Farmyard manure and cover crops for soil improvement

The group have skipped a year of treatments due to changing contractors, though there are still cover crops in the ground.  As this is a long term trial examining soil metrics this will not impact on the overall results. However, the trials will continue next year and the results will be analysed and a final report completed by the end of 2024.

The trial field of Spring Oats is being harvested at the moment - weather permitting. When the straw has been baled the farmyard manure will be spread on the trial site and a cover crop will be sown. The manure is tested before application so that application rates can be calculated accordingly. A late harvest means that the cover crops are being sown later than is ideal, the farmer has elected to sow mustard as it a lower risk and as the following crop is wheat only a short term cover crop is needed. It will be spread on the surface and rolled in to give it the best chance of establishment.

After the 2018 harvest, manure was applied according to the trial plan, on two quarters of the field at two different rates. As noted previously, cover crops were unable to establish in the drought conditions of 2018 and so were postponed until the 2019 season.

The planned Oilseed rape crop failed after drilling due to drought conditions and pest problems with Cabbage Stem Flea Beetle. The crop was re-drilled with Spring Oats and has been managed to the normal farm standards and will be harvested when ripe. A decision on cover crops will be made after the 2019 harvest and will be dependent on rain and potential weather conditions.

Analysis of the farmyard manure will be taken to assess the impact on fertiliser rates for the following wheat crop, and the specifics of the next FYM application will be made based on those results.

The triallists are planning to combine the current barley cash crop in mid-July, clear all the straw and drill again with oil seed rape by mid-August. All muck will be spread on the 2 quarters of the field at two rates, weighed on via their weighbridge. The spreader is able to spread finely, and the triallists will direct drill through that with either a Horsch or JD direct drill.

Unfortunately with the very dry weather conditions this year, it is difficult to drill anything and the cover crops in the trial will be postponed until next year. Despite this, the applications of FYM and control to compare this to will go ahead.

The researchers are due to take muck samples for analysis in early August. As the ground is currently too dry, the VESS tests are not feasible, and so this will be delayed until there is enough moisture in the soil to do so.

Following a farm walk earlier this year, a suitable, level field has been identified for trialling on. This field is due to be oil seed rape (OSR) in the first year of the trial, with a wheat crop following this.

The field will be split into 4 management areas, each approx. 2ha, so that the following 4 treatments can be implemented after harvest 2018 before the establishment of the 2019 crop:

• Control (i.e. current practice)
• Organic manure (cattle FYM) applied at 250 kg/ha total N
• Cover crop
• Cover crop + organic manure applied at 250 kg/ha total N

The treatments will be included in the farm rotation with cover crop selection depending on the next crop in the rotation. i.e. cover crops will be included before winter cereals and spring crops and not before the establishment of winter oilseed rape. The treatments will be in place for 5 harvest seasons initially.

The use of tramline sized test plots for yield analysis, with smaller replicated analysis taken within each tramline will be used to provide a good mix of farm scale and scientifically robust results. The use of tramline trials allows the trial to be run as part of the farm system, with readily available machinery, and therefore does not require specialist equipment.

Cover crop options were discussed and the view was that a least cost policy should be taken. Oats, forage rye, vetches, mustard and buckwheat are all possible, the only requirement being rapid biomass production in the timescale available, particularly in the window between rape harvest and wheat drilling. The triallists will choose the specific varieties to grow later in the trial, which gives them time to consider the pros and cons of each and allow the weather conditions to inform their choices. This will be discussed before being chosen later in the year.

ADAS will be carrying out the sampling and funding the analysis. A suite of measurements will be undertaken at the start of the project and periodically during the rotation to establish the impact of the contrasting management techniques on soil chemical, physical and biological properties. These will include:

• NRM Soil health suite (Soil pH, extractable P, K, and Mg; soil vita and organic matter) - Year 1, 3 and 5 (3 replicate samples from both FYM and cover crop treatments)
• Visual assessment of soil structure – annually 2018 – 2022 (3 replicate measurements from both FYM and cover crop treatments)
• Soil microbial biomass carried out using the standard fumigation method– Year 1 and Year 5
• Yield measurements will be taken from each treatment each harvest year using information from the farm yield map and data processed using the ADAS Agronomics methods
• An assessment of costs (e.g. manure spreading, cover crop seed, additional cultivations and agronomic inputs) and benefits (e.g. savings in fertiliser inputs, soil structural improvements) associated with the different management options will be carried out annually and over the rotation.

The triallists have drilled their initial cash crop of the year, which will be harvested next summer. After the harvest, the triallists will look to be adding FYM and potentially drilling cover crops to trial soil improvement on.

The estate managers, researcher and coordinator met to discuss the requirements of the estate, look at the site and allow a trial protocol to be developed. The field lab is to include a number of tenant farmers on the estate who will be consulted at the next meeting.

The soil is fairly heavy with rotational ploughing the normal practice, blackgrass is a weed problem and this has driven the development of a 3-year rotation on the lighter land and a 5-year rotation on the heavier land. The rotation is wheat, spring Barley, and Winter oilseed rape. A fallow year is part of the 5-year rotation.

A straw for muck deal with one of the estate tenants gives a source on FYM. The Estate is in an NVZ and so this would need to be accounted for in nitrogen planning and trial design.

There is a large flock of sheep and so cover crops are currently part of the farming system, but not deliberately as a soil improver. The greening requirement of BPS could also be a consideration of the trial outcomes.

Green Waste compost is not produced locally and the cost of importing sufficient quantity onto the estate makes it an unattractive proposition. The Proposed trial is therefore to look at the use of FYM and cover crops as a method of increasing soil organic matter and soil structure. Initially baseline test of the soil will be undertaken and a trial protocol put in place to try both methods of SOM improvement within the existing rotation. The intention is to start the trial post-harvest 2018. An option to include a one year clover crop within the rotation could also be considered.

The use of tramline sized test plots for yield analysis, with smaller replicated analysis taken within each tramline would likely provide a good mix of farm scale and scientifically robust results.

After a farm walk a suitable level field has been identified. This field is due to be OSR in the first year of the trial. Cover crop options were discussed and the view was that a least cost policy should be taken. Oats, forage rye, vetches, mustard and buckwheat are all possible, the only requirement being rapid biomass production in the timescale available, particularly in the window between rape harvest and wheat drilling.

A second field which is heavy and has a poor structure is due to be grassed out to a ryegrass clover ley and could be used to measure potential soil improvements on the estate by using grass leys as part of the arable rotation.