With 2015 being the International Year of Soils it seems quite appropriate to be starting a new project to improve the condition of the soils at Hope Farm and monitor the soil biodiversity.
It is stating the obvious that soils are absolutely key to growing good crops. Well managed soils will drain better, provide better rooting potential for crops and have a range of wildlife that can actually benefit and promote crop growth. Poorly managed soils can lead to surface flooding issues and poor crop health, for example, and once soils begin the slide to poor condition it seems like a never ending cyclel.
Hope farm which has been in near continuous arable rotation for over thirty years. One of the greatest challenges is maintaining and improving the organic matter content in the soil. It has been many decades since Hope Farm was a classic mixed farm and sizeable quantities of farmyard manure were available to apply to fields to maintain and improve the organic matter content. Like the majority of other farms that converted to almost wholly arable enterprises the cropping system here increasingly relied on artificial fertilizers and evolving cultivation technology and equipment. For many it seemed the importance of the soil was somehow forgotten.
Wheat field with skylark plots at Hope Farm. Copyright Andy Hay/RSPB
Of course not everyone was so dazzled by the inputs and machinery that was available. There have been champions of soil fertility and condition, and in recent years their combined voices have become louder and greater numbers of farmers have begun to listen. This has partly been in response to a realisation that soils may be deteriorating, that inputs were becoming increasingly expensive and that pernicious weed issues were becoming more difficult to manage and part of the reason for that may be down to soil condition. Perhaps the most pressing issue is the ability of water to drain away freely especially on heavy land. Initiatives such as Catchment Sensitive Farming have helped to raise awareness of the issues of surface run off and erosion, and how much soil farms may actually be losing. Cross compliance (the rules we all have to follow to receive CAP payments) should in theory require a basic level of good practice in soil management, but in reality the rules are too weak and not well enforced enough to drive real change.
When we bought Hope Farm we inherited a purely autumn sown crop system comprising 1st and 2nd wheats, and oilseed rape. The industry wisdom at that time was this was the most appropriate cropping system for heavy land, heavily supported by a range of agri-chemicals and inputs. Nothing is constant in farming though. Fast forward 15 years and for harvest 2016 we will have a rotation including winter wheat, oilseed rape, spring barley, linseed, field beans and millet. Quite diverse for a 180ha farm.
This diversity opens up opportunities for improved management of the soil. With insufficient quantities of farmyard muck being available, and the significant cost of transporting here from areas which do have a ready supply, we looked for other options.
Green compost was one. This is created from the food and garden waste that many Local Authorities from households and businesses. Gardeners can collect the processed compost for free from local council depots, but for a farm like Hope Farm we need thousands of tonnes to make any meaningful difference. Such quantities come at a cost as well as the cost of transport. It may take several years to begin to see the difference in soil quality and crop health, and it is that time frame that often is difficult to adapt into the planning for many farms because of budgetary pressures and the tendency to focus on the short-term rather then the long-term.
The compost heap at Hope Farm. Copyright Ian Dillon/RSPB
Close up of the compost showing how rich it is in organic matter. Copyright Ian Dillon/RSPB
Another option is cover crops. These are crop mixes sown immediately after harvest and left in the ground until the following spring, thereby protecting soils over-winter from erosion, preventing nutrients from leaching into watercourses and improving the soil structure. The alternative for many is leaving fields bare which anecdotal evidence suggests exacerbates the deterioration of soil condition. While I had heard of cover crops I didn’t really know much about them until Nuffield Scholar, Tom Bradshaw, gave a talk to our local NFU Branch and then to a group of RSPB staff on the subject. Quite honestly, it was like the proverbial penny dropping. That sought after light bulb moment.
The shift away from autumn sown crops to spring sown crops on over a third of the farm provided the opportunity to put these options into practice. In the last few weeks we have had 1600 tonnes of green compost delivered and three different cover crop mixes ordered from Oakbank: black oats and vetch, forage rye and vetch, and forage rye, vetch and daikon raddish.
This week, immediately after oilseed rape harvest, we began the process of applying the compost and sowing the cover crops. Alongside this we have started a monitoring programme which will focus on the biota within the soil. Researchers from our Conservation Science department have developed a robust monitoring plan with a replicated trial of four plot types in three fields. Plot A has no intervention at all; plot B has green compost applied; plot C has a cover crop drilled the day after harvest; and plot D has both compost and green cover sown.
An example of the split plot design for monitoring soil condition and biota at Hope Farm.
Biodiversity is being monitored through collecting soil cores and vortis samples, and setting pitfall traps periodically over the coming years in these fields. This will enable us to monitor the changes in biota, soil condition and crop performance between the four treatments.
A soil core being collected at Hope Farm. Copyright Derek Gruar/RSPB
The normal monitoring of birds, butterflies, bees and moths will continue but it is very exciting to open a new era of monitoring, one that may help benefit biodiversity within the soil that most of us never see, but that may also help produce better, healthier crops for us all to enjoy.