SWARM Hub

Diverse Forages Project

Developing more environmentally resilient forage mixtures for ruminants

Which forage mixture would be most profitable in your farm environment with your management? The choice of grasses, legumes and herbs is diverse, and the simple ryegrass and white clover mixture may not be the best option in a changing climate with the additional pressures on the cost of fertility inputs. A new project is addressing these challenges.

Maintaining adequate forage productivity throughout the season is difficult and a greater resilience of biomass supply would be desirable for most farmers particularly in very wet or very dry conditions.

The choice of species in a mixture needs to take into account your soil type, drainage and pH, further consideration needs to include rainfall and the need for fertilisation. The correct management of mixtures is essential to maintain the desirable diversity of productive species - how low to graze, and how frequently, and with which livestock?

The choice of species available for forage mixtures, such as with Cotswolds Seeds Ltd, is in fact large with some of the more diverse mixtures containing up to 30 species many of which are under-utilised.

A new research project led by the University of Reading with Duchy College, North Wyke and Cotswolds Seeds as partners is focusing on developing biodiverse forage mixtures. We will be developing mixtures with functional diversity to improve biomass supply throughout the season, across a range of soil and climatic conditions, reducing mineral nitrogen inputs and nitrogen leaching and improving the economics of forage supply for livestock grazing and conservation.

Mixtures will be trialled across a minimum of 10 mixed farms from East to West, with a further detailed set of trials assessing agronomic performance and forage utilization for growth of cattle fed both grazed and conserved forage. The performance of the mixtures will be further assessed under extreme drought and water logged conditions at select experimental sites to simulate potential future productivity in a changing climate.

The first workshop for this project took place on the 19th January 2016 at Duchy College Stoke Climsland, where the component species in the mixture, management limitations and participatory farm sites were identified. If you are interested in this project and wish to received further information please contact Hannah Jones (h.e.jones@reading.ac.uk) or Chris Reynolds (c.k.reynolds@reading)

The project is funded by the Sustainable Agriculture Research and Innovation Club (SARIC) of the BBSRC.    

 

Soil Identification

Identification of soil group
Identification of soil texture

What is compaction?

  • Soil scientists describe good soil structure as having 50% of the soil volume occupied by particles of soil and organic matter, 25% by water, and 25% by air
  • Compaction describes when soil has been squashed into a solid impermeable layer, either at the surface or within the topsoil. This band of squashed soil restricts the movement of air, water, and nutrients down through the soil profile
  • For more information please click here

What causes compaction?

  • Soil composition and moisture content affect compaction, with wet and clay type soils being more prone to compaction
  • Ground pressure on soils imposed by tracks or wheels
  • Approximately 80% of soil compaction occurs during a machine’s first pass over loose soils
  • Poaching from livestock causes compaction, due to overstocking, or grazing animals in susceptible fields in wet conditions
  • Read more

How can I identify compaction?

  • Dig a hole to a depth of 30cm when the soil is not excessively wet or dry
  • Notice how far roots and moisture extend down the soil profile, and any obvious changes in soil structure
  • Pay particular attention of any areas where the spade meets resistance. The depth of resistance will help indicate the cause of compaction
  • For more information and to register for a free advice visit from the Soils for Profit scheme, in which compaction can be targeted, please visit the Soils for Profit page.
  • Watch the video at http://www.environment-agency.gov.uk/business/sectors/123420.aspx

Costs of compaction

  • It impacts on a wide range of processes that occur in soil leading to a reduction in yield from the affected field, increased nutrient loss and soil degradation
  • It reduces the ability of grass to utilise fertiliser as the roots cannot fully exploit the soil and reach the nutrients
  • It reduces the uptake of artificial fertiliser - if the soil becomes waterlogged this causes the fertiliser Nitrogen to convert into gases which are lost to the air
  • It reduces the availability of mineralised Nitrogen from soil organic matter and the Nitrogen fixing potential of legumes (including clover)
  • It reduces the crop germination rates, plant seedling establishment and crop emergence
  • Read more

How can I get rid of compaction?

Download document here.

What are the benefits of removing compaction?

  • Introduction of oxygen to the soil which improves biological and worm activity
  • The physical opening up of the soil structure improves surface drainage and absorption of slurry which helps reduce run off
  • Increased rooting activity which improves the plant’s ability to use nutrients and trace elements
  • More persistent leys with more grazing days per season, and less need for reseeding
  • A more effective microbial population fixes Nitrogen for free, and improves utilisation of applied fertiliser. Grass on uncompacted soil can recover 60% of applied fertiliser , whereas only 26% of applied fertiliser is recovered by the crop in compacted soil (Defra, 2000)
  • Well aerated soils warm up faster in the spring and recover faster after grazing and cutting
  • Increased yields – a potential grassland yield increase of up to 900kg DM/Ha in the following year after addressing compaction issues. A crop of grass silage (£30/t) would result in an extra £108/ha (2006)
  • IGER trials have shown that aeration and the removal of compaction can increase productivity in grazing swards by 26kgDM/Ha/day and also due to the physical opening up of the soil, reducing ammonia losses and boosting the nutrients available to the plant (2006)
  • Read more

Step 1: Extract the soil block

If it is loose soil, remove a block of soil about 15 cm thick or to the full depth of the spade and place the spade and soil on to the ground or a surface where it can be easily examined.

If it is firm soil, dig a hole slightly wider and deeper than the spade leaving one side of the hole disturbed. On the undisturbed side, cut down each side of the block with the spade and remove the block placing the spade and soil on to the ground/surface

Step 2: Examine the soil block

If the soil block is a uniform structure, remove any compacted soil or debris from around it. If there are two or more horizontal layers of differing structure, estimate the depth of each layer and make sure that you assign scores to each separately (see step 7).

Step 3: Break up the block

Gently manipulate the block using both hands to reveal any cohesive layers or clumps of aggregates. If possible separate the soil in to natural aggregates and man-made clods. Clods are large, hard, cohesive and rounded aggregates.

Step 4: Break up the aggregates

Break large pieces apart and look at the internal structure of the cross-section. A crumb-like appearance with rounded aggregates easily broken apart and embedded in a finer matrix indicates a well-developed natural structure and lower score.

If clods can be broken in to non-porous aggregates with angular corners it would indicate poor structure and therefore a higher score.

Identification of Soil Group

Source: Think Soils, Environment Agency

Identification of Soil Texture

Source: Think Soils, Environment Agency