type, deficiency or seasonal conditions.


With such a successful harvest this year, why should farmers be concerned about soil health?

That’s a good question, however 20 years ago soils had an average index of 3; today they average around 1.5 and although index is not the whole picture, this is a worrying assessment of soils today. If we don’t change our management techniques, in 10 years I would predict an average index of around 0.5 to 1 at best. We cannot continue to take from the soil and not give back. A record crop is not a reflection of the sustainability of the soil - it’s more a reflection of a good growing season.


Can you offer some practical short term solutions to improve soil health?

I think it’s important to remind ourselves that the soil is the only reason we’re in business. Do not underestimate the importance of looking after it. Cover crops are a great option to add to a rotation. They are an easy, quick and very effective option that should be utilised. A good example is mustard, which fits with most current rotations and gives back more than it takes away, both in terms of nutrient and of vital soil organic matter.  


What are your thoughts on using FYM?

Obviously, FYM is the Holy Grail for improving soils, but there is simply not enough available. So we have to look at alternatives. I’m an advocate of ploughing within an ‘all round’ approach.  With the advent of minimal tillage techniques, crops are now expected to perform year on year within the same 6-8 cm of soil. Rotational ploughing allows for a fresh bit of dirt every so often - free from residual herbicides and freshly dug up. Working in a predominantly blackgrass area of the country, I would suggest each field be ploughed once every 5 years - this is also a vital tool in the fight against black grass.


How does ploughing control black grass?

I’m seeing blackgrass evolve, and it is now germinating from depths of up to 12.5cm (15 years ago 90% germinated in the top 2.5cm). It’s adapting, we’re seeing more seeds and more tillers. Ploughing literally buries the problem - and trials have shown that over five years up to 90% of the seed at plough depth will die. It shouldn’t be relied upon as the only solution but it certainly plays an important role in maximising crop production as part of the fight against this pernicious weed.


Do you think farmers need to be better educated?

Farmers are far more savvy today, and information has never been so readily available. But with so many regulations it’s important that they comply with the laws. We still have a lot of opportunities, and I think we all need to focus on the benefits of diverse winter and spring rotations, understanding the needs of both crop and soil, and utilising the new technologies that are on offer.


Can farmers be confident when using test results?

We’ve made tremendous progress with soil testing in recent years and GPS has been an incredible advancement for field management. However, it's the availability of the nutrient in the soil which is important - particularly with phosphorous.

Although soil analysis results are vital for good farm management, the importance of soil STRUCTURE is crucial. It’s worth remembering that:


Phosphate and Potash movement throughout the soil


What are your long term thoughts for improved soil health?

Inadequate soil reserves cannot simply be compensated for by the addition of a sniff of extra nutrient - growing crops take up much more than the basic recommended rates of K2O - upwards of 300kg/ha in some cases.

In the last 5 years I have seen an increase in different types of organic matter being applied to soils; such as poultry, pig and human waste, “where there’s muck there’s money” and all arable farmers should be seeking collaboration with neighbouring livestock farmers. Trouble is that numbers of livestock farmers are rapidly becoming fewer.


How do you see the future for soil health?

I think farmers will need to become far more knowledgeable, more accepting of new technology, and get back to true mixed rotations. As with any industry, we need to adapt and change to the conditions we work in. The wheat/rape rotation was never sustainable, and there are various crops that can be built in to rotations that massively benefit soils nutritionally and structurally, for example cover crops which leave more behind than they take away. We need to revisit the benefits of ploughing, to use fertilisers to our advantage, sample and map smaller areas in each field for better and more efficient application and utilization of inputs. I always go on the ratio of 20:80; the success of every farmer and agronomist is 20% skill and 80% luck - but without that 20% we’re doomed to fail!

We can’t control climate, temperatures, rainfall, world demand or currencies, so let’s work hard at excelling in the 20% control that we do have – that’s what will make the difference for a profitable and sustainable future.