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Transitioning to more regenerative regimes hasn’t been entirely plain sailing for three growers with very different soils and situations who shared their experiences at a packed Agrii Green Horizons seminar at this year’s Groundswell.

All three no-till novices have found their journey over the past 6-8 years very positive and are increasingly profiting from moving less soil, protecting its surface, keeping roots in the ground and diversifying their cropping. While their goals are very similar, the way the growers have gone about achieving them reflect clear differences in the balance each has to strike between long-term sustainability gain and short term profitability need. On his mostly light 160ha at Hawkmill Farm just to the east of Cambridge, David White’s principal stakeholders are his family. This and his determination to‘ wean himself off the comfort blanket of cultivation as soon as possible’ led him to switch from full to no-till in a single, bold step in 2015.

Since then, he has been experimenting at scale with a whole host of regenerative opportunities, including a vast range of cover cropping mixes and management methods; early drilling and a variety of OSR companion crops to combat cabbage stem flea beetle; and, most recently, bi-cropped beans and oats –both winter and spring. At Revesby Estate near Horncastle in Lincolnshire, farms manager Peter Cartwright has been moving more steadily but very deliberately towards no-till across the Wiggins-Davies family’s1100 cropped hectares since 2014.Getting the basics working correctly, keeping things simple at the start and building on carefully trialled experience with a firm goal in mind has been his recipe for success to meet the business’ need for parallel improvements in profitability and sustainability. 

“We have been surprised at how quickly soil biology can start working much better when you look after it and encourage it to proliferate. Working with nature rather than trying to force the soil with big, heavy machines has seen our soil structure and health come on by leaps and bounds. “Amongst other things, both shallow working and deep burrowing earthworm numbers have built-up really rapidly. Keeping the land green the year round with catch and cover crops has been very useful in capturing nutrition. And drilling directly into them with the least possible soil disturbance has also helped capture carbon.

“We are finding many ways to farm both more sustainably and profitably. The bi-crop of spring oats and spring beans we tried last year, for instance, performed handsomely with no in-crop herbicides, fungicides or fertiliser at all. The two species complemented each other extremely well, generating a much higher margin than the traditional beancrop we grew alongside it. “Higher seed rates and the right soil structure mean we are increasingly able to employ crop competition in place of herbicides to deal with weeds,” David added. “We need much less tractor horsepower these days, and work our tractors for around a quarter the time we used to. This means they last longer and we at least halve our diesel usage. “Our soils are far more resilient to both drought and heavy rainfall too. At the same time, the amount and diversity of wildlife we have on the farm these days is a joy to see.”

Since moving from minimum tillage with rotational ploughing to almost entirely no-till cropping over the past eight years, Peter Cartwright has also seen huge improvements in the workability, resilience and health of soils with up to 40% clay and 40% silt at Revesby Farms. Over this time, he has almost halved diesel usage and substantially reduced labour needs while increasing average wheat yields by 1t/ha; not to mention getting to grips with horrendous blackgrass problems. “Our transition was actually prompted by the need to deal with levels of blackgrass that made some of our land almost uncroppable,” he explained. “Following the Stow Longa recipe, we introduced up to three consecutive years of spring cropping, concentrated on moving as little soil as possible at drilling and employed the most competitive wheat varieties at high seed rates drilled as late as possible in the autumn.

“The rotational change led us to trial a range of cover cropping options and we now grow around 450ha of winter covers a year. We first ventured into direct drilling with a tined Horsch Sprinter, to which we have just added an Avatar drill now our soils are in good enough condition. We trialled the prototype Avatar back in 2016 and knew this would be ideal for our needs once we were in a position to make the most of its disc coulter system.”

Two different types of direct drill these days gives the Revesby team the flexibility they need to deal with different soil conditions, trash levels and the weather. Over 90% of their crops are now drilled without cultivation, and the capacity to drill all their winter wheat in5-6 days reduces both their weather risk and need to travel when the conditions aren’t right. Alongside moving the least possible soil under the most favourable ground conditions, moving to their own version of Controlled Traffic Farming has made a big difference to the physical as well as biological health of their soils. “Everything is coming together so well now that I think we should be able to push our wheat yields up another 1t/ha over the coming four years,” suggested Peter Cartwright.

“With hindsight, we should have been braver and cut down our cultivations sooner. And we certainly shouldn’t have invested in the Horsch Cruiser cultivator we have hardly needed to use since the day it arrived because our soil condition improved so much.. “Getting the basics of both drainage and black-grass management right before moving too wholeheartedly into no-till have been essential to our success. A shave been attention to detail, working towards a clear goal, and careful trialling under our own conditions in a scientific way as an Agrii Technology Centre.”

Improving drainage and soil structure to enable the most successful direct drilling have been as important in the Fraser family’s transition from traditional plough and min till cropping to the regenerative regime they now employ on more than 80% of their farmed l and. They are also being able to successfully extend this experience to their contracting operations to provide the resource and experience needed to help more West Country growers benefit from soil-first management. “We have found digging soil pits everywhere to assess soil condition and carefully targeted low disturbance subsoiling and mole-ploughing to sort out any inadequacies a crucial first step,” George Fraser stressed. “With our agronomist, we also plan everything on the basis of full soil testing, repeated every four years to monitor changes.

“We really benefit from being large enough to run several different types– including a Weaving GD, Amazone Cayena and Weaving Sabre Tine – so we can match the kit we use closely to soil needs and condition. The substantial slurry, muck and digestate service that is part of our family business has been great fit with our organic matter-building focus too. “Contract farming means we can’t afford to be evangelical about our system. So, where ground needs subsoiling it gets it; where trash causes slug problems we stubble rake; and everything we put into our cover crops is there for a particular economic as well as environmental reason. “Like David and Peter, we have seen great improvements in the health, vitality and workability of our soils in a relatively short time without compromising crop performance,” he reported.

“Wider rotations are giving us more flexibility to adapt to conditions as well as greater biodiversity. Cover crops are helping condition soils and build organic matter while providing late-season wildlife food and shelter. And better plant health through healthier soils and more balanced nutrition is taking the pressure off sprays programmes at just the time we need it with the loss of so much chemistry. “Moving to no-till is far from a panacea and it’s all too easy to make mistakes; especially where them likes of bromeas well as blackgrass are problematic. But we have no doubt that integrating the most appropriate regenerative techniques into our business with attention to detail and the best-informed advice has to be the way ahead.”

Martin Lole of Springfield Farm and Mzuri, reflects on drilling into stubble and his recipe for successful
straw management.

As farming systems become more productive, arable enterprises are faced with increasing levels of straw to manage post-harvest. For many this provides a valuable secondary income source when baled, but for others, whether through environmental objectives or simply not having the demand for it, straw management forms part of the preparation for next year’s crop. Some growers may see leaving straw in the field as a luxury or perhaps a nuisance depending on their system, but when managed well, there are a number of advantages with wide ranging benefits from soil health to better establishment.

Advantages of drilling into
stubble:

• Provides nutrition for soil microorganisms, supporting healthy populations

• Increases soil organic matter

• Reduces risk of wind and water erosion by protecting with a straw thatch the upmost field surface from harsh weather

• Supports good soil structure and promotes better machinery travel

• In dry seasons, stubble can help to preserve moisture by retaining it in the soil

Talking predominantly about direct establishment systems, drilling into stubble can be a very effective and efficient way to establish a range of crops, but success in doing so can depend on several key management factors which are important to consider before heading in with the drill.

1. Assess your straw

“You’ve had a bumper harvest and with that comes a bumper crop of straw. You recognise the benefits of leaving the straw on the surface but what next? ”The most important factor relating to successful direct drilling into straw is ensuring an even spread and a chopped to a consistent length. By far the easiest and most cost-effective way to achieve this is to start with the combine. Watching to see if straw is chopped and distributed evenly will highlight whether the combine is operating as it should, or whether further preparation is required prior to drilling.

Uneven straw distribution will cause problems with variable germination and can cause drills to block if not managed correctly, something which can cause unnecessary downtime and frustration. This leads onto considering what type of drill will be used and what the operator wants to achieve by drilling into stubble. For farmers wanting to drill into a lot of surface residue, strip tillage has the advantage with wide row spacing and sufficient clearance for trash flow, something which the Pro-Til range has been specifically designed for. For those growers who still want to drill into stubble but want a hybrid system that gives a more conventional row spacing, covering large areas quickly, good straw management is particularly important. The iPass sits in this category, offering conventional row spacings into stubble, min till or cultivated land whilst maintaining high forward speed and accurate seeding which makes the iPass range a versatile solution for a range of drilling situations.

2. Manage uneven straw

“Your combine wasn’t what it was and refuses to chop and spread straw consistently, what now? ”For effective drilling, chopped straw should be short in length and evenly spread across the field. This not only provides a smooth canvas for direct drills to operate in, but it also starts the process of decomposition and returning those nutrients back into the soil. There are a number of methods of pre-drilling field preparation that can be used to manage uneven straw levels including raking with a stubble rake such as the Mzuri Rezult. Fitted with discs and five banks of stiff tines, a pass of this surface cultivator can help to chop surface straw, spread it evenly across the field and also generate a small level of tilth mixing it with the straw to aid decomposition. 

For growers who want to maximise the incorporation of chopped straw with the top layer of soil, there are various surface cultivators for example the Vaderstad carrier which will produce more tilth than a stubble rake, but will leave a very even finish of mixed soil and straw –accelerating straw decomposition which can be an ideal canvas to drill into with a direct drill, particularly if there is a large amount of surface straw to deal with.

Not only does lightly incorporating the straw prepare the field for drilling, but it can also act as an important step in minimising slug and weed pressures for the next crop. The Mzuri Rezult rake can be used in the heat of the day post combining of OSR stubbles to disrupt slug habitats and expose slug eggs to the midday sun reducing slug pressure for the following crop. Raking can also encourage volunteers and weed seeds to chit by mixing them with a slight tilth which creates a stale seed bed that can either be harrowed again for cultural control or receive chemistry both providing a blank canvas ahead of drilling.

3. Success with straw

“You’ve taken the time to assess your straw and carried out light surface cultivation in fields that need it, giving the direct drill operator the perfect recipe for success. ”When managed effectively, working with surface straw can yield great benefits over traditional establishment methods. Not only does it provide a weatherproof finish which helps mitigate erosion and run off in high rainfall, it can also provide a sheltered microclimate for young seedlings when drilled between stubble rows. Stubble acts as a mulch to preserve soil moisture and prevent it drying out in dry seasons, reducing stress to the crop and protecting long term soil structure. All of which benefits crop growth throughout the season and ensures a stable, consistent environment to direct drill into. Some direct drills may require more stubble preparation than others depending on what the operator is  trying to achieve. 

The Takeaway Message

Not all stubble is created equal. Low volume stubbles such as Rape, Bean sand wheat straw that has been baled are all very straightforward for the majority of single pass drills. However, larger volumes of straw on the surface can cause challenges particularly for drills with close row spacings or low frames with little clearance. When combined with heavy soils, these scenarios can prove even more challenging and effect the success of the establishment. There are however a few important steps that we can take to balance the benefits of drilling into stubble with the need for effective seeding. Straw raking or light discing is always going to be a helpful tool when dealing with high volumes of surface straw, as is also avoiding drilling into heavy soils when wet. It is also important to consider the drill being used and its clearance, stagger and row spacing. But perhaps the most important thing to take away, is the importance of starting straw management with the combine. It is essential to ensure a short stubble length and if not baled a well chopped spread of straw to give the best canvas ahead of drilling.

By Andrea Basche, Assistant Professor in Cropping Systems, Source: University of Nebraska Extension

With growing interest in cover crops, it is important to understand how cover crops might impact soil fertility for the following cash crop. Nitrogen (N)provided by cover crop biomass may be used in the short-term by the following crop, and in the long-term through improving soil N content and reducing fertilizer input costs. The availability of soil nitrogen is a function of residual soil N (or nitrogen present in the soil) and N mineralized (released by the organic pools in the soil) from previous crop residues.

However, environmental and management factors greatly influence cover crop decomposition dynamics, making it a challenge to consistently and accurately predict the amount of N that will become available, or when it will become available, to a subsequent crop. We compiled field studies from Nebraska and other corn-producing states that evaluated the range of biomass production of cover crops, the amount of N in their biomass, and their C:N ratio (Table 1). While these studies do not provide exact estimates of when N is available to subsequent crops, they can give us some information to help inform nutrient changes following cover crops.

Nitrogen Uptake by Legume Versus Grass Cover Crops

Cover crops acquire N through the uptake of nitrate and ammonium from the soil. When cover crops decompose, N is recycled back to the soil. Leguminous cover crops, owing to their symbiosis with rhizobia, can acquire N from the air (biological N fixation). When this N is released during decomposition, it is a net gain of N, so legumes are typically thought of as an N source or supplier. However, not all N in legume biomass is fixed N, as legume may take up considerable amounts of N from the soil (Redfearn, 2016).

The N in clover and vetch varieties commonly used in annual cropping systems can vary widely (Tonitto &Drinkwater, 2006). Among the studies included in Table 1, Nebraska hairy vetch biomass production was in the lower range with 364 to 724 lb/ac, which contained 12 to 29 lb N/ac. Red clover was more productive with 78 lb N/ac. In the Eastern United States, cover crops, especially hairy vetch, had more biomass and N, probably due to milder and wetter climates.

Winter cereals are commonly used in the Midwest as cover crops because of their winter hardiness and high early spring biomass production. They are also very effective in taking up mineral N and are ‘scavengers’ for nutrients that have moved to the lower part of the root zone, rescuing nutrients that may otherwise be lost (Berg told et al., 2017).In Nebraska, rye produced between1,312 and 2,072 lb/ac of biomass, which contained between 34 and 54 lb N/ac (Table 1).

When Does the Nitrogen From Cover Crop Residue Become
Available?

Cover crop N release should be synchronized with N demand of the succeeding crop. The N accumulated in the cover crop biomass will be available to crop absorption after mineralization, which depends on soil moisture and temperature, soil type, and the carbon to nitrogen ratio (C:N ratio) of the biomass(Gil and Fick, 2001). The C:N ratio is the amount of carbon in cover crop biomass divided by the amount of N. It is often used to predict how fast soil microbes will breakdown residue and release residue N back to the soil. Microbes use the carbon in residues for energy and the N for protein (think growth). A C:Nratio of 24:1 is considered “ideal” as it has the balance of carbon to N that soil microbes need. Residues with greater C: N ratios will decompose slower because there is not enough N for microbial growth. To decompose residue with high C:N ratios, microbes take up N from the soil, thus immobilizing or “tying up” N. Residues with C:N ratio slower than 24:1 decompose quickly, and because there is more N than microbes need, N will be available for the next crop (USDA, 2011).

Legumes residues typically have lower C:N ratio (Table 1) and decompose more rapidly than grasses, providing readily available N to the subsequent crop. However, if the subsequent crop cannot take up the N, there is potential for loss. Cereal rye residues often have high C:N ratios and may immobilize soil N. Because of that starter fertilizer is typically recommended to overcome immobilization, with a rate between 30–50 pounds of actual N per acre (Midwest Cover Crop Council, 2019).An experiment in 2015 in Carbondale, IL, assessed the time it took for N from a legume (in this case, hairy vetch) and grass cover crop (cereal rye) to be released. Hairy vetch rapidly decomposed and released about 70 lb N/ac within the first 4 weeks after corn planting (Fig. 1). Cereal rye residues released less than 10 lb N/ac during that same period, and overall released much less N (Sievers & Cook, 2018).Some strategies, such the incorporation of the residues, can result in faster N release. The use of mixes of grasses and legumes can also modify the C:N ratio and speed up decomposition.

The Bottom Line: Consider Your Species, Biomass, and
Environmental Conditions

Biomass production, N uptake, and C:N ratio vary widely across the United States, with Nebraska on the lower end of productivity. The N in cover crop biomass will be released within a few weeks after termination, however, decomposition varies with soil moisture, soil temperature and C:Nratios. Therefore, not all biomass N will be available for the subsequent crop. A better understanding of cover crop N release and cash crop N uptake can help to optimize crop synchrony and the choice of species to grow. Some cover crop species have the potential to produce a high amount of biomass, providing great soil protection and reduce nitrate leaching, but they may not be suitable as an N source for a subsequent crop. Mixing cover crop species can overcome shortfalls of individual species and should be explored in more detail.

On 8th November Hutchinsons is hosting its inaugural Agroecology conference, giving farmers the chance to discover how to make the most of regenerative farming practices to benefit the environment and the bottom line.

Agroecology: Making the Transition will address many of the core regenerative agriculture principles, which head of Agroecology, Ed Brown, believes form the basis of good agronomy in a rapidly changing industry. Rising costs, changes to farm support, and increasingly extreme weather events, have hastened the need to build more resilient production systems that harness natural processes and reduce the need for artificial inputs. “The days of ‘high input, high output at all costs’ agriculture are numbered. The focus is much more about taking an holistic approach to farming and agronomy.”Hutchinsons is helping farmers do this with the launch of its new Agroecology service, and November’s conference will be packed with practical advice about sustainable farming practices. “Whether you’re a farmer that has already moved to a more resilient farming model, or are just starting out, the conference should have something for everyone.”

Speakers include Knight Frank’s Tom Heathcote, who is passionate about regenerative farming, and has helped a number of businesses transition to more sustainable farming systems, making him ideally placed to offer advice on business structuring and finance. Soil health is widely recognised as a cornerstone of sustainable farming systems, so Hutchinsons’s Ian Robertson will explain the importance of understanding your soil before making any significant structural or operational changes. Internationally-renowned independent researcher and regen consultant, Joel Williams, will also be present to offer a technical insight into his latest research. Two farmer speakers, at different stages of their agroecology journeys, will be there too. Ben Taylor-Davies, aka “regen Ben”, will share his experiences from years of adopting regenerative practices on the farm at Ross-on-Wye, while Harry Heath, who hosts the Helix Agroecology farm, will explain how he has tackled soil health issues on the Shropshire pig and arable farm.

“For us, we’ve gone through that early phase where we recognised our soils weren’t in the best of health, with significant slumping and erosion, ”says Mr Heath. “We were massively over-cultivating, and with subsoiling in particular, we found the more we did, the more we had to do, to artificially create structure. “But we are now well down the implementation phase, having converted “to direct drilling five years ago. ”Cover and catch crops, grazed off by sheep or pigs, are integral to the rotation, improving natural structure through a diversity of root structures, while also feeding soil biology. “Soil health and microbiology are always at the forefront of our decision making process,” Mr Heath adds. “The symbiosis that exists between the microbiology and the plant is vital and making sure we maximise that is integral to agroecology.

“But the key is to be openminded. To get off the conventional treadmill, you have to think differently, recognise it’s not all about the crop and continually question everything you do.”