Bartholomews Cover Crop Trial
Drilled 03/09/2020
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Aims & Objectives The cover crop trial was established to show a selection of useful species and mixes that we offer, to highlight the benefits, note observations and extract informative data. This was done to field scale to allow for any disparities in conditions across the site. A selection of individual species and different types of mixes were used. From this it will be valuable to note nutrient use or immobilisation, species vigour and growth habit alone, and how they respond when grown with other species. Biomass above ground and rooting structure will also be looked at. Both single species and mixtures were used to observe how individual components behave alone and when together. Is there synergy or antagonism? The mixes used are also designed for different purposes, emphasizing the key benefits of growing these crops. Soil samples were taken across all plots, at the start of the trial, and were taken later on in the season too. This will be to establish the quality of the soil and empirical evidence if the crops have made an improvement . In addition to the standard observations, Polysulphate will be applied at 2 different rates across all plots, to determine any improvements in rooting and nutrient immobilisation. Nutrient uptake will be monitored across the species and mixes with responses to the Poly fertiliser recorded. Throughout the duration of the crop in the ground, visual assessments will be made. These images will be compared and were recorded. Rooting structure will also be noted, and how it has affected the soil structure around it. The recording of nutrient uptake and soil sampling before and after the crop are to gain empirical data from the crops. Although some crops may not look the best above or even below ground, it can be taking up far more nutrients than expected. Once this data is recorded, it can support decision making of future cover crops, and what the crop needs to achieve. Green area index will be recorded to establish which species/mix is producing the most biomass above the ground. This will be particularly prevalent when looking to destroy the cover, and what is the best, most efficient method for the following crop, ground conditions and retaining the nutrients held by the plants. Protocol • Site subsoiled to remove compaction and then established using standard farm equipment. • Full spectrum Solvita analysis across the site. • Initial recording of emergence. • Pictorial record of crop progression. • Visual inspection of rooting and biomass of all plots including Polysulphate treated areas. • Tissue analysis of the plots to determine nutrient contents. • Second round of Solvita tests to observe any differences. • Crop destruction. • Follow up OM matter assessments to observe any improvements. This trial was drilled on the 3rd September 2020.
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Varieties & Mixes used
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Background on the species and mixes used Plot 1 – Forage Rye A useful species that has the ability to lift and hold Nitrogen. Its wide sowing period makes it a flexible option, whilst its roots can hold the soil structure together. Plot 2 – Berseem Clover A rapidly growing species, that will fix nitrogen. Plot 3 – Crimson Clover An annual clover fixing nitrogen, that can be grown on poorer sites. Plot 4 – Radish type 1 A deep rooting radish, with the potential to reduce 90% of beet cyst nematodes. Plot 5 – Fodder Radish Another deep rooting species, that is quick to establish and improves soil structure. Plot 6 – Spring Vetch & Plot 7 – Winter Vetch Slightly slow to get growing and established, but once it’s growing it can fix N in a relatively short period of time. Plot 8 – Buckwheat A brilliantly fast growing annual crop, that will scavenge phosphate and reduce leaching. Not winter hardy, buckwheat will die back after a hard frost. Plot 9 – N Fixer The species in this mix have been chosen to maximise nitrogen fixation in their growing period. Plot 10 – Sprinter The use of black oats in this mix enable it to be an excellent weed suppressant and isn’t a host to root lesions or stubby root nematodes. Alongside with the vetch being able to fix nitrogen, this mix is a useful and popular option. Plot 11 – EcoCover The mustard element will be quick to establish and grow, while the rye fills in the bottom growth, aiming to supress weeds efficiently. Plot 12 – Green Reward Containing 7 different species, Limagrain’s mix has the ideal combination of rooting depths and biomass yields above ground, nitrogen fixation, weed suppression and fast establishment. Plot 13 – Soil improver With 4 species, this Limagrain mix still has the ability to cover the different rooting depths and will help retain moisture in the ground. Plot 14 – Commando mix Specifically designed by Limagrain as a biofumigant mix, as the species included have higher levels of isothiocyanates. These chemicals have the ability to supress soil borne pests, diseases, fungal pathogens and weeds. It can also help with compacted areas. Plot 15 – Red reviver Produce by Limagrain, it is designed as a mix to undersow cereal crops with, providing ground cover and an extra forage post-harvest.
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First comparison photos Photo 1 taken 23/9/2020, photo 2 & roots analysis taken 22/10/2020. Plot 1 – Forage Rye Significant top growth over the period, with the plant looking a more vibrant green. The rye has thin roots which are not too deep rooting but holding the topsoil together. Plot 2 – Berseem Clover Plants are more visible in rows, more cover over the ground. Still not covering the soil completely. Some root nodulation showing further down the root structure. The roots are relatively long compared to the top growth and seem to be able to spread out. Plot 3 – Crimson Clover Not as much growth as the Berseem Clover. More volunteers showing. Nodulation showing on roots, nearer the surface. Similar to the Berseem clover the rooting depth is longer, and more fibrous roots. Plot 4 – Radish type 1 Significant top growth, with minimal bare soil showing. Good rooting beneath surface. A big tap root, with the ability to break through compaction, with long thin roots coming off the main root too. Plot 5 – Fodder Radish Massive amounts of top growth, even beyond that of the Type 1 radish – more biomass above ground. A longer thinner root below ground, with the ability to penetrate through the soil further. Plot 6 – Spring Vetch Little growth, with little ground coverage. Plot 7 – Winter Vetch Similar to spring vetch, but slightly more ground coverage. A mass of fibrous roots, holding the soil and spreading out, as well as downwards. Plot 8 – Buckwheat A substantial amount of growth above ground, and minimal bare ground to be seen. Some rooting below, but predominantly into stem/leaf/flower production. The roots tend to be small and thin, with not much downward penetration. Plot 9 – N Fixer As seen previously, the two species have not produced huge amounts of above ground biomass. Slightly more ground coverage than as single species. Good fibrous roots, keeping the soil structure. Plot 10 – Sprinter Slightly disappointing with the lack of growth/biomass so far produced with this mix. The oats have come up with more vigour than the vetch but has still not given much ground coverage. A good combination of longer fibrous roots and surface roots. Plot 11 – EcoCover Significant growth from the mustard showing, with good ground coverage too. The rye has not come up as well but is still showing. Fibrous roots from the rye, and a bigger, longer root from the mustard, useful for the topsoil and deeper down too.
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Plot 12 – Green Reward Good growth above ground, with the different species offering differing levels of growth. Very little bare soil left. The roots are of varying types and depths to reflect the species within the mix. This optimises soil improvement, with the deep rooting abilities, and the fibrous roots to
hold the topsoil together. Plot 13 – Soil improver
Another mix which has flourished, with different growth heights. The mustard has done well providing a good canopy. Not quite as much ground coverage as the previous mix. A good combination of deep roots and some thinner fibrous roots, not quite as effective as the previous mix. Plot 14 – Commando Despite the good ground cover in photo 1, this has only improved in photo 2. The plants are taller and broader, providing increased cover. A mix designed for Biofumigation; the roots are not the best for holding the topsoil together but have some deep rooting ability. Plot 15 – Red Reviver The IRG has really come along in the month even though it is not providing as much cover as other mixes. Designed as an undersowing crop, it will get growing later on in the season, and wouldn’t be outcompeting the main crop. The clover has really held the topsoil together.
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November photo comparisons Photos taken 6th November & 24th November 2020. Plot 1 – Forage Rye No major differences in growth. Plot 2 – Berseem Clover Significant upright growth, covering more ground area. Plot 3 – Crimson Clover Growth can be seen between the two visits, but as the clover exhibits very prostrate growth, this has been harder to judge. Plot 4 – Radish type 1 No real differences in top growth, but the roots have developed quite deep. There was a visible line where the crop had responded well to the Poly fertiliser, with more leafy matter above ground. Plot 5 – Fodder Radish Some top growth, there are visual differences between the two radishes above and below ground. These bulbs are slightly larger if a little shallower. Plot 6 – Spring Vetch Some growth across the plot, but not significant Plot 7 – Winter Vetch The plants seemed to have bulked out a little more, offering a lot more ground cover. There was also a visual colour difference between the Spring and Winter vetch, with the winter being a more vibrant green. Plot 8 – Buckwheat Has been knocked back quite a lot by the recent cold spells – but no hard frosts as yet. The crop looks thinner and some plants are senescing. Plot 9 – N Fixer Growth has shown more ground coverage across the plot, with the vetch being the more There has been good growth across this plot, with the oats progressing nicely. They have also responded well to the Poly fertiliser. The vetch is still present at good levels and shown further growth. Plot 11 – EcoCover The mustard continues to flourish in this mix, slightly swamping the rye element. In the parts with the Poly fertiliser, there is very little rye to be seen. Plot 12 – Green Reward The mix is still looking great, with the wide range of species holding well. There is plenty of biomass above ground, although some leaves are showing signs of yellowing. dominant species. Plot 10 - Sprinter
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Plot 13 – Soil Improver Similar to the EcoCover mix, the mustard is starting to look like the dominant species. below the mustard, however, the other species are still there and staying green, and producing biomass. Plot 14 – Commando This mix is a lot lower growing in it habit, but still holds the soil well and there is some biomass there. Plot 15 – Red Reviver The IRG and clover in this mix have flourished, providing plenty of ground cover.
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January Photos Photos taken 21st January 2021. After a recent spell of cold, wet weather, with some hard frosts, the cover crop trial has held up well. Plot 1 – Forage Rye Looking a little waterlogged, but still holding the soil well. Some of the leaves are showing signs of disease. Plot 2 – Berseem Clover The clover is holding well, with the plants still mainly upright, now at ankle height. Not showing any signs of frost damage. Plot 3- Crimson Clover Plants are showing good ground cover, and with their fibrous roots holding well. Plot 4 – Discovery radish The radishes still have good above ground leafy growth, with some leaves starting to turn yellow. Plot 5 – Fodder Radish Compared to the Discovery radish, the Fodder radish has a lot more top growth, and less yellowing of the leaves. Plot 6 – Spring Vetch While the vetch still has good biomass, it is showing purpling to the leaves. The plants are a lot more prostrate. Plot 7 – Winter vetch Compared to the spring vetch, the winter vetch is a lot greener, brighter and upright. Plot 8 – Buckwheat The plants have now almost fully rotted, leaving just the stalks behind. Plot 9 – N Fixer The mix is flourishing, still looking green and with plenty of biomass. Plot 10 – Sprinter The oats are providing plenty of green cover, still looking very well. The vetch is still present in the mix, filling in the bottom of the cover. Plot 11 – EcoCover The mustard is the dominant aspect to the mix, with the rye a little thin underneath. The mix is still standing well. Plot 12 – Green Reward The mix is still looking great, with the wide range of species holding well. There is plenty of biomass above ground, although some leaves are showing signs of yellowing.
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Plot 13 – Soil Improver Similar to the EcoCover mix, the mustard is starting to look like the dominant species. Below the mustard, however, the other species are still there and staying green and producing biomass. Plot 14 – Commando This mix is a lot lower growing in it habit, but still holds the soil well and there is some biomass there. Plot 15 – Red Reviver The IRG and clover in this mix have flourished, providing plenty of ground cover.
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February Photos Photos taken 22nd February 2021. Plot 1 – Forage Rye The plot is still showing good ground coverage, some leaves showing sign of disease. There is still plenty of biomass above and below ground. Plot 2 – Berseem Clover The plants are looking green and vibrant, with plenty of cover shown. Plot 3 – Crimson Clover Showing some signs of being knocked by the recent cold weather, with some tinges of purpling on the leaves. Plot 4 – Discovery Radish Some yellowing to leaves on the plants, but generally holding up well. Plot 5 – Fodder Radish There are significantly less leaves than in previous visits , but the plants are still giving some biomass above ground. Plot 6 – Spring Vetch The plants have taken a considerable hit from the recent cold weather spell, and the plants have mostly died off. Plot 7 – Winter Vetch Similar to the Spring vetch, the plants have show to be affected by the cold weather, and not looking as bold as they have done previously. Plot 8 – Buckwheat What is left of the stalks of the Buckwheat have almost become completely broken down. Plot 9 – N Fixer The vetch has almost all been killed out, as seen in previous plot, with the berseem clover still standing strong. Plot 10 – Sprinter The black oats are still standing, with some leaves starting to senesce. The vetch has survived better with the canopy of the oats. Plenty of biomass above ground. Plot 11 – EcoCover The mustard has been reduced to stalks with the leaves gone from the recent frosts. The rye is still standing strong. Plot 12 – Green Reward The rye and the radish seem to be doing the best after the cold period, with some of the other species being knocked out. There is still plenty of biomass, and good rooting depths.
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Plot 13 – Soil Improver This mix still looks green, with plenty of cover. The mustard has been knocked back, but the rye and radishes are still flourishing. Plot 14 – Commando Showing some signs of being hit by the cold weather, some yellowing of the leaves and the plants not looking as bold as previously. Plot 15 – Red Reviver This mix is thriving, with the Italian Ryegrass and clover start growing more vigorously. Offering plenty of ground cover and holding the soil well.
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Comparison photos
Forage Rye
Forage Rye 23/09/2020
Forage Rye 22/10/2020
Forage Rye 24/11/2020
Forage Rye 06/11/2020
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Forage Rye 07/12/2020
Forage Rye 17/12/2020
Forage Rye 21/01/2021
Forage Rye 22/02/2021
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Berseem Clover
Berseem Clover 23/09/2020
Berseem Clover 22/10/2020
Berseem Clover 24/11/2020
Berseem Clover 06/11/2020
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Berseem Clover 07/12/2020
Berseem Clover 17/12/2020
Berseem Clover 21/01/2021
Berseem Clover 22/02/2021
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Crimson Clover
Crimson Clover 23/09/2020
Crimson Clover 22/10/2020
Crimson Clover 24/11/2020
Crimson Clover 06/11/2020
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Crimson Clover 07/12/2020
Crimson Clover 17/12/2020
Crimson Clover 21/01/2021
Crimson Clover 22/02/2021
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Discovery Radish
Discovery Radish 23/09/2020
Discovery Radish 22/10/2020
Discovery Radish 24/11/2020
Discovery Radish 06/11/2020
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Discovery Radish 07/12/2020
Discovery Radish 17/12/2020
Discovery Radish 21/01/2021
Discovery Radish 22/02/2021
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Fodder Radish
Fodder Radish 23/09/2020
Fodder Radish 22/10/2020
Fodder Radish 24/11/2020
Fodder Radish 06/11/2020
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Fodder Radish 07/12/2020
Fodder Radish 17/12/2020
Fodder Radish 21/01/2021
Fodder Radish 22/02/2021
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Spring Vetch
Spring Vetch 23/09/2020
Spring Vetch 22/10/2020
Spring Vetch 24/11/2020
Spring Vetch 06/11/2020
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Spring Vetch 07/12/2020
Spring Vetch 17/12/2020
Spring Vetch 21/01/2021
Spring Vetch 22/02/2021
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Winter Vetch
Winter Vetch 23/09/2020
Winter Vetch 22/10/2020
Winter Vetch 06/11/2020
Winter Vetch 24/11/2020
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Winter Vetch 07/12/2020
Winter Vetch 17/12/2020
Winter Vetch 21/01/2021
Winter Vetch 22/02/2021
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Buckwheat
Buckwheat 23/09/2020
Buckwheat 22/10/2020
Buckwheat 06/11/2020
Buckwheat 24/11/2020
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Buckwheat 07/12/2020
Buckwheat 17/12/2020
Buckwheat 21/01/2021
Buckwheat 22/02/2021
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Sprinter mix
Sprinter mix 23/09/2020
Sprinter mix 22/10/2020
Sprinter mix 06/11/2020
Sprinter mix 24/11/2020
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Sprinter mix 07/12/2020
Sprinter mix 17/12/2020
Sprinter mix 21/01/2021
Sprinter mix 22/02/2021
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EcoCover mix
EcoCover mix 23/09/2020
EcoCover mix 22/10/2020
EcoCover mix 06/11/2020
EcoCover mix 24/11/2020
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EcoCover mix 07/12/2020
EcoCover mix 17/12/2020
EcoCover mix 21/01/2021
EcoCover mix 22/02/2021
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Green Reward mix
Green Reward mix 23/09/2020
Green Reward 22/10/2020
Green Reward mix 06/11/2020
Green Reward 24/11/2020
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Green Reward 07/12/2020
Green Reward 17/12/2020
Green Reward 21/01/2021
Green Reward 22/02/2021
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Soil improver mix
Soil improver mix 23/09/2020
Soil improver mix 22/10/2020
Soil improver mix 06/11/2020
Soil improver mix 24/11/2020
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Soil improver mix 07/12/2020
Soil improver mix 17/12/2020
Soil improver mix 21/01/2021
Soil improver mix 22/02/2021
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Commando mix
Commando mix 23/09/2020
Commando mix 22/10/2020
Commando mix 06/11/2020
Commando mix 24/11/2020
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Commando mix 07/12/2020
Commando mix 17/12/2020
Commando mix 21/01/2021
Commando mix 22/02/2021
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Red Reviver mix
Red Reviver mix 23/09/2020
Red Reviver mix 22/10/2020
Red Reviver mix 06/11/2020
Red Reviver mix 24/11/2020
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Red Reviver 07/12/2020
Red Reviver mix 17/12/2020
Red Reviver mix 21/01/2021
Red Reviver mix 22/02/2021
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Roots differences 22/10//2020
L-R Plots 1-5 Forage Rye, Berseem Clover, Crimson Clover, Radish (type 1), Fodder Radish. Plot 6 was omitted.
L-R Plots 7 -10 Winter Vetch, Buckwheat, N Fixer (Red Vetch & Berseem Clover), Sprinter (Black oats & Vetch)
L – R Plots 11 -15 EcoCover, Green Reward, Soil Improver, Commando, Red Reviver.
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Roots differences 17/12/2020
L-R Plots 1-5 Forage Rye, Berseem Clover, Crimson Clover, Radish (type 1), Fodder Radish.
L-R Plots 6 -10 Spring Vetch, Winter Vetch, Buckwheat, N Fixer (Red Vetch & Berseem Clover), Sprinter (Black oats & Vetch)
L – R Plots 11 -15 EcoCover, Green Reward, Soil Improver, Commando, Red Reviver.
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Rooting Scores Analysis taken 22/10/2020 Roots are given a score from 1 – 10, depending on if they are fibrous (1) or deep tap roots (10). This will give analysis of how well the roots, and therefore the plant, holds the soil together to avoid run off.
From this, the individual species and mixes can be given a score on its ability to hold the soil together – 1 not holding the soil at all & 10 holding the soil together.
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Cost comparisons
Looking at the cost analysis of these mixtures, it is very much weighted on the sowing rates, not just on the cost per kg. For example, the Radish comes in at a relatively high per kg price, but at a low sowing rate of 10kg/ha, this becomes a cost effective crop. Comparably, Buckwheat is far cheaper per kg, but at a higher sowing rate of 70kg/ha, this can become more costly. Ultimately, it comes down the requirements, how it fits in with the rotation and the longevity desired of the cover.
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Green Area Index Using green area index will give an idea as to how well covered the ground is as the crop is growing. It will measure the ratio of green leaf area to the ground area, giving a score to be able to compare how different species or mixes cover the ground. This can then be linked to rooting type and depth to be able to see the most effective and efficient cover crop species or mix is.
From this graph, and as well as visual analysis in the field, the Radish is providing the most ground cover. This is due to the large amount of biomass from the green leaves and the height that the plant has reached. Similarly, the mixes that contain Mustard have also provided good amounts of cover. Species such as the vetches and the clovers have lower scores on the GAI, as they are smaller and less bulky plants. This, however, it not necessarily a negative when choosing as a cover crop, as there is less biomass to destroy and then incorporate.
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Polysulphate Biomass comparisons PolySulphate fertiliser from ICL contains 4 key nutrients: Sulphur, Potassium, Magnesium & Calcium. When applied, these nutrients are readily available to the plant.
Across the trial an application of Polysulphate was made, 1 tramline width wide. From this we have been able to compare biomass difference between the treated and untreated plots. From a quadrat within the plot, all plants (above and below ground) were weighed to produce a biomass weight. The chart above illustrates the findings. We can see from the graph, that the individual species have responded the with the largest increases in biomass, compare to the mixes. Within the mixes, we notices that the dominant brassica species had the best response, which promoted their growth and therefore lead to them smothering out the smaller/lower growing species. At the same time as measuring the biomass, the tissue and root samples have been sent off for analysis, looking at nutrient uptake and carbon sequestration.
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Tissue sample analysis
From samples taken on the 10th November, ICL have put together the nutrient uptake of the species and mixes that were taken from both untreated and treated parts of the plots. This has shown how the different species have responded to the Poly fertiliser. A point to note with the Soil improver – this mix seems to have responded negatively to the Poly, which could be due to the mustard taking over in the mix, and other species being drowned out.
There has generally been a good response to the Poly with Nitrogen uptake.
A mixed result with the Phosphorus, as expected the Buckwheat (Kora) has taken up a significant amount. The N fixer has got a very low amount, and not much of an increase in the treated section. This is also reflected in the Nacre winter vetch’s response.
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The individual species seem to have had the best response and uptake of Potassium, which is not reflected in the mixes.
Again, Carbon uptake has been more varied, and a better response seen in the indivudal species.
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There has generally been a negative repose to the Manganese uptake, with Buckwheat and N fixer, being the exception.
Sulphur uptake has seen an increase across the majority of individual species, while the mixes have the negative response. The Winter Vetch (Nacre) has the only negative response as an individual species, whereas the N Fixer mix, has the only positive uptake from the mixes.
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Calcium again has seen the positive uptake across the straight varieties, rather than the mixes. N fixer is the only exception to this.
Both the Discovery Radish and the Buckwheat have had the best uptake of Boron with the Poly, but the Buckwheat has the bigger difference from untreated to treated. The mixes have still got the negative uptake in comparison.
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Iron uptake has generally seen a negative effect from the Poly fertiliser, but this is only slight compared to the untreated results. The Buckwheat has seen almost 50% increase in uptake, while the N Fixer has seen only a small increase in uptake.
Buckwheat has again seen the biggest increase in uptake of Copper. Whilst the single species have very little difference and mixes have seen a slightly negative uptake. The Soil improver has the most significant decrease in uptake from the Poly.
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The Zinc uptake has been good across the single species and the mixes, just with mixes seeing that slightly negative effect.
Magnesium uptake has been low but consistent, apart from the Buckwheat. This uptake has signifi- cantly improved.
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Molybdenum uptake has been varied across both the straights and mixes. The Vetch and Buckwheat have the only positive uptake from the Poly treatment.
Key Points: Buckwheat has seen the best uptake across all elements with the Poly treatment. This has been around an 50% increase of uptake. Generally, uptake has been better from the single species with the Poly treatment, while the mixes have seen a negative effect. Untreated, the mixes have the better uptake. This could be down to the increased growth of certain elements in the mix, smothering out other important elements. This has particularly been seen with the Soil improver mix, and the Mustard taking over. This has meant that in the treated section, Mustard has been the only viable species, and has not seen the benefits of the uptake from other species in the mix.
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Notes
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Notes
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Notes
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Speak to one of our qualified advisors today Tel: 01243 755620 Email: info@bartholomews.co.uk Visit our website at www.bartholomews.co.uk Follow us @bartsagri
BerwickStLeonard Salisbury 01243755665 fisherton@bartholomews.co.uk
ChichesterFoodPark Merston 01243784171 agri@bartholomews.co.uk
GoldenCross Nr.Hailsham 01825872697 goldencross@bartholomews.co.uk
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