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Case Study: The Cross Slot Drill with Paul Alexander


Overseeding is ideal if grass is tired or if a pasture has lost its vigour and needs rejuvenating, and is also a way of introducing a different or more productive species. There’s lots of talk at present about the benefits of ‘no til drilling’ and in many ways Paul Alexander is at the cutting edge. Paul runs Prime West Ltd, farming 1000 acres in Oxfordshire with a combination of 800 acres of organic and 200 acres of conventional crops. But his influence spreads further afield thanks to his Cross Slot Drill which is much in demand from farmers wanting to overseed an existing pasture.

The Cross Slot Drill was developed at Massey University in New Zealand to introduce new seeds with minimal disturbance to the biology of the soil. What gives it it’s name, and is it’s true unique feature, is a disk and winged blade running alongside the disk. The Drill works by lifting a horizontal flap of soil, leaving a small slot with a ledge onto which seeds can be placed before the slot is closed very efficiently.

Paul arranged to have a 3m drill imported from New Zealand and after modifications the three drills Paul and his team now operate are much in demand, particularly for overseeding.  One of the main advantages of the Drill is extremely low disturbance to the soil, avoiding destruction of  the soil structure and loss of moisture caused by conventional ploughing. All that can be seen after drilling is a narrow slot in the ground.

When combined with the benefits of over-seeding it’s proving a popular option. Overseeding is ideal if grass is tired or if a pasture has lost its vigour and needs rejuvenating, and is also as a way of introducing a different or more productive species or a legume into the sward, such as clover. Overseeding is also much cheaper than a total reseed, with much lower fuel costs than ploughing a whole field. The pasture is ready to use again much quicker and it has a firmer surface which reduces the impact of livestock poaching in poor weather.

Because the blade in the Drill runs really tight to the disk it’s unlikely to block up with debris, allowing drilling into all kinds of residue. A press wheel controls the depth and and seals the slot back up again while ground radar varies the speed of the metering system and enables the drill to cope with uneven fields and even drill into ridge and furrow, even if the soil is heavy or stony.  The Drill also enables land to be sowed at a prescribed depth which is important for overseeding with small seeds like clover or grass, or for stitching herbs into an existing ley. 

 The organisation BASE (Biodiversity, Agriculture, Soil and Environment) is aimed at sharing knowledge and experiences connected to carbon management, minimum soil disturbance and increasing residues in the soil. It  is in favour of  this practice which breaks the cycle of heavy cultivation that reduces the carbon stored in the soil and can lead to the loss of soil organic matter.


Date Posted: 30th March 2017