Due to poor weather conditions in early spring this year the triallists have been unable to do rock phosphate (P) applications. This means that unfortunately they we won't be able to get any useful comparisons of leaf P status this year. Despite this, they are planning to apply P late, and harvest the plots so that a P balance exercise can be carried out. They then plan to continue the trial next year with and hope to have gathered useful soil data then.
The group are planning to meet within the next couple of months to discuss progress and next steps.
Milestone: Progress update
Field lab open to new members
This field lab is welcoming the addition of new members who are interested in trialling, please contact us to find out more. There will be a meeting in February for which new members are welcome to join to hear more on the trial and the group of farmers already involved.
Milestone: Looking for new triallists
2017 results meeting
John Hammond presented results and analysis to date on the P-FYM trial for 2017 season (please download the PDF presentation in 'Field Lab Documents' for the data).
Three cereal fields were plot harvested in July 2017, two of which showed “almost” significant increases in yield and grain P concentration where GAFSA was co-composted with manure, vs applied separately. (The third field showed almost no yield advantage but was only composted for minimal time, unlike those with measurable response).
Two grass fields were sampled in June 2017, before the 2nd cut, and showed a significant increase in tissue P concentration for treated vs untreated fields.
Soil analysis for phosphate, post-harvest, was carried out on four fields, however results need further analysis once all the yield data is gathered. One anomaly identified as possibly due to variation in GAFSA application timing.
After brief discussion, it was agreed that there was sufficient response to warrant continuation of the trial for 2018 and 2019 harvest. Any additional land which could be added to the trial in spring 2018, and 2019, would be valuable, to increase replicates. The greater responses had all come from co-composting for 4 months minimum.
There was a general discussion on other aspects of crop phosphate nutrition, especially on soil type, “placement” of FYM in seedbed, composting AD solid, green waste compost, biosolids production methods and “crystal green” as a product. It was noted that fungal activity in compost heaps is more effective at making P available, however bacterial activity tends to circulate larger amounts of inorganic P but it remains less available to plants.
Milestone: 1st soil biological and structural assessment
Further idea discussions - tilling
There was a brief discussion of the idea of a “tillage trial”. The majority present do not believe that minimal tillage in an organic scenario is feasible on a regular basis, mainly due to the problem of grass weeds in a mixed rotation, and also due to need to remove wheelings from straw collection and FYM application operations. Strategies for identifying and minimising compaction would be useful.
Milestone: 1st trial harvest measured and soil assessment
Field lab meeting with guest talk
The group met at one of the host farms to have an update on the field lab trial. Adrian described the field lab aims of co-composting rock phosphate with farm yard manure and applying it to 5 plots over 3 farms. There is a range of soil types and crops/stages in the trial. The plots will be compared with a control treated with FYM then rock phosphate separately. Rates are at commercial and realistic levels, not more extreme research intensities. Treatment will be 'little and often' and followed with soil health monitoring.
The group had discussions on compaction control and the pros and cons of disrupting the soil profile. There were interesting discussions about how much effort/cost is reasonable when trying to improve soil biology in fairly unresponsive soil types such as heavy clay. It was generally agreed that any efforts to improve soil organic matter and structure will be of benefit however.
Dr Jackie Stroud from Rothamsted gave a guest talk on earthworms, their behaviour and ecology (key points in following post). The group went to one of the trial sites to look for earthworms and were shown the OPAL guide (see www.opalexplorenature.org/soilsurvey for more information). The weather has been very dry and made worm hunting difficult in the tight dry soil, but some top burrowing red worms were spotted (photos in the Activity Feed). The OPAL earthworm ID guide is in Field Lab Documents.
Milestone: Update meeting
Earthworm ecology: key points
Dr Jackie Stroud gave an interesting talk at the group meeting about earthworm behaviour and biology.
- Ploughing can reduce the population in a field by 20%.
- There are top- and deep-burrowing species. The deep burrowing species have permanent burrows channelling 6m down the soil profile. They leave 'middens' (a small pile of collected vegetation) on the surface at the entrance to their burrow and pull vegetation down the column.
- Deep burrowing earthworms mate 2 or 3 times a year producing ~20 cocoons. They mate at night as they are very light sensitive, particularly after a very heavy rainfall.
- Cocoons are viable deep in the soil for up to 2 years and populations can recover in 3 years.
- There is a correlation with increases in SOM and middens counts. Legume undersowing has been strongly linked to good worm populations. The worms prefer the fresh litter and dung can act as an attractant
- Populations are patchy in a field and can make surveying for overall abundance problematic. Middens are a useful indicator of activity and can be easily surveyed year round as the top burrowers tend to be present if the deep burrowing species are.
- There is little work ongoing as the effect of sprays and slug pellets on earthworm populations.
Milestone: Update meeting
Update on field lab trial
P-FYM trial progress to date
4 of the trial plots have been spread with co-composted FYM and GAFSA (reactive rock phosphate) in the autumn, 3 have been drilled with winter wheat and one remains in grass/forage cropping.
A further 2-3 plots of grass will be spread with FYM/GAFSA in the spring, to be ploughed out in autumn 2017.
The C-FYM trial may go forward at some stage depending on sites offered and funding, but this looks unlikely before autumn 2017.
Milestone: Year 1 trial established Autumn to Spring
Meeting November 2016 - trial progress
The progress of the P-FYM trial was discussed (see next achievement post)
The group discussed that the start of these trials offers an opportunity to re-evaluate our methods for assessing biological activity and soil structure. There was a discussion about methods used to date, especially “CO2 burst”:
- Adrian Hares has been in correspondence with a similar research project involving SAC soil researchers, which have used bait lamina sticks to assess biological activity.
- John Hammond described a “citizen science” project , funded by RHS , which is the work of a PhD student at RU. This involves using the weight loss of teabags , buried for 2-3 months , to gauge biological (bacterial & fungal) activity. The group was interested in this, both for our trials and as a simple on farm test to be used by group members for their own purposes/comparisons. JH to obtain further information on protocols, AH to discuss a basic soil percolation test with a soil scientist. There may be opportunities for postgraduate student involvement at some stage in the future .
Andrew Woof described his new organic conservation tillage system and progress to date, and the machinery involved. There was a long discussion around the advantages and pitfalls of direct drilling; cover crop establishment, management and nutrition; pests & weeds. The other farmers present shared their experiences in a “conventional” context . There was a discussion on promoting mycorrhizal activity by rotation, alley cropping and grass margins.
There was a visit to 2 fields which were part of the plot assessment in spring 2016; Giles Hill (organic oats) and Airfield West (conventional cover crop).
The next meeting is planned for January 2017.
Milestone: Progress meeting
Rock phosphate and manure field lab plan (P-FYM)
The objective is to compost rock phosphate with on farm manures, and apply to combinable crops/new leys, to test the theory that P in rock phosphate is made more available, than with direct application to soil.
Full details are available in the field lab documents. The trial method being proposed is summarised.
Rotation and rates
- Co-composted FYM and screened Gafsa (reactive rock phosphate) to be applied to first cereals/grass reseeds established in Autumn after ploughing leys, to raise P availability and bacterial/fungal activity.
- Control - same rate FYM and rock phosphate in sequence, with matched timing on farm.
- Application into ploughed land in early autumn, where conditions permit. If this is not possible then top dress in spring in seedbed or once tramlines are visible.
- If 2nd cereals is a spring crop the sow winter cover and apply to cover is possible, otherwise top dress spring crop. If winter crop then plough as 1st cereal.
- There is no application before 3rd cereal allowing soil sampling at the end of the field lab to be more accurate by reducing the amount of applied (unavailable) P in samples.
- Manure rates vary and will be compared in-farm for available N. P is added to give enough for crop offtake and build indices as per RB209, assuming 50% availability in the first year.
- rates adjusted to ensure that C:P ratio of additions does not increase over 200 (as this reduced P immobilisation)
- Measure soil biology annually in spring: microscopy, CO2 burst, worm count.
- Resin P (both profiles), PKMg, OM and physics at the end of the field lab.
- Yield assessments by combine/quadrat/remote sensing according to farm facilities
- Records of labour, machinery use, input costs, for cost/benefit analysis
- Plant tissue P annually (if funding obtained)
- Measure specific mycorrhiza counts (if funding obtained)
Milestone: Develop field lab (and funding) proposal
Optimised C:N soil amendments trial proposal (C-FYM)
The objective is to compost on farm manures and high C:N products, and apply to combinable crops/new leys. This is to test the theory that there is an optimum C:N ratio of applied products which promotes fungal populations in soil and enhanced soil organic matter (SOM). This ratio being approximately 22:1.
The full details of the field lab idea is in the field lab documents. A summary is given here.
Rotation and rates:
- Optimised manures to be applied to 1st cereals/grass reseeds, which are established in autumn after ploughing leys as per the P-FYM trial. The principle is to make substrate available to fungal populations in the topsoil soon after being perturbed with inversion.
- Control - rate of FYM which applies the same amount of available N and P; if K is limiting then using Sylvinite may be an option. Matched timing of optimised FYM and FYM on farm.
- Applications on to the ploughed areas in early autumn where conditions permit. Otherwise top dress in spring in seedbed or once tramlines are visible.
- If 2nd cereal is spring crop then sow winter cover and apply to cover if possible otherwise top dress; if winter crop then plough as 1st cereal.It is imperative to sow on winter cover where before beans and in an NVZ. Repeat for any 3rd cereal/grass reseeds.
- As with the P-FYM trial the manures ratges are per farm and set to give comparable rates of available N. The amount of inverted green biomass to be measured (grass leys and cover crops) and available N allowed for in FYM rate calculation - approximately 50kg available N in year 1 has been proposed but will be assessed further.
- the composting regime to be standardised as far as proacitcal ie where high C:N ration compost is added, target temperature range, DM. Also, ensuring that C:P ratio of additions do not exceed 200 as this reduced P immobilisation.
- Measurements to be taken are the same proposed for the P-FYM field lab method.
Milestone: Develop field lab (and funding) proposal
Shortlisting trial options
The group met to further consider the proposed shortlist of trial options drawn up at the June meeting, after considering the results of the trial site evaluation in the spring. These options centred around measures to boost soil organic matter, biological activity and phosphate availability. The current on farm practices across the group were reviewed, in terms of the timing of manure and compost applications, types, crops and inversion.
Bearing in mind the wide range of farming types, a decision was made, in principle, to conduct two separate trials over 3 years across the 18 or so sites, to:
- examine the effectiveness or otherwise of co-composting FYM and rock phosphate fertiliser, before application to cereal, cover crops, pulse or grass seedbeds. This to be compared to normal on farm manure application and separate phosphate. Effect to be measured on yield, soil biology, and soil P indices.
- alter the C:N ratio of on farm manures to encourage soil fungal activity, again applying to cereals, cover crop, pulse or grass seedbeds. Effect on yield, soil biology and SOM to be measured .
These options will have a final decision to be made based on funding availability, and sufficient trial plots being available to ensure results are valid statistically. The next step is to plan the trials and determine funding required.
Milestone: Meeting to discuss options for Autumn trials
Soil results meeting
John Hammond presented the statistical analyses of the plot survey carried out in April 2016.
The results are detailed in full in the field lab documents.
In summary, there were correlations between various soil parameters:
- the CO2 burst test was positively correlated with soil moisture, active bacteria, total fungi, potassium, magnesium and soil OM.
- The above were positively correlated with VESS score i.e. worse topsoil structure.
This may be explained by the fact that most of the plots were grassland of various ages, the older leys having accumulated more SOM and soil biological activity, but also more compaction since establishment.
Resin P (0-15cm) was positively correlated with active fungi and worm counts: we would expect that a biologically active soil would enable a greater soil phosphate availability, however the existence of a correlation does not prove cause and effect.
A relationship between soil type (RB209 category) and CO2 burst was noted, this may be due to the effect of drainage.
The group reviewed the questions that were raised at the start of the project, in the light of the findings and of other field labs already running. A shortlist of topics will be considered at the next meeting, centred around the question of boosting soil phosphate availability and soil organic matter with the use of bulky manures and cover crops. Trials will then be designed to commence in autumn 2016 on some of the sites surveyed.
Milestone: Results reported to group
Soil sampling methodology
11 fields were surveyed for a range of physical characteristics (including soil texture, depth, stone content, and pH) and any significantly different areas were separated out. This was done by in field assessment. Structural quality was scored using the VESS system developed by SAC.
In total, 23 soil 'zones' were created, and coded according to the Intelligent Precision farming (IPF) protocol. This was to enable:
- areas of similar soil type to be compared
- variability within the trial plots to be reduced
Within these zones, samples were gathered (using standard “W” pattern collection then split), and analysis carried out for a range of chemical and biological parameters. Worm counts were carried out, in 1 cubic feet at 5 points within the zone. The samples were collected over 6 days throughout April, the wettest fields last to enable some drainage. This enables:
- An assessment of “soil health” to be made
- Potential correlations to be found between, for example, physical condition and soil biology
- Changes in soil health to be tracked from year to year as the trials progress
- Examine any links between soil health and crop yield/quality in different areas of the field.
The soils were tested for Olsen P, Resin P (both in 0-15cm and 16-30cm horizons), K, Mg, Organic Matter (Walkley Black), Solvita /”CO2 burst”, active and total bacteria and fungi.
An attempt was made to measure bulk density with a 40mm diameter gouge auger, however it was difficult to penetrate compacted horizons and the results did not correlate with the other measures of compaction (VESS).
Milestone: Start soil sampling
Second meeting - method design with the researcher
The method for surveying trial plots and sampling, was reviewed and the costs per trial plot summarised. Some novel and low tech approaches to soil assessment were discussed. It is planned to have more information at the next meeting.
There was a short presentation by James Windridge from IPF on the opportunities for satellite mapping and the use of precision farming techniques to improve the running of on farm trials.
The group discussed who would be willing to host trials on their farms, and the balance between the researcher leading, and farmer involvement. There was also discussion around the opportunities for collaboration with other projects and field labs.
The next stage (trials from autumn 2016 onwards) was considered, and the benefits and risks associated with reduced tillage was discussed. The group felt that a form of reduced tillage trial would be of interest, but not to make any firm decisions until the results of soil testing in April 2016 were known.
The group went to a field at Eastbrook and examined the soil structure in various places in a long term ley, using the Visual Evaluation of Soil Structure classification method developed by Dr Bruce Ball (SRUC) - see online here for further information on the method: http://www.sruc.ac.uk/info/120625/visual_evaluation_of_soil_structure
Milestone: Meet researcher and define field lab
First group meeting
This was the first meeting of the group to identify what research interests and topics were shared amongst the members.
The group is a wide cross section of farmers, mainly mixed, organic and conventional. It was identified that most had questions about:
- how to measure soil biological activity
- how to reconcile reduced tillage and weed control
- and the best ways to integrate legumes, cover crops & composts into their rotations
After discussions, our provisional plans (subject to input from a researcher) are:
- set a base line on our own farms by identifying typical productive and less productive areas (field or zones within fields). Some if not all these to be “host” farms for further trials from autumn 2016 onwards. Pool our own knowledge and obtain any necessary training on “in field” assessment.
- drawing on work done elsewhere by the UK Soil Analysis group, use a range of soil biology tests to assess these areas in Spring 2016, and on a regular basis throughout the rotation. We will also comment on effectiveness & economic value of these tests.
- the results of the compost tea trials in Dorset on chalk soils in 2015 were noted, with interest and may feature in future trial design.
- design trials to be implemented from autumn 2016, probable treatments to include tillage depth, legume management and composts.
The long term objective being to develop a range of strategies to increase soil biological activity and nutrient availability which are appropriate to our own farming systems.
Milestone: First group meeting