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Many will not automatically think about soil as a primary driver of farm profit, but it is your most important asset if your business depends on primary plants.
Soil must be treated a bit like a good working dog. Discipline is required to provide good nutrition and care.
The more of these you give, the more it will give you back and the more forgiving it will be if it is occasionally abused.
The quality and the condition of your soil heavily influence its ability to produce. Yes, there is really good land and not-so-good land, but both of them need to be well minded and kept in good condition.
Indeed, I think it would be better to have not-so-good land in good conditions than good land in poor condition and this can quickly happen. The yield from the land is a major factor in the generation of profit from farming.
So what does good condition mean? For me, it can be measured as structure and water percolation combined and I would put chemical fertility in second place until after it is restored to good condition.
Soil condition means the same thing, regardless of the type of farming being done, ie grassland or tillage. It affects different land uses in different ways, but the net effect is the same – good condition drives high output.
There are three major fundamental characteristics of a soil:
Most farmers are conscious of the chemical, some are conscious of the physical but the majority of land in the country is not optimised for either.
Chemical
This is the soil fertility complex which helps make essential nutrients available to plant roots to fuel growth. But nutrients have to be in balance.
There is little point in applying double the requirement of nitrogen and potash to drive growth where phosphate is deficient. The most limited nutrient sets the maximum growth level. It’s not rocket science and soil testing is the only way you can judge the relative availability of and requirement for each nutrient.
The same goes for trace elements.
A soil deficient in either manganese, magnesium, zinc or some other element cannot perform to its maximum.
It is a relatively simple process to add the deficient nutrient(s) in tillage, but grassland is more complex due to the interrelationship between nutrients and the animals’ requirement as distinct from the plants’ requirement.
An important component of nutrient supply in soils should be the whole mineralisation complex.
All organic matter contains a proportion of the nutrients required for its growth. These are released back into the soil by mineralisation, providing some organic matter is returned to the soil in some form.
But this has been happening less and less over the past few decades and the lowering of soil organic matter combined with low soil fertility and the low level of mineralisation all contribute to production levels that are below optimum.
Physical soil structure
Good soil structure is that nice physical break-up of a lump of soil if we drop it from a height. A worn or tight soil won’t break so easily into a good tilth.
Neither will it enable water to pass through easily, resulting in short-term surface waterlogging following rain.
This can be a serious issue for efficient use of grass. Soil structure is a natural phenomenon. We cannot make it but we can do things that will help nature to do it for us.
While these paragraphs are about soil structure, it is important to remember that structure is linked to the level of biological activity in the soil and they cannot be addressed separately.
Our soils naturally degrade almost every day of the year. Rain is probably our number one enemy, while for others it’s heat. Rain on bare soil continuously degrades natural structure, resulting in the crumbs being broken down to sand, silt and clay.
The finer soil particles (silt and clay) then get washed down into the soil pores, or air spaces, and they clog them up over time. This is partly why water percolation is reduced on worn tillage ground and intensively grazed grassland.
As well as making it difficult for water to percolate into the soil, reduced pore space also makes it more difficult for plant roots to grow and for natural root processes to take place. Pore space is further reduced by heavy machinery or even lighter pressures when the soil is wet.
Active soil biology is critical to reversing this natural process. But just as our bigger farm animals need to be fed, so do our small workers in the soil.
If they are not fed, they will not thrive and we will not get our soils naturally restructured. All forms of organic matter are food for soil biology.
Tillage farmers have become increasingly aware of the consequences of removing virtually all the organic matter on an ongoing basis, generally as straw and grain.
Livestock farmers will be less conscious because the grass has always been there. But as we get better at making efficient use of the grass we grow, by definition there is less being returned to the soil to feed it.
These soils may still read high in organic matter, but perhaps they do not have enough fresh food to maintain optimum activity to help provide good structure to keep percolation levels high.
Good soil structure means having the majority of the sand, silt and clay, of which it is composed, moulded into large particles called crumbs which are locked together by organic materials and natural glues.
The fine soil particles are consumed by burrowing earthworms along with organic matter, which is their food, and the excreted material is then the food for the smaller soil organisms that lock and glue it all together to form the crumbs.
Having good crumb structure to a depth means lots of pore or air space to enable water percolation, ease of root growth, air movement for plant and microorganism growth and water drainage.
Biological processes
As stated previously, biological processes are an integral part of a healthy soil. They contribute to the restructuring of soil which is always necessary due to natural and management practices.
Other processes continuously degrade the organic materials returned to the soil, including old roots, to release basic nutrients back into the soil to fuel the growth of either new plants or the soil biology itself.
This must be a continuous and cyclical process. This biology needs a lot of active feeding on a yearly basis. If the feeding doesn’t happen, then numbers quickly decline and their activity, which is central to a healthy soil, decreases.
Earthworms are very much at the top of this beneficial process. Different species do different jobs in different parts of the soil profile. They need to be present in high numbers, but this is not the case in far too many soils today.
How you treat your soil will influence how it treats you.
How many tillage fields can be ploughed nowadays with little or no birds following the plough because it is not worth their while? Indeed, how many permanent pasture fields would also not attract a feathered audience?
Soil biology is complex. We have some understanding of the essential restructuring work done by the myriad of soil microorganisms and also mineralisation.
But we know and understand little of the many other relationships that take place which may enhance growth either by the secretion of growth-promoting substances to the suppression of pests and diseases. We will probably only ever know a fraction of these interrelationships, but their net benefit is beyond question.
The benefits
Tillage farmers recognise the increasing cost of crop production over the past few decades and the escalating cost of chemical fertiliser.
We have been applying more, but getting little extra benefit. This is why it is so important to get our soils back into good working order.
A healthy soil gives higher crop output because it’s a better place for plant roots to grow.
Yield potential is helped by even the tiniest level of mineralisation during critical low-growth periods to help maintain our naturally high genetic yield potential.
And higher yield can frequently be done with lower fertiliser input because what is applied is more available to a plant root system because it can forage better.
Annual yield variability is also likely to be lower. Improved water percolation can help minimise stress in those high rainfall periods to enable growth to continue at critical times.
Higher humus levels help make the nutrient pool in the soil more available to growing roots, especially in times of growth stress.
And in the occasional drought, high humus and soil organic matter levels help crops through the moisture pinch to hold their yield potential.
All of these benefits add up to one thing – to ability to generate more profit through higher yield and some level of reduced costs.
Having these benefits in your corner is critical when the economics are tight. The problem is that these benefits are not instant.
They take time to evolve. But that’s no excuse for not beginning to take the necessary corrective measures now.
That means lime first. Then feed the soil with organic matter. And when that’s done, ensure that your fertility is optimised, because it’s then that the returns from applied nutrients pay real dividends.
Start the process now – you can’t afford to delay.
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