Author: Oisin O'Murchu

Farmers have long known that healthy soil makes for healthier and more abundant crops.  This is important because of our need to produce enough food globally for a growing population, within a limited land mass.

But food production isn’t the only thing motivating an increased focus on soil health.  Increasingly, we’re learning about the soil’s ability to capture and sequester carbon, making it one of the most significant prospective tools in the fight to slow global warming.

So how does it work – how does soil capture and hold onto carbon?  And how can farmers meet growing demand for crops while still protecting this delicate natural process?  Let’s take a look.

What is carbon?

Carbon is the fourth most abundant chemical element in the universe.  It’s the building block for life as we know it, because it has the ability to form complex molecules like proteins and DNA.  Earth is a ‘closed system’ when it comes to carbon – we have a fixed amount, that never changes.  

How is carbon stored and released?

Most carbon on Earth is stored in the atmosphere and in rock, but a lot is also stored in living matter including live organisms and vegetation.  Plants and other organisms are always exchanging carbon with the atmosphere – this is called the carbon cycle.

Carbon dioxide (CO2) in the atmosphere is absorbed by plants as they photosynthesise.  This carbon is then stored in the leaves, trunks and roots of the plants or trees.  Living things eat the plants, and convert them into energy in a process called respiration, which generates CO2 as a waste product – this can be exhaled during breathing, or expelled in the form of other C02-based gases like methane, and goes back into the atmosphere.

When plants and other organisms die, the carbon they were made of is released as they decompose, and becomes part of the soil.  Decomposed vegetable matter from plants can eventually, after very long periods of time, be transformed by immense pressure into rocks and even fossil fuels, like coal. 

When we dig up or burn these fuels, large amounts of carbon get released into the atmosphere.  Carbon is also released when we remove vegetation, when we burn trees for fuel, and when we till the soil.

Why is carbon bad?

In short, it isn’t.  Without carbon, life on earth couldn’t exist.  Carbon dioxide in our atmosphere acts like insulation, retaining heat from the sun so that Earth doesn’t get too cold.  But too much carbon dioxide in the atmosphere intensifies this warming effect.  

Scientists estimate that since humans started burning fossil fuels during the industrial revolution, the average surface temperature on earth has risen by 1.8°F.  They are concerned that too much warming could have serious consequences for Earth such as a rise in sea levels, habitat loss and extreme weather patterns that could affect farming and food supplies.  

Under the terms of the Paris Climate Agreement, the global goal is to reduce carbon emissions and keep the average surface temperatures at no more than 3.7°F above pre-industrial levels.

How does the soil trap (sequester) carbon?

Many natural environments like forests, wetlands, peatlands and grasslands are referred to by scientists as ‘carbon sinks’ because they trap and store huge amounts of carbon deep underground.

During photosynthesis, plants absorb carbon dioxide from the air. They use sunlight and special cells called chloroplasts to convert it into glucose, which they use to help them grow, and oxygen, which they release into the atmosphere.  The carbon molecules remain stored inside the plant’s structures and when the plant decays, they are typically transferred to the soil.  

As plant lifecycles continue, old plants die and new ones germinate, feeding off the decaying plant matter in the soil.  In the upper levels, some carbon will always be exchanged between the soil and the plants or the atmosphere, but if the soil itself is left undisturbed, the stored carbon eventually percolates down to lower and lower levels where it can be locked away or sequestered for much longer.

Does carbon make soil more fertile?

Yes.  Carbon is the main component of soil organic matter and helps give soil its structure, water retention capacity, and fertility.  Soils rich in organic matter can support complex ecosystems including fungi and micro-organisms that are vital for strong, healthy crops.  These soils will have a defined structure that allows them to absorb and retain moisture, and move nutrients around effectively.  As well as supporting strong plant growth, this means that carbon-rich soils are less prone to flooding, wind erosion and other forms of degradation.

Carbon & no-till farming

Increased understanding of how the soil traps carbon and why this can be beneficial for farmers has led to a rise in the popularity of conservation tillage, particularly no-till.

For generations, farmers believed that the best way to keep soil healthy and get good yields was to churn it up before each planting to make it very friable, and apply lots of fertilizers – but in recent times, that thinking has begun to change.  It’s becoming accepted that while fertilizers may always be needed to support intensive farming regimes, less tillage helps the soil to retain these nutrients as well as moisture.

What is no-till farming?

No-till farming is the gold standard of conservation tillage because, as the name suggests, it’s built on the principle of not tilling the soil.  In no-till, the previous crop residue is left in place to decompose and a system of crop and potentially livestock rotation is used to manage soil nutrition in addition to the application of fertilizers.  

During planting, seed openers are used to cut a trench right through the previous year’s trash, into which the seed is planted and covered over with as little soil disturbance as possible.  This means that as much of the carbon as possible contained in the soil and in the plant matter is left in place, offering the greatest opportunity for long-term carbon sequestration.  Here are some benefits of no-till for farmers and the environment:

Soil structure is preserved

Plant roots, pores and capillaries in the soil structure are preserved so that the soil can more easily move moisture and nutrients around.  Fertilizers and rainwater are absorbed more readily, reducing the risk of soil degradation or erosion even in intensive farming cycles.

Micro-organisms flourish

Soil is full of micro-organisms from insects and worms down to microscopic fungi and bacteria that can be beneficial for crops.  When we don’t turn the soil over as in conventional tillage systems, these organisms can thrive – ensuring crops grow strongly, and capturing even more carbon in the soil.

Water is conserved

One of the biggest benefits of no-till is that it prevents loss of moisture from the soil.  Even when surface layers appear dry and cracked, in no-till systems you typically find that the subsoil stays moist for much longer than in conventional systems.  This can make crops much more resilient to drought.

Agronomic efficiency

Farmers running no-till systems can save significantly on fuel because they don’t till or cultivate the soil before planting or during the growing season.  They also save money on tillage parts and machinery.  No-till farming is a very time-efficient way of working, although it does require some careful thought and planning to make the system work effectively.

Other conservation tillage methods like strip-till, ridge-till and mulch-till are less effective at retaining soil structure and preventing carbon release, but they do help to slow the process down which has benefits for farm yields and the environment alike.

Looking for tools for your conservation tillage system?

Wearparts offers a wide range of tillage and planting parts compatible with all popular machinery brands and designed to give your no-till or conservation tillage system the edge.  Discover 30% longer wearlife and guarantees against breakage for efficient planting and less downtime – find a dealer today!

As farming practices go, crop residue management is a relatively new concept.  While many aspects of tillage farming have barely changed in centuries (save for advances in technology), it wasn’t until the 1960s that farmers began to make the connection between their operations and the erosion or degradation of the soil.

This eventually led to the adoption of no-till farming practices and other conservative tillage methods, including the idea of using crop residues to protect and nourish the soil.

A large percentage of farmers now practise some form of residue management on their land, and as a result, these methods – and the tools to support them – have become much more refined.  Let’s take a look at the different types of residue management, and what’s available to help farmers manage these processes more efficiently.

What is residue management?

When we talk about residue management, we are usually referring to the deliberate management or use of leftover stalks, stems, leaves and other vegetation left behind when a crop such as corn, barley or wheat is harvested.

However, residue management can also refer to cover crops – crops that are planted for the sole purpose of protecting the soil.  

In both cases, the vegetation plays an important role in protecting the soil from wind erosion, promoting moisture absorption and preventing surface water runoff, and enhancing the soil structure together with its roots. 

At  a certain point in the life cycle of these plants, they will then be plowed into the soil where they decompose, enriching the soil with organic matter and nutrients.

Sometimes, chopped residue such as straw is left lying on the soil surface.  This process is called mulching.  Mulch is often used as cover for emerging seedlings, protecting them from extreme weather until they become established.  The mulch decays over time, providing organic matter for the soil.

What are the main types of residue management?

Residue management is carried out as part of a wider tillage system.  In a no-till system, more than 30% of the soil is covered by residue.  In conservation tillage – such as strip-till or ridge-till, between 15% and 30% is covered.  Conventional tillage systems leave less than 15% of the soil covered by residue at any given time.

No-till systems

No-till farming involves planting crops directly into undisturbed soil, with residues from the previous crop left behind to protect emerging seedlings and maintain the structure of the soil.  

No-till systems depend on the use of very precise, sharp planting blades that can effectively open a clean furrow by slicing down through surface trash.  If the blades are dull or not angled correctly, hairpinning can occur.  This is when trash gets pushed down into the bottom of the furrow, allowing air to get trapped and preventing good seed-to-soil contact, which can lead to poor germination and disease.

Conservation tillage

Also known as reduced tillage, conservation tillage is the collective term for a number of different practices that aim to retain more surface residue for the benefit of the soil.  Farmers may use one of the following processes:

Strip-till

Strip till is where the land is tilled in alternating strips.  Where crops are to be planted, the residue is plowed in.  But between rows, the soil is left undisturbed with the residues intact. The following year, the strips are switched over so that each planting cycle, half the field is left undisturbed. Strip tillage is popular on challenging soils where no-till might not be practical.  The process itself is usually carried out using a strip-till rig with a combination of ripper points, coulter wheels, fertilizer knives and other soil conditioning blades.

Ridge-till

Ridge tillage is often used for sloping sites, but can be implemented in almost any conditions.  The land is initially tilled to create evenly-spaced ridges that sit 4-6 inches above the level of the soil, with furrows in between.  The tops of the ridges are more aerated and warm more quickly than the furrows.  Crops are planted into the ridge, which gives them an advantage over any weed seeds that germinate in the furrow.  

Following harvest and over winter, residue from the crop is left on the surface.  In spring, only the tops of the ridges are tilled and reshaped before planting.  Ridge tillage has the disadvantage of needing specialist ridge-tillage machinery for cultivation and planting.  Residue on the ridge top may be removed altogether using a ridge cleaner, or chopped using blades set to a very shallow depth – sharpness is vital so as not to damage the shape of the ridge.

Mulch-till

Mulch tillage is another technique for residue management.  Instead of plowing residue into the soil, in mulch tillage the subsoil is tilled using deep implements like chisel plows to break up compaction, while the surface of the soil – and any vegetation or stubble on it – is left relatively undisturbed.  Mulch till is regarded as a conservation technique because it leaves at least 30% of the soil surface covered by trash; however it involves tilling 100% of the subsoil, which can still leave the soil vulnerable to wind and water erosion.

Cover cropping

Cover cropping is also sometimes referred to as ‘green manure’.  Cover crops are planted with the sole purpose of covering the soil, rather than as a cash crop for harvesting.  The most common cover crops are legumes, which are part of the pea family – these include alfalfa, peas, beans and lentils.  Legumes are known for their high nitrogen levels, which they fix into the soil, reducing the need for chemical fertilizers.  Legume crops also help to eliminate soil bacteria and enhance biodiversity, forming valuable ecosystems that help to further enhance soil quality in the long run.

Cover crops are usually plowed into the soil before the plants reach maturity, although sometimes they are used as fodder for grazing animals who eat the vegetation and then condition the soil with their waste.

What are the benefits of residue management?

The benefits of effective residue management have both environmental and financial benefits for the farmer.

Erosion prevention

As previously discussed, the primary benefit of crop residue management is its ability to protect the soil from wind and water erosion.  The presence of stubble on the soil surface prevents dry soil from blowing or being washed away during extreme weather conditions, especially in winter.

Moisture retention

However, crop residue management also has important benefits for overall soil quality, too.  Leaving residue behind after a crop is harvested means that the roots of the plant are still intact, which preserves the soil structure and prevents it from becoming compacted.  This means that moisture can penetrate more easily, and can be stored in the pores of the soil which reduces surface waterlogging and runoff.

Nutrient cycling

As the residue decays, the nutrients stored within it are released back into the soil.  Fibrous material decomposes into humus, which is a rich source of nourishment for subsequent crop plantings.  Humus-rich soils retain heat more effectively, so they warm up faster in spring and stay warmer for longer during the growing season.

Weed suppression

While decaying crop residues can promote growth, stalky crop residues on the surface can help to inhibit the growth of weeds by preventing seeds from germinating.

Sustainability and efficiency

Crop residue management systems like no-till and strip-till also have environmental and financial benefits.  The less the soil is disturbed, the more carbon it can sequester, which is one way farmers can help slow down climate change.  Reduced tillage systems can often open a furrow, fertilize and plant in a single pass, which vastly reduces the cost per acre and maximizes farm productivity.

What planting and tillage tools are used for residue management?

Crop residue management requires the use of a range of different tillage tools and implements depending on the system being used.

1. Seed opener blades are used in all systems for opening a seed furrow and planting the seed.  In no-till systems, it’s vital that seed opener blades run true and stay sharp so they can effectively slice through trash and open a clean furrow with no hairpinning.  Wearparts seed opener blades are triple heat treated with a longer bevel that stays sharp for up to 30% longer than the OEM equivalent, with a lifetime guarantee against breakage.  We test all our blades in-house to some of the tightest tolerances in the industry, ensuring precision planting even in dry soil conditions.

2. Coulter blades and high-speed compact disc blades may be used in strip-till operations to prepare a seedbed before planting.  Again, sharpness and durability are of paramount importance, enabling the farmer to cover more ground before the blades need to be replaced.  Our boron steel blades are designed to wear more evenly and last longer than any other blades on the market – plus we’re the exclusive United States distributor of Serbian-made, globally renowned FKL bearing hubs to help you get the best possible performance from your blades.

3. Ripper points and chisel plow spikes are used in mulch-till operations for subsoiling.  This is deep, heavy-duty work that demands superior components with the longest possible wear life.  We offer custom hardfacing on many of our ground-engaging components, and we also source our ripper points using high-chromium white iron for additional strength and aggressiveness.

4. For ridge tillage systems, our cultivator sweep blades can be used for mechanical weed control.

Want to find out more?

If you’re thinking ahead to fall planting or even next spring’s crop residue management, and you’d like to know more about how Wearparts can make your operations more efficient, get in touch – or locate your nearest Wearparts dealer.

Much of America’s Midwest is currently experiencing a prolonged dry spell, with below normal precipitation and above normal temperatures resulting in worsening drought conditions.  

According to the USDA’s drought monitor as of mid-June, parts of Nebraska, Kansas, Missouri and Texas were experiencing severe drought conditions with over 50% of the country’s corn and soybean crop currently growing in drought areas.  

Even some storms with heavy rainfall have failed to make much difference in the driest places, which begs the question – is drought going to be a regular feature of US farming in the future?  How bad could it get?  And what can farmers do to mitigate against dry conditions?

Let’s take a look at farming in drought conditions – how to maximize soil moisture, what the options are for irrigation, and what the future of farming might look like as a result of ongoing climate conditions.

What can farmers do about drought?

There’s nothing a farmer can do to make it rain – but there are many steps farmers can take to address the problem of low precipitation.  These include measures like artificial irrigation, soil enhancement, erosion prevention and careful crop selection.  It’s worth noting that in extreme drought conditions, finding enough water to irrigate crops can be a challenge. Let’s take a look at some of the measures in more detail.

What are the main methods of soil irrigation?

There are lots of different methods of providing water to dry soil during a drought using irrigation systems.  Some systems – such as overhead sprinkler systems – are high cost and high-tech, and most often used for specialized crops with low drought tolerance.  Other methods are more cost effective and easier to apply across large acreages, like some of these tried and trusted methods:

Surface irrigation

Surface irrigation methods are some of the most traditional and involve simply flooding water onto the surface of the soil and allowing it to absorb.  Methods include furrow irrigation and border irrigation, where water is diverted into soil ‘troughs’ so it can’t run off before being absorbed.  Surface irrigation is low tech so it can be used on very large acreages, but it requires a lot of water, and doesn’t deliver targeted irrigation to the plant.

Center pivot irrigation

Center pivot irrigation is used for large farms because it can cover big areas efficiently.  A sprinkler system is mounted on wheeled towers which roll in a circular pattern around a central ‘pivot’, which is the water source.  Plants are then irrigated by the overhead sprinklers.  These systems have led to the emergence of circular crop fields all over America, although they can be adapted for rectangular fields.

Drip irrigation

Drip irrigation is when a farmer runs a network of pipes or tubes through a field.  The pipes have holes that drip feed water close to where the emerging plants are.  This system is relatively low tech and low cost, and delivers targeted moisture directly to the plant so it uses less water.  However, it may not be practical to use across very large areas.

Micro sprinkler

Like drip irrigation, micro sprinkler irrigation involves the use of a pipe network but instead of dripping out of holes in the pipe, the water is delivered through a series of small sprinkler attachments.  These provide a very fine spray of water that is precisely targeted to the plant, making them very water efficient – but not very cost-effective across large acreages.

Sub-surface irrigation

Sub-surface irrigation is similar to drip irrigation except that the pipes for delivering the water are buried underground.  This has some big advantages in that the moisture is delivered directly to the roots of the plant, and also because evaporation is kept to a minimum because the water is applied below the surface.  It’s not very high-tech, but can be disruptive to install and requires careful monitoring to ensure soil does not become waterlogged.  Care must also be taken not to disturb or damage the pipes during future planting cycles.

What are the alternatives to soil irrigation?

Artificial soil irrigation methods aren’t always very practical in modern day crop farming.  The vast acreages involved make watering plants via a network of sprinklers or pipes very expensive.

Instead, farmers must look for ways to preserve the moisture that’s already in the soil so that plants have the best possible chance of survival, even when it doesn’t rain for long periods.

How can farmers conserve soil moisture?

In order to retain moisture in the soil, it’s important to preserve both the structure and the content of that soil.  The more organic matter soil contains, the better it is at absorbing and retaining moisture.  Undisturbed soil has its own structure – a complex network of channels that allow moisture and nutrients to be moved around and stored.  Preserving the soil in the best possible condition is the key to preventing moisture loss.  Here’s a look at some ways farmers can optimise soil condition:

No-till systems

In no-till systems, the soil is not plowed or turned over, so its natural structure is preserved. This means that all the tiny pores and channels in the soil that are used to store water remain intact, and can be accessed by the roots of young plants.

Cover cropping

The pressures of modern farming have led to the ‘supersizing’ of the industry – it’s more economical to farm vast swathes of land using huge 100ft machines that can do more work in a single pass.  But these practices have meant the loss of natural hedgerows, woodlands and other windbreaks that are not only important for biodiversity, but also for moisture conservation.  A field surrounded by tall trees has its own microclimate – natural shade slows the evaporation of moisture, while tree canopies stop the wind from carrying away moist air.

Selecting crops for dry climates

One of the best things farmers can do to mitigate for drought conditions is grow crops that are naturally adapted to dry conditions.  These types of crops will require less irrigation and be less vulnerable to pests and disease.

Crops that cope well with dry conditions typically have deep roots that allow them to access moisture locked away in lower soil levels.  Science has led to the development of new varieties of staple crops like corn and soya that are better adapted to drought conditions.  But there are many crops that are naturally able to cope with dry soils, and many believe we should be looking into these as a more sustainable food source for the future.

These crops include cowpeas (black eyed peas), sorghum, alfalfa and groundnuts.

What to do if you are concerned about drought

There isn’t anything farmers can do that will prevent a drought or make it rain.  But there are things you can do to be better prepared, and to sustain their farms through prolonged dry periods.

• Farmers don’t need reminding to keep their eye on the weather forecast – but it’s also worth keeping your finger on the pulse of the USDA drought monitoring system.  You can register to submit data from your own farm that helps meteorologists understand precipitation and drought patterns better.  It’s hoped this information will allow farmers to predict when future droughts will occur and act accordingly.

• Make sure you are aware of any available government support and compensation programs relevant to drought.  You may be able to access financial support for irrigation systems, or claim against losses of livestock and/or crops due to excessively dry weather.

• Work with your fellow farmers.  In many drought-prone states, farmers have formed water-sharing collectives or made arrangements with neighboring farms to share water resources.  Remember, a little water can make a big difference – collaborating with others can optimize water allocation and reduce individual risks.

Looking to the future

If you’re considering switching your farming system to a conservation or no-till method to conserve water, Wearparts can help.  We offer a wide range of replacement tillage and planting parts developed specifically for no-till systems, that can help you work the soil efficiently without damaging its natural structures.  Get in touch to find out more.