Only 3% of the UK arable area is farmed using Conservation Agriculture (zero tillage), much lower than other parts of the world. Anthony Pope argues why more farmers should consider this approach.
There has been a huge increase in agricultural productivity over the past 100 years, but the world must increase its food production by a further 60% in the next 40 years.
Feeding the world in 2050 and beyond will need additional crop production intensification and optimisation.
This will be challenging as productivity is being restricted by the increasing shortage of water, the availability and cost of mineral phosphate for fertilisers, the widespread decline in soil fertility, the limited land remaining for cultivation, and the impact of climate change.
Another challenge farming faces is its environmental footprint and the effects of climate change. To increase UK food production, the government supports a strategy of sustainable intensification, where farmland output is increased while reducing environmental harm.
But it must not only reduce the impact of climate change on crop production, but also mitigate the factors that cause climate change by reducing emissions and by contributing to carbon sequestration in soils.
That is why I believe conservation agriculture is a solution. It facilitates good agronomy, such as timely operations, and improves overall land husbandry. It is characterised by three linked and core principles:
- Minimal soil disturbance – through the use of no-till seeding to enhance populations and activity of soil macro-biota such as earthworms and reduce soil compaction
- Permanent soil cover – from crop residues, specially planted catch and cover crops especially legumes, and relay planting of main crops
- Crop rotation – as traditionally used to control weeds, pests and diseases and to enhance resilience against bio-stresses.
It means farmers have to be more knowledgeable with a greater understanding of soils, and with more attention to overall management detail. Complemented by other known good practices, including the use of quality seeds, and integrated pest, nutrient, weed and water management, Conservation Agriculture is a base for sustainable agricultural production intensification.
The result of increasingly intensive production is that the soil has been negatively aged in the UK, some estimate by as much as 5,000-10,000 years in the last 40 years.
It is also estimated that between 1980 and 1995, 18% of soil organic matter (SOM) in arable soils was lost, with a result that most UK arable soils contain less than 2% organic matter, when ideally they should contain 3-6%.
Conservation Agriculture is strongly promoted by the United Nations throughout the world, as a basis for sustainable production intensification for small and large scale farms, and to produce healthy soils.
More than 155m hectares of arable land is farmed with this approach in major agricultural regions such as Canada, US, Australia, Brazil, Paraguay, Argentina and Ukraine. This accounts for 11% of global arable crop land, and is increasing at 10m hectares each year.
However, in Europe the area under Conservation Agriculture is little more than 2m hectares of arable crops, including 200,000ha in UK farmed by about 1,000 farmers. But this is a small proportion of the total arable area, compared with many other countries around the world.
About half of Canada is in Conservation Agriculture and in the Western US, it has become the norm. This has taken place in just the last 25 years, since the dust storms of 1989. Paraguay is 100% CA, of which 70% is with small farmers and Western Australia has converted over 95% of its arable cropping.
Global uptake of Conservation Agriculture
|Areas in the world||Area under CA (million ha)||% of arable land|
It is also practiced by farmers in all agro-ecological conditions and on soils that vary from 90% sand (Australia) to 80% clay (Brazil).
Farmers in the UK are not averse to change. Economics drove the change from ploughing to min-till over the past 20 years, with the purchase of new equipment. However, this is effectively pulverising tillage, as we are still using big, heavy tractors.
Min-till has brought the compacted layer up to 10cm depth, with dust on top which cannot support crops during dry spells. Half of UK arable land has been converted to min-till with no environmental benefit, but with increased susceptibility to climate change.
Farmers drove the change, and equipment manufacturers responded; I believe the same can be achieved with Conservation Agriculture.
The challenge is to roll it out across the UK. Its slow adoption to date has been in the drier and more level eastern side of the country, where conditions are most similar to the countries noted above.
However, I believe it has much to offer to the more humid and hilly areas of the UK, where lower machinery inputs, improved soil cover and comprehensive crop rotations can enhance soil structure, reduce soil compaction, improve rainfall retention and help reduce water run-off, erosion, nutrient loss and flooding.
Conservation Agriculture can thus support sustainable and profitable agriculture through soil and landscape management, plus provision of broader ecosystem services.
I firmly believe that radical changes to farming practices are necessary in this country and elsewhere, using this approach to ensure a balanced system to improve soil organic matter and soil biota levels and enhance the sustainability of soils and hence, crop yields.
During my years of involvement in agriculture in many different countries around the world, my overriding concern has been to improve food security and agricultural sustainability:
- Crop yields have been falling and will continue to do so unless steps are taken to reverse soil erosion, soil degradation and the decline in soil fertility
- CA represents a practical concept (not a blueprint) to halt this downward trend and achieve improved soil health and better soil-crop-nutrient-water management leading to ecologically and economically sustainable agriculture
- In this country, generally low organic matter levels in the soil are being shown up by increased crop stress and wilting during the long dry spells that we have been experiencing, leading to very poor crop performance
- At the other end of the scale, we are seeing considerably more erosion and soil degradation with the increased intensity of rainfall that we are experiencing
Zero tillage, at the heart of Conservation Agriculture, has many advantages, including:
- Improved soil organic matter, soil porosity and the life of soil organisms and reduces the effects of compaction
- Improved availability of plant nutrients while using less fertiliser
- Control of weeds and pests with fewer agrochemicals, provided that intelligent targeted techniques are used
- Improved water absorption and groundwater recharge which reduces run-off and flooding
- Reduced labour/tractor inputs
- Reduced greenhouse-gas emissions from the soil and reduces farm fuel use
- Enables current yields to be sustained in the long term, thus reducing deforestation and releasing land for biofuels
- Reduced costs and increases profits.
One example is in Western Australia with its very extensive, low input and very low output system (wheat yields of 1.5t/ha). This system became unsustainable as climatic conditions worsened, input prices increased and producer prices dropped.
Conservation Agriculture was introduced and developed huge momentum, such that 95% of arable cropping in Western Australia is now following the principles, with wheat yields of 4-6t/ha regularly achievable in very dry conditions.
The transition phase for conversion to Conservation Agriculture usually takes about two to three years. However, the full benefits of the system often only become visible after five years.
Mechanical tillage is replaced by biological tillage (crop roots and soil fauna) and soil fertility (nutrients and water) is essentially managed through zero tillage, soil cover management, crop rotations and weed management.
A 240ha (600-acre) arable farm can be managed with one medium-sized tractor, a no-till seed drill, a combine/header and a sprayer. Some weeds and pests create specific challenges, but the health and diversity of soil biota help reduce the incidence of weeds and maintain a reserve of predators.
Improved soil life and cover has a dramatic effect on birds and other wild animals.
As already stated, Conservation Agriculture has been desperately slow at gaining a foothold in the UK farming system, and I feel that there is a huge need to foster:
- Research and academic discussion into Conservation Agriculture practices which will work with the varied farming systems in UK
- Development of pilot areas and experimental plots to test ideas
- Encouragement of farmers in all areas to adopt the new Conservation Agriculture principles and practices
- Commercialisation and development of best Conservation Agriculture practices across different parts of the country
There is real potential to take this approach forward with fresh-thinking farmer engagement, government support and the vital research, academic, best practice and business support.
I recently attended an excellent Tropical Agriculture Association visit to a farmer in Lincolnshire who has adopted Conservation Agriculture, and employed a no-till regime since 2003 on his three farms totalling 1,250ha. He has found that Conservation Agriculture crop production costs are around £130/ha compared with £266/ha for conventionally tilled crops.
Some of this saving is due to lower fuel bills as diesel consumption has fallen from 92 litres/ha to 42 litres/ha simply by adopting no-till; in addition, soil organic matter levels have increased as shown by the soil organic carbon (SOC) level which was 2.1% in 2003, 4.6% in 2007 and is now 6.3%.