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[Fwd: Re Ang email and reply to the ORganic magazine article]

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  • Richard Morris
    Ang and pfaf group, Heres and email from one of the VON people which includes part of their handbook on stockfree-Organic growing. Rich From: jenny hall
    Message 1 of 1 , Aug 30 3:33 AM
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      Ang and pfaf group,
      Heres and email from one of the VON people which includes
      part of their handbook on stockfree-Organic growing.

      Rich

      From: jenny hall <jennymosscentre@...>
      To: p.a.white@..., webmaster@...

      Dear Richard

      Sorry that this is quite academic it was more bombarding Ang with
      information rather than answering the question directly. I have offered to
      write Ang a considered response but haven't actually seen the article where
      vegans are supposed to be "unnatural" I told Ang to quote that the HDRA and
      NFU magazines have declared vegan-organic farming a success using Tolhurst
      Organic Produce as an example a 17 acre market garden in Reading which
      serves 350 box scheme customers and employs 5 people.

      Richard can I use parts of the article on woodland edge in the Handbook on
      Stockfree-Organic growing. If so can I use the text which will be fully
      credited to PFAF / you in the format you want.

      Best wishes

      Jenny Hall


      Extracts from the handbook

      Vegan-organic supporters have an uphill struggle in dispelling the
      following
      myth.

      It is not possible to build up soil health and grow organically without
      animal manure.

      This is untrue, as it would be thermodynamically impossible for all
      fertility to originate from animals. Animals do not have the ability to
      produce new plant fertility. Plants alone are the producers of food energy,
      and of soil humus, and all animals, including humans, are net consumers. We
      may convert and concentrate food energy and thus fertility in our bodies
      and
      wastes, but we are net destroyers of it.

      No one is denying that animal manures and slaughterhouse by-products
      fertilise the soil and yield crops. However, the fertility does not
      originate from these residues, but rather from the grass and grains which
      the animals ate. The animal destroys the greatest part of that food energy
      by its digestion, metabolism and other life processes. Only a small portion
      of that life force can be preserved within the meat, milk products or
      manure
      of that animal.

      ****

      The International Federation of Organic Agricultural Movements (IFOAM) had
      its first conference in 1977 and charged itself with laying down the
      fundamental principles of organic systems. These were later agreed in 1982.

      The IFOAM principles of organic agriculture are:
      1. to work as much as possible within a closed system and draw upon local
      resources.
      2. to maintain the long-term fertility of soils.
      3. to avoid all forms of pollution that may result from agricultural
      techniques.
      4. to produce foodstuffs of high nutritional quality and sufficient
      quantity.
      5. to reduce the use of fossil energy in agricultural practice to a minimum.
      6. to give livestock conditions of life that conform to their physiological
      needs and to humanitarian principles.
      7. to make it possible for agricultural producers to earn a living through
      their work and develop their potentialities as human beings.
      8. to use and develop appropriate technology based on an understanding of
      biological systems.
      9. to use decentralised systems for processing, distribution and marketing
      of products.
      10. to create a system which is aesthetically pleasing to both those within
      and those outside the system.
      11. to maintain and preserve wildlife habitats.

      The vegan-organic system is also based on these principles with the
      exception of No. 6. However, as will be argued, the rearing of livestock in
      organic agriculture to promote good health and soil fertility could be at
      odds with principle 3 (with cattle producing polluting methane),
      principle 4
      (producing sufficient quantity of food for world populations) and principle
      5 (minimising the use of fossil fuel).

      1.7 Can organic systems feed the world ?

      According to the State of the World Report in 1999 the world's population
      passed the 6 billion mark. The UN predicts 4.6 billion more will be
      added to
      this in the 21st century. Not only is the overall global population
      increasing, but the increase is taking place in the developing
      countries. By
      2050 another 600 million people will live in India, another 300 million in
      China. Yet, 2 billion people are presently malnourished.

      More and more people will live in urban centres. As economic conditions
      improve, people demand more animal products in their diets. A study
      commissioned by the Commission of the European Union, World Bank and
      various
      governments shows that urban populations consume more meat per person than
      rural populations. The overall human demand for animal products is expected
      to triple or even quadruple in the next 30 years.

      It is questionable whether it would be physically possible for all the
      world's estimated future population to eat animal products at the same
      level
      as, say, the USA today. The State of the World Report in 1999 estimated
      that
      for 10 billion people to eat a US diet, we would need 4 planets the size of
      Earth to produce the extra 9 billion tons (US) of grain required. In the UK
      80% to 90% of the 46 million acres of agricultural land is used to feed
      animals. At present livestock consume 38% of the world's cereal production.

      As Maneke Gandi, the then Indian Minister for the Environment argued:

      More grain is fed by the USA and USSR to livestock than is consumed by the
      people of the entire third world. Britain gives two thirds of its home
      grown
      cereals to its livestock – that amount could satiate 250 million people
      each
      year. Even then it imports grain for livestock … including soya beans from
      India who provides every tenth of milk and every tenth pound of meat
      produced in the EEC….”

      Water is a dwindling resource in many parts of the world, for every
      litre of
      water used to produce a kilogram of rice it takes one hundred thousand more
      litres to produce a kilogram of meat – taking into account the water the
      animals drink, the amount used to grow their feed and in slaughtering and
      processing.

      The most obvious way of tackling these problems is for humans to eat more
      efficiently and lower down the food chain i.e. all arable land should be
      directed to food for human consumption. A person consuming a plant-based
      diet uses about an eighth of the land that an omnivore does.

      Lawrence Woodward, the Director of the Elm Farm Research Centre has written
      the following briefing paper "Can Organic Farming Feed the World?" Although
      he is not looking at this from a vegan-organic viewpoint, the following
      passage is instructive.

      "During a recent exchange we had with the Department of Agriculture in
      Malawi, they rightly pointed out that organic farming has little to offer
      intensive maize plantations or any other capital intensive monoculture
      commodity production system used to trade and raise foreign exchange.
      Organic farming was therefore dismissed "as only good for small scale,
      local
      vegetable production". But this is what feeds people.

      It is easy to dismiss this approach as extreme and forget that the "Dig for
      Victory campaign during the [second world] war was a very important part of
      the British Government's efforts to ensure food security and health. The
      garden and in particular, biologically-intensive gardens are more
      productive
      in terms of nutrients per hectare than any "farming" system.

      Organic farming based on locally adapted, intensive biological systems
      works
      extremely well and can be highly productive, particularly across a range of
      basic food crops. [Organic methods] are stable and relatively secure on
      vulnerable soils and in volatile climatic conditions due to their focus on
      living organic material, which provides a buffer for soil and water. As
      such
      they are very appropriate to Southern countries. There are of course
      problems in some regions. Pests and diseases are a threat. In such cases,
      cropping diversity reduces the threat and spreads the risk, thus ensuring
      stability and security. Organic farming founded on a technical level can be
      seen to provide adequate food in all parts of the world. Where it doesn't,
      issues such as access to land and political problems, including the role of
      women are often the major obstacles. [These are] matters of power and
      economy not technical issues".

      ***

      3.3.1 Managing nitrogen

      Nitrogen in the soil has six possible routes. The vegan-organic grower
      wants
      to manage the first three and avoid the others.

      1. Mineralisation and used by a subsequent crop - In relation to plant
      nutrients mineralisation of elements like nitrogen and phosphorus means the
      conversion of relatively complex insoluble organic compounds into
      relatively
      simple water-soluble inorganic compounds, which can be absorbed by plant
      roots or leached out of the soil. In organic systems the soil
      micro-organisms account for about 37% of nitrogen mineralisation.
      Mineralisation is most active when the soil is at its warmest in the summer
      months.
      2. Immobilisation - occurring all the time, nitrogen becomes bound by the
      soil micro-organisms in organic matter complexes to be later mineralised.
      3. Excess mineralisation - occurs when there is not enough organic
      matter in
      the soil. The carbohydrate content of humus provides the energy source for
      the soil micro-organisms and, if there is insufficient, there will be a
      stage when excess nitrogen ions become available, known as net
      mineralisation. The crops will have sappy, leggy growth and will be likely
      to suffer pest attack.
      4. Nitrogen lock-up (excess immobilisation) – a temporary event, likely
      when
      turning in a carbon-rich green manure like a cereal (see 2.4.2).
      5. Leaching - If there are no plant roots to take up the nitrogen, it will
      leach away. Nitrate ions are very soluble in water and are quickly leached
      from the soil by rain or irrigation water. In this way, nitrate is rapidly
      carried deep down into the soil, where it can no longer be reached by plant
      roots or is carried to waterways where it can become a pollutant.
      6. Denitrification - This typically occurs in anaerobic conditions, where
      there are no air spaces in the soil because it is either waterlogged and/or
      compacted. The nitrate ion is converted by denitrifying bacteria into
      nitrogen gas that then drifts off into the inert atmosphere. The bacteria
      are responding to a lack of oxygen for respiration by breaking down the
      nitrate to meet their oxygen needs.

      3.3.2 Recovering P and K

      A criticism levelled at vegan-organic systems is that they do not address
      phosphate P and potash K shortages.

      The problem with phosphorus is lack of mobility. Phosphate has to be in an
      acceptable form to a plant and as it cannot move in the soil, the roots
      have
      to move to the P. This explains why mycorrhizal association will help
      improve phosphate uptake.

      Fortunately potassium is one of more common elements in rocks. Clay soils
      will usually contain adequate potassium. Sandy and peaty soils have much
      lower reserves.

      In most organic farming publications animals manures are cited as the best
      available sources of P and K. When using animal manures, the P and K comes
      from the grass and animal feed, and, whilst it may be improving P and K
      levels on an individual farm, if the feed is grown off the farm, there is a
      shortfall somewhere. Increasing the levels of P and K on one farm simply
      results in lowering levels on another farm.

      The long-term strategy must be to work within closed systems on the
      individual farm where soils have high humus levels, to encourage
      micro-organism activity to release these nutrients. In vegan-organic
      systems:

      • adding straw to compost heaps will help recover P and K;
      • adding wood ashes to compost heaps will help recover K;
      • using deep rooting green manures like lucerne, red clover and lupins will
      help bring P and K up from the subsoil;
      • surface mulching with straw presents betters daytime conditions for crops
      to take up P and K (see 3.6.3);
      • the soil pH is kept between the values of 6.0 and 7.0 to encourage the
      maximum uptake of P and K;
      • mineral amendments (see 3.9) can be used to address shortfalls;
      • potash boosts in the form of liquid comfrey feed (see 3.9.1) can be used
      to address shortfalls.

      *********

      BASICALLY VEGAN-ORGANIC GROWING RECOMMENDS THE COMPLEMENTARY TECHNIQUES OF
      COMPOSTING AND GREEN MANURING AS THE PRIMARY SOURCES OF SOIL FERTILITY.

      Organic matter is the product of living matter and the source of it. It is
      an end product of all life processes: animal and human faeces, food
      processing wastes, domestic wastes, crop or vegetable residues, even dead
      bodies yet at the same time it is the beginning of new life, brought about
      through the agency of soil micro-organisms.

      The vegan-organic grower needs to increase the organic matter content by:

      • managing a compost heap outside the cropping area and applying finished
      compost to the cropping area;
      • turning in green manures (see 2.4.1 and 2.4.3) and other plant materials;
      • applying mulches (see 3.6.3).

      The advantage of the first method is that year-old compost quickly comes
      into equilibrium with the soil, whereas turning in residues will cause
      disruption to soil processes e.g. carbon-rich green manures causing
      nitrogen
      lock-up (see 2.4.2).

      According to Iain Tolhurst (reprinted with kind permission from the Soil
      Association) composting organic waste is an important task of the
      vegan-organic grower, because the health of the soil depends on the growing
      treatment it receives. This has been qualified by the Organic Growers of
      Durham who argue that in mulching systems composting operations are
      unnecessary.

      3.4.1Compost application rates

      • Maintenance application - 35 tonnes per hectare / 14 tons per acre / 1
      barrow load per 3 metre square every second year

      • Infertile soil application - 70 tonnes per hectare / 28 tonnes per acre /
      2 barrow loads per 3 metre square to in Year One whilst not infringing the
      government advice. If you are also using green manures revert to the
      maintenance application by year three.

      Compost applied to the soil has the indirect benefit of becoming the food
      source for earthworms and the energy in general for the soil
      micro-organisms. Earthworms have been burrowing through the earth for about
      200 million years. In huge numbers they swallow semi-decomposed organic
      matter and transform it in their gut, with the aid of tiny pebbles, into
      worm casts. Worm casts are up to five times richer in available nitrogen,
      seven times richer in available phosphates and eleven times richer in
      available potassium than the soil itself. Surface castings prevent
      crusting. The casts contain silicic acid, which is essential to plants for
      the healthy growth of cell walls. Through their burrows, which may go down
      as far as 7 metres below the surface if the soil is that deep, they
      bring up
      nutrients from the subsoil.

      Year-old compost will also inoculate the soil by adding a whole range of
      new
      micro-organisms. The role of the microscopic soil life is poorly
      understood.
      It is still not even possible to obtain an accurate survey of soil fungi
      populations. But at least it is known that, there are four tonnes of
      micro-organisms in one acre of fertile soil. The microbes have a role to
      play in decomposing organic matter, mineralising plant nutrients, making
      trace elements available to plants, nitrogen fixation, producing substances
      beneficial for plant growth and helping plants resist attack.

      3.5 Recommended - cut and mulched green manure strips, areas or leys



      Stockfree- Organic standard 3.2(b) Recommended - cut and mulched green
      manure strips, areas or leys
      Wider environmental impact Avoids transporting bulky organic wastes.
      Organic matter (carbon) locked in the soil and not in the atmosphere. where
      it would be adding to greenhouse gases.
      Advantages for the grower in terms of fertility Nitrogen fixation.
      Mowing and mulching returns organic matter to the soil.
      Mowing and mulching provides conditions for earthworm breeding.
      Use increases soil micro-organism activity.
      Deep roots recover P and K from the subsoil.
      Disadvantages for the grower Need to learn green manure management skills
      for vegan systems.
      Possible nitrogen lock up.
      Land out of production.
      Seed can be expensive.
      Establishment and regular mowing costs.

      Iain Tolhurst argues that, in an ideal world, all the soil fertility should
      be provided by compost but in practice this is impossible. Shortages of
      raw
      materials and the problem of selling crops off the holding, combined with
      losses due to leaching and oxidisation means that there will always be a
      shortage of compost available. To maintain organic matter levels in the
      soil, therefore, growers must also rely on extensive use of green manures,
      particularly legumes for nitrogen and deep rooting plants for the recovery
      of phosphate and potash from the subsoil. Green manure leys down for at
      least two years are the most important agricultural method for improving
      earthworm populations.

      3.5.1Legumes for building nitrogen supplies in the soil

      Nitrogen fixation by grass/clover leys is the single most important
      input of
      nitrogen into organic farming systems in the UK. Nitrogen fixation by soil
      micro-organisms is essential to the cycling of nitrogen out of the
      atmosphere and into the environment occupied by living organisms. There are
      a group of nitrogen-fixing bacteria of the rhizobium type, which have a
      special intimate relationship with leguminous host plants - peas, beans,
      pulses, peanuts, vetches, lupins, lucerne and clover.

      The rhizobia live in a free state in the soil and exist quite happily in
      this way until a legume is planted into the ground close to where they are
      living. As the legume seedlings develop, their roots start to secrete
      substances into the soil which attract the rhizobia nearby. The bacteria
      eventually enter the roots and stimulate the formation of swellings, called
      nodules, inside which the microbes multiply. At the same time, the bacteria
      take on different shapes to such a degree that they no longer look much
      like
      the soil rhizobia from which they came. For this reason, in the roots they
      are called “bacteroids” and these now have the ability to fix nitrogen from
      the air.

      In exchange for a share of the legume’s sugars manufactured by the leaves
      and stems of the plants, the bacteroids pass on nitrogen in a usable
      form to
      the host plants and leave a surplus in the soil to taken up by subsequent
      crops. Since the nitrogen cannot be picked up and moved around, as you can
      do with compost, the crops are brought to the nitrogen through the
      design of
      a suitable rotation.

      Nitrogen fixation by different legumes (kg/ha) :

      • Lucerne 300-550
      • Red clover/grass 230-460
      • Field beans 155-285
      • White clover/grass 150-200
      • Field beans 150-390
      • Peas 105-245
      • Lupins 100-150
      • Vetches 60-90

      3.5.2 Carbon-rich green manures for building humus

      Turning under young lush green manures will add immediate nitrogen and
      stimulate activity in the soil but will not generally boost the organic
      matter levels. On the other hand dry, carbon-rich residues like cereals and
      straw will take longer to break down but will boost the humus reserves.
      Carbon-rich green manures will decompose faster if they are chopped,
      shredded and kept moist before they are incorporated into the soil.

      3.5.3 Green manures for all occasions

      Green manures increase fertility and get life back into the soil. Like any
      organic crops, green manures should not be grown in endless monoculture, as
      they have their advantages and disadvantages that will affect the soil and
      following crops in rotation.

      Ley for building fertility before heavy feeding crops Grass with red clover
      / lucerne
      Catch crop for maximising nitrogen fixation Crimson red clover
      Resistance to foot traffic soil damage in crops Vetch and white clover
      Paths White clover
      Undersowing greenhouse crops Kent wild white clover
      Overwinter green manure that is winter killed Vetch, spring oats, spring
      barley, phacelia, buckwheat, mustard
      Late autumn sowings Cereals in general
      Weed suppression Phacelia
      Reducing wireworm populations Mustard


      Table 3.2 Recommended nitrogen fixing green manures by growers

      Green manure Suitability dates Field sowing per hectare/per acre Hand
      sowing
      per metre squared
      Notes

      Lucerne Apr-July 12 kg /
      5kg 15g grams Good perennial ley, sow with grass, needs a high pH and well
      drained soil.
      Red clover April - E Sept 7-12kg/ 3kg - 5kg
      1 - 2 grams Good perennial ley, roots have many branches and a taproot,
      high yielding in terms of green matter, rapid recovery after mowing, ensure
      eelworm free.
      White clover April - E Sept 6-10kg/ 2.5-4kg 1 - 2 grams Shallow rooted, low
      growing clover suitable for paths. Need strong growing varieties to recover
      from mowing.
      Crimson red clover July - E Sept 6-10kg/ 2.5-4kg 1 - 2 grams Annual, best
      for N fixing between crops, does not recover after constant mowing.
      Kent W White Clover April - E Sept 6-10kg/ 2.5-4kg 1 - 2 grams Low growing
      clover suitable for greenhouse crops trim with shears.
      Vetches April - E Sept 90 kg/ 36 kg 40 gm Winter-killed, deep rooted,
      produces a large weight of green matter.
      Lupins April - E Sept 50 kg/ 20kg 20 gm Use as an annual, fast growing, low
      frost tolerance.


      3.5.7 Green manure strips for fertility

      Langerhorst method - developed by the Langerhorst family in Austria from
      the mixed cropping system developed by Getrud Franck (see section
      2.10.2) is
      a technique that involves growing vegetables in widely spaced rows, at a
      fixed row spacing, and growing a legume (typically white clover) between
      the
      rows. The following season all the rows are moved long by a distance equal
      to half the row spacing, so that crops are growing where there was green
      manure last year and the green manure is grown where last year's crops were.

      Tolhurst technique for onions in the field - Onion sets are planted into a
      cleared seedbed through black plastic sheeting (which is secured by digging
      the edges in to the ground) with 30 cm / 1ft strips between the lengths of
      each plastic sheet. Red clover is sown broadcast into the bare soil left by
      the tractor wheelings between the onion beds in July, where it grows
      quickly. This has a beneficial effect on the onions, due to the nitrogen
      transfer between the strips and also on the subsequent crops the next year.

      Tolhurst technique for courgettes in the market garden - The Tolhurst
      market
      garden rotation is discussed in detail in section 6.3. In the previous
      year,
      runner beans on a wide spacing are undersown with red clover. Once the bean
      haulms have been removed, a stand of red clover remains. The next year
      several 60cm / 2ft wide strips are taken out of the red clover, with a
      pedestrian-operated rotavator, to leave a seedbed. Courgette transplants
      are
      planted into the bare earth and regularly hoed to keep down the red clover
      and the weeds. Once the courgettes are established, the red clover is
      allowed to grow back, enveloping the crop, with occasional bare patches
      being undersown with the red clover. The red clover is left throughout the
      following growing season to form a green manure ley most of which will have
      been in situ for three years.

      Clover strips for mowing - Growing clover in strips, next to vegetable
      beds,
      makes it easier to manage its growth because there is no possibility of
      root
      competition with the crops. At the Swedish Agricultural University, Alnarp,
      and at the Institute of Agricultural Engineering, Vakola, Finland they have
      been developing dedicated mowing and spreading equipment. A strip of clover
      is mown by an adapted flail mower and then the remnants of the clover are
      spread onto the vegetable bed to provide a complete cover around the
      vegetables providing effective weed control.

      3.5.8Overwinter green manures for fertility

      If a stockfree-organic grower learns nothing else, it must be remembered
      that the greatest loss of nutrients is due to leaching and not crop
      off-take. As seen in Table 3.1 vegetable growing makes heavy demands on the
      soil and there is no point in building fertility and then allowing it to
      wash away with the winter rains. Green manures will "fix nutrients in
      carbon" in the aerial parts of the plants and, even if the green manure
      dies
      over the winter, the nutrients are still stored, until the soil
      micro-organisms break them down, and are unlikely to be leached.

      • The autumn-lifted crops that are not suitable for undersowing (see table
      3.5), can be followed by a green manure once the soil is cleared. In
      field-scale growing this will typically be potatoes and onions.

      • Depending on the month it may be possible to sow:
      • clover before early September;
      • cereals from mid September to early November.

      Legumes do not fix nitrogen during the winter months. Therefore,
      non-legumes
      like cereals are more suited the role of overwinter cover, as their early
      growth is vigorous and they can establish themselves quickly.

      3.5.9 Undersowing green manures for fertility

      Undersowing green manures will, even in a growing crop, add some nitrogen
      and organic matter to the soil. But, as Iain Tolhurst argues, its real
      value
      comes in ensuring that the soil is covered prior to the winter period, when
      so many nutrients will be lost from the soil due to leaching.

      Preparing for undersowing
      Eliot Coleman’s tips for successful undersowing include:
      • A clean, weed-free seedbed providing the motivation for regular hoeing;
      • At least three surface cultivations should be made with the hoe before
      undersowing;
      • The last surface cultivation should be the day before undersowing.

      Undersowing using a drill
      Eliot Coleman recommends drilling the green manure. As well as a single row
      pedestrian pushed drill, he has invented a pedestrian pushed multi-row
      drill
      which consists of five Earthway Precision garden seeders bolted together
      with a common front axle and a common push-bar joining them. The tool has a
      total width of 50cm / 20" which fits in well between the 75cm / 30"
      spacings
      at which he plants his sweetcorn, beans and brassicas. All five hoppers are
      filled with either the same seed or a combination of legumes and grasses.

      Undersowing using a broadcast method
      Iain Tolhurst finds the broadcast method quicker.

      • Field scale - vegetables are grown on ridges and spring tines are taken
      between the ridges to aid weeding and to provide a seedbed for the green
      manures. The crops are then undersown using a seed fiddle.
      • Garden Scale – crops are hand hoed or cultivated with tines mounted to a
      two-wheeled tractor to provide the seed bed for the green manure seeds. The
      crops are then undersown with the grower holding a container in their hands.

      The advantage of broadcasting is speed. The disadvantage is inaccuracy with
      possible patchy areas of green manure. Also with crops like cabbages and
      cauliflowers, green manure seeds may germinate in their hearts.


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