History of Strip Tillage
Whilst the Mzuri system is celebrating its 10-year Anniversary in 2021, strip tillage as we know it is a time-honoured concept that dates back throughout history. Starting at the inception of modern-day agriculture, we take a look at the history of conservation tillage through the years and what influenced the design of the Mzuri Pro-Til.
Jethro Tull invents a method for sowing seed in rows
Pre-dating the modern rock band, Jethro Tull was a British Agronomist and Inventor who in the early 1700’s developed a seed drill that sowed seeds into rows removing the need for hand seed placement. Tull’s seed drill worked by combining three elements, a leading leg to create a tilled row, a seed delivery mechanism that delivered seed into the till, and a basic harrow that covered the seed. What was a clear example of the basic strip tillage principle in practice, Tull sought inspiration from vineyards in France where by cultivating strips of soil between the vines they were able to reduce the need for manure. We now know this to be the effects of mineralisation but at the time Tull was widely criticised for not using artificial manure and believed that the earth was the sole source of food for the crop. Despite his views on fertiliser, his developments into seed drills formed the basis on which modern day agriculture has been built.
Moving on from Tull, combining seed and fertiliser placement
Whilst Tull had opened the door to a new method of crop establishment, later developments such as the Walker drill looked to combine fertiliser and seed placement whilst building on the basic strip tillage principle. The Walker drill was designed to establish Mangels and Turnips and featured two in line legs which deposited ‘manure’ down the front coulter and delivered seed down the second coulter. It is striking that even at this early time, the importance of separating the fertiliser and seed was well known as explained in their brochure – ‘The manure and seed are deposited through separate colters, as illustrates, injury from strong manures thus avoided.’
Dust Bowl in America sparks the need for Conservation Tillage
With the advent of agricultural expansion and mechanisation in the Southern Plains of America, over cultivation of the areas fragile soils caused severe dust storms and drought. Prompted by an increase in demand from Europe during World War I, wheat prices rose, and farmers looking to maximise their returns responded by ploughing millions of additional acres to cereal production. But with the onset of the Great Depression, wheat prices fell, and farmers ploughed even greater acreages in an attempt to increase their output and break even. Many farmers at the time believed that “rain follows the plough”, but when drought in the early 1930s caused crops to begin to fail, the overcultivated, exposed soil simply blew away. Without the protective native grassland, which had preserved the soil for centuries before, the Southern plains became a desolate landscape that made conventional agriculture almost impossible. It was this that largely prompted a return back to simpler, more sympathetic farming practices that went on to be defined as tillage methods such as conservation tillage, strip tillage, band tillage, ridge tillage, slit seeding, mulch tillage and many more.
1960’s – 1970’s
Major manufacturers patent and develop strip tillage techniques
With the importance of conservation establishment methods highlighted during the 1930s, major machinery manufacturers such as Massey Ferguson, John Deere and International Harvester continued to develop machinery that tilled and seeded in strips between rows of uncultivated soil. Such examples of these machines included the Case Chisel Planter which featured a row of chisel tines followed by seeding coulters which established crops into uncultivated stubble to preserve soil structure, retain moisture and reduce establishment costs. With fragile soils not specific to America, there are many examples of similar machines being patented and developed during the 60s and 70s including several examples in the UK.
Standing straw recognised as important tool to protect light soils and crops from Fen winds
In the UK through the 1970’s, further developments were being made in conservation farming including an innovative technique to plant straw to protect fragile soil and crops in the East of England. Designed by the Shropshire Family based in Ely, Cambridgeshire the straw planter inserted straw between rows of salad crops to protect them and the light soil from the destructive fen winds. This was an ingenious system for the time and highlighted the vulnerability of these soils bearing resemblance to the challenges faced in the Southern Plains during the 1930s.
Norfolk Peat calls for further strip tillage development
Not too far from the work in Cambridgeshire, the Norfolk Agricultural Station (NAS) was also trialling conservation techniques including strip tillage in sugarbeet production.With similar fragile soils, the work aimed to reduce wind erosion and improve moisture available at drilling. To achieve the strip tillage technique, the NAS used a straight blade rotavator set to cultivate bands 18cm wide and 4-5cm deep, leaving the remaining 32cm between the rows undisturbed. In front of this was a 2cm tine to loosen the till at depth and behind the rotavator followed Stanhay seeding units. All of the elements were arranged in line to allow the drill to cultivate, seed and reconsolidate in five bands, whilst leaving undisturbed soil and straw in between each row. This machine cleverly used the technique of independent seeding units as photographed in 1977. The results of the trials were widely reported and further developments went on to replace the rotavator with a fixed tine to cultivate the strip ahead of the seeding units.
1970’s – 1980’s
Popular farming press publications reported conservation tillage as being ‘in vogue’
Throughout the late 1970s and 1980s popular national farming magazines such as the Farmers Weekly and Power Farming reported increasing popularity with conservation tillage. By now the vocabulary surrounding these techniques expanded to include minimum tillage, zero tillage and no tillage amongst others, which represented a varying degree of soil disturbance.
1980’s – 1990’s
Disc direct drilling gains traction but crop residue proves problematic
By the 1980s, direct drilling and minimum tillage were gaining popularity for their ability to significantly cut fuel, labour, and other establishment costs. However, the ban on stubble burning in 1993 meant that many of these direct drills, particularly those that used discs were no longer able to perform as well with the increased crop residue now left on the surface of the fields. Unlike America, which was where many of these systems came from, crops in the UK are generally higher yielding and subsequently produce more crop residue which many direct drills at the time were not built to cope with.
Seed Hawk launched with individual coulter control
In 1992 Seed Hawk launched their direct seed drill which combined a leading cultivating tine which placed fertiliser with an in line following coulter to drill crops direct into stubble. This marked the start of a new breed of minimum tillage drills which featured individual depth control wheels to the rear of the coulter enabling precise seeding depth. It was actually the Seed Hawk that influenced the rear coulter wheels on the Mzuri Pro-Til for their ability to provide even seeding depth across the width of the machine even over undulating terrain.
Subsoiler establishment for Oilseed Rape proves popular
During the 2000s the technique of seeding Oilseed Rape using a subsoiler was becoming increasingly popular and was used on our own farm with good success. This method was yet another example of strip tillage and followed closely the principle developed by Jethro Tull by creating a trench into which seed is distributed. By only cultivating strips rather than blanket cultivation across the field, we were able to retain moisture within the soil aided by keeping the previous crop residue on the surface. This was vital for quick germination in late August which at one of the driest times of the year is when OSR is typically drilled. This simple method of establishment which went back to the roots of modern agricultures as we know it, was a foundation on which the Mzuri Pro-Til was developed.
From everything we knew about the history of conservation tillage, the Pro-Til was designed to combine what we believed to be important key features that have been tried and tested throughout history. We recognised the importance of fertiliser placement below the seed so we incorporated this into the design of our leading leg to provide narrow tilled and fertilised strips between untilled soil.
Another important feature of the Pro-Til is that the leading tines are followed by a unique row of reconsolidation wheels which firm the tilled strips to provide the perfect nursery seedbed. This row of wheels not only removes air pockets from the till, but also evenly bears the weight of the whole machine.
Into this carefully prepared tilled zone, the Pro-Til’s unique independent seeding arms, each fitted with a rear depth wheel and typically a wide wing coulter, place seed in two bands equally to the side of the tilled zone at a very accurate depth.
It was becoming more and more important for manufacturers to develop machines that could offer growers accurate seeding depth due to the increasing regulations surrounding seed dressings and pre-emergence herbicides. With specifications for seed depth being in the millimetres, to comply with the legal statute associated with using these products, it made individual seeding depth control a basic requirement in drill design.
An additional unique benefit to ensure we maintain accurate seed placement aligned with each tilled strip made it necessary to include our patented pivot to each of the individual coulter arms. This coupled with the individual rear depth wheels acts as a steering system which automatically lines the centre of the coulter with the centre of the tilled strip, even across sloping banks or around headland corners. It is this unique combination of features that, whilst built on a rich history of strip tillage, makes the Pro-Til unique.
1. Optional front disc to cut through surface residue
2. Auto reset leading tines ensure good root developmentand cleans the sowing strip of surface trash to produce a clean till of moist friable soil
3. Band placement of fertiliser below the seed reduces fertiliser requirement and ensures early nutrient accessibility
4. The staggered wheels remove air pockets and reconsolidate the tilled strips
5. Excellent soil to seed contact is achieved by hydraulic pressure exerted to each individual seed depth wheel
6. Individual depth adjustment to each of the semi-pneumatic coulter depth wheels accurately controls seed placement
7. Hydraulically operated adjustable pressure harrow ensures a level uniformed seed bed