Posts Tagged ‘cover crop’

International Fertiliser Society: Meeting Challenges through Innovation

December 9, 2012

Conference Cambridge Dec 2012.

What challenges?

The growing world demand for food. Scarcity of land and water. Ecological limits are almost reached. We must produce more with less environmental impact. Sustainable intensification.

Some believe that organic agriculture is the solution. But the production is too low. We need increases, not reductions. We need an ecologically better general agriculture.

What innovations?

Higher and more reliable yields. The ambitious English project Wheat 20-20 (20 tons/ha year 2020), a combination of plant breeding and agronomic development.

Better adaptation of inputs and resources. More efficient phosphorus fertilization, for instance placement (common in Sweden) and maybe foliar or seed application as complements.

Focus also on potassium and magnesium. Deficiencies, also shortterm, reduce stress tolerance and yields.

Cover crops. They reduce nitrate leaching and in addition provide organic matter and are positive for life in soils. They function also as break crops in rotations.

Manure is a great problem. Theoretically a good solution is to move animal production back to crop producing farms. Go back to mixed agriculture. But that does not work in our economic reality.

Two ways are worked on: to improve the manure efficiency at farm level and to process manure to marketable or at least transportable products which can be removed from the farm. However, it is not an easy problem to solve.

The longterm nitrogen efficency of manure is low. The most efficient method, injection,  has a longterm efficiency of 55% compared to mineral fertilizer. In practice the efficiency today is only half of that.

A problem mentioned is that economic realities often do not permit use of improved agronomic measures. This a big problem for the world development.


Catch crop effects in a wider context, cover crops.

November 21, 2012

Sweden has since several years a catch crop program. It has been focused on reduction of nitrogen leaching. A compensation is paid to the farmer to encourage the practice.

In previous posts on this blog the more general favourable effect of catch crops, on soil structure, on soil life, on organic matter content has been advocated. It is very encouraging that these issues now are discussed an recognized in an official report.

Catch crops can be transformed to cover crops, where even a harvest can be taken. Also this is mentioned, although the research and experience on this is scant. However,  at least in some favoured areas we can produce a second crop after for instance cereals.  Forage can be preserved as silage and used for biogas,  if  local biogas plants are established. In this way agriculture can substantially contribute to energy production and climate gas improvement.

Zero greenhouse gases from plant production – a possibility.

November 25, 2009

 Use of agricultural by-products as straw for bionergy opens up for a plant production with climate neutrality. The losses from soil and use of inputs will be compensated by the saving of fossil fuels in the total picture.

 However, there is a something to consider, the soil carbon. In most agricultural soils the soil carbon needs maintenance, and for that reason return of straw is important. But it can be replaced by cover crops, with advantage. Adapted in the right way we may get the following: Some yield increase, improved soil carbon and soil structure, soil surface protection, income from straw sales, in total low or even negative emissions of greenhouse gases for the whole system. Required base: a calculation of carbon balance and development.

A new authority for the Baltic?.

March 6, 2009

The issue shall be investigated according to a press release from the Swedish Secretary for Environment.

As expressed in this blogg the agriculture in Sweden is environmentally efficient. Not only the nutrient efficiency is high, the actual losses are low, comparably. But that does not mean that improvements not are possible.

Manure is mentioned in the press release. And there is a problem. The animals keep producing manure and nutrients which the soil not always needs. The rules of today have only stopped continued nutrient accumulation.

Clearly, it would be better for the Baltic if this production moved to Denmark or the Netherlands. This will probably be the result of new restrictions.

A couple of other proposals:

A crash program on manure treatment, transports and spreading technology. In the complete picture there are more gains than often believed. The receiving soil increases fertility and carbon content. This should be considered in the transport ecology. Greengard Farming Perspectives can be of help here. Also biogas alternativs should be considered.


Soil which is not disturbed from Autumn to Spring gives less erosion and moderates water flow. Nitrogen outflow is considerably reduced, as well known. There are many advantages. This was proposed in a workshop in January organized by the Environmental Protection Board, and is under consideration.


A picture of the situation in the Baltic (started by massive inputs of  N and P in the 1900s, inputs which continue from some areas):

A conflagration with lots of inflammable material is going on. On one side a group of desperate people with buckets and handsprayers try to improve their work, but on the other side another group is pouring oil in the fire.  (I do hope I am wrong).


In Science 20 Febr a Policy Forum (Controlling Eutrophication: Nitrogen and Phosphorus) it is stressed that both N and P should be reduced. The Baltic and the crucial influence of the P in bottom sediments is mentioned.


Competitiveness – soil carbon – cover crops – zero plots – precision farming – Agrotain.

February 12, 2009


Some topics which have been on the agenda the last few days.

The farmers´ organizations stress competitiveness, thinking of Swedish taxes and environmental rules. They are right, we have a problem. Only – one could wish for a wider view.

A well functioning soil also gives competitiveness. But a yield of 8 tons of wheat must imply a good soil? Maybe so, but it could have yielded 8.5.  Soil carbon helps, more organic material from for instance cover crops is positive for soil carbon and biological activity and also soil structure. There are important advantages to harvest.


Nitrogen is a strong agent – it has to be held in tight reins. With zero plots to characterize the soil and precision farming to adapt to the actual crop you are doing just that. But in for instance England there are other ways of development. Much urea is used which means risks for considerable ammonia losses. These can be reduced by means of chemical substance, an urease inhibitor. Market name: Agrotain. This improves the situation somewhat, but you could ask: is this the best way to go? Wouldn´t it be better to use available knowledge and technology to control the use of reliable N sources as well as possible?


Economy, environment and longterm considerations.

January 28, 2009



From the post below it may seem that these goals don’t go together. It can be so, but not necessarily. Often there are win-win situations and that is the idea behind Farming Perspectives.

An example from a cereal-oilseed farm in middle Sweden:

We use cover crops where possible, which is 3 years of 6. The are left over Winter and all soil management takes place in Spring. On many soils this is possible.

There are costs for seeds and for extra herbicides, say in total SEK 300. But instead there are savings in soil management, maybe 300. This evens out.

The cover crops increase soil carbon in the long term and biological activity directly. This may mean increased yields and income of SEK 100 – 200 for each crop.

With these figures there is a gain of  SEK100-200 per year.


Not very exciting, but something.


And further: Soil carbon is increasing meaning better soil structure, easier management and better yield security.

There will be less risk for erosion and phosphorus outflow.

Nitrogen is kept in the soil and leaching is reduced.

There is more life of all kinds in the soil and the landscape.


Is this idealized? Not in average. In the specific case it depends on the crops, the soil and other farm specific characteristics. And it should be observed that no subsidies or payments are included. They can be added in some areas.


Good prospects.

January 18, 2009


At present there are many reasons to feel optimistic:


Farming Perspectives – maybe a fresh development opportunity.

Precision farming – seems moving

Cover crop issue – maybe a start

Agricultural System experiments – possible to contribute to a good summary.


Also in perspective my summary of environment and economy from the last post seems workable.

If we take the example cover crops:

One way currently used in some areas is to give a subsidy. But there is bureaucracy, restrictions and a 5 year contract. Not only encouraging.

Another way is to sell the advantages to agriculture concerning soil productivity and environment. Further, to inform the consumers and the trade sector of the advantages of this production. They should feel a bit ashamed of less environmentally friendly cheap production. Use available means to support quality branding.


In the USA there is now trade of carbon dioxide contracts for agriculture ( ). Conservation agriculture in the Mid West is estimated to sequester 0.6 tons carbon dioxide per acre and the current price is about $4 per ton. This means about $5 per hectare. Not much but something. And the price might increase.


But the driving force for agricultural development should not be global price competition. That goes the wrong way.

The whole and the details.

January 8, 2009


The Swedish Environmental Protection Agency is arranging a workshop next week in order to squeeze out ideas for further reduction of emissions to The Baltic. That is needed, for large commitments have been made in Baltic Sea Action Plan.


It is about N and P. But I hope that the topic can be widened to include the integrated function of the soil. And that is almost necessary, since we have gone very far in correcting malpractices and errors. Few simple solutions remain. But there are possibilities to improve the functioning of the soil. Better structure, better stability and surface protection will help reducing P outflow. The very work in this direction will also reduce N outflow and greenhouse gases. Biodiversity and yield capacity will increase. Cover crops are more than just N catch crops.

Have a look at my post of 30 Dec.


In general, segmentation and specialization is a problem, both concerning authorities and research. Different units have there own segments. Integration is difficult. The economists should perhaps integrate, but also they have got specialized tasks.


A flower to Greppa Näringen (Focus on Nutrients) who has dared to integrate many aspects in “The soil fertility module”.

Cover crops – important also for biodiversity.

December 30, 2008


Compared with a bare, plowed soil, cover crops favour life both on the soil and in the soil. This is an important addition to what was mentioned yesterday.

Soil fertility and environment. Connections.

December 29, 2008


I am just now working with the following chain of connections.


When soil carbon is low, an increase is positive for soil fertility.

Increase in soil carbon can be achieved by means of cover crops, preferably over-wintering.

An increase in soil carbon improves soil structural stability.

Cover crops not only give raw material for soil carbon, they also provide fresh organic matter which increases soil biological activity, which also is positive for soil structure and fertility.

Soil carbon reacts slowly (decades), biological activity faster (year).

Which means: soil carbon building measures have a positive effect on soil structure both shortterm and longterm.

A more stable soil reduces dispersion in water flow situations and gives lower phosphorus outflow.

A more stable and better aggregated soil gives better infiltration and higher water holding capacity, which tends to reduce both surface runoff and total water outflow.

Less water outflow gives reduced outflow of both N and P.

Cover crops reduce the amount of nitrate in the soil profile and the leaching.

All these links in the chain work together to an end result: measures increasing soil carbon also reduce the outflow of  N and P.


Question marks and counter arguments:


Increased organic matter can increase N outflow. — Yes, but however the future management is arranged there will be a net reduction in total N outflow.


A crop in winter can release soluble P. — Yes, but in field experiments this has not been found. But needs further investigation. A compromise: shallow incorporation late autumn.


Too expensive and troublesome.—  Calculate! How much does a continous decline in soil fertility cost?


Cover crops will lead to more herbicide use. — Maybe. To some extent maybe worth it. To some extent possible to avoid by choice of crops and methods.


And there is another aspect: Greenhouse gases.

If an amount of 200 kg carbon is tied up as soil carbon, 720 kg GHG is tied up, comparable to the emissions when 240 l oil is used.

But this cannot go on for long? No, maybe 30-50 years. But those years may be important.

Nitrous oxide? Varying experimental data. Maybe overwintering cover crop is of advantage.