THE GOLDEN HOOF AND GREEN MANURE - MEAT: A Benign Extravagance - page 96

3:1 Pre-industrial China: Shen's Agricultural Book , a 17th-century Chinese manual describes a system
where one third of a hectare of milk-vetch provides 7500 kg of green manure for a hectare of the following
irrigated rice crop - this level of only 25 per cent green manure may be achievable because irrigated rice
usually obtains some of its nutrients through the application of large amounts of water. 10
3:1 Elm Farm: three four year rotations with one year's red clover: clover, winter wheat, winter wheat
spring oats; clover, potatoes, winter wheat, winter oats; and clover, winter wheat, winter beans, winter
wheat. This experiment has been continued for 15 years, and average crop yields have been maintained with
no apparent nutrient loss. However phosphate has been added and a number of problems have been experi-
enced including a decline in organic matter and mycorrhizal activity in the soil and a build up of perennial
weeds.
4:1 Norway: oats, red clover, oats, spring wheat, barley. This rotation did not accumulate enough N to
compensate for the N removed in cereals. 11
4:1 Terrington: 5 year rotation of clover, potatoes, winter wheat, beans and spring wheat. On grade 1
land, high yields for grain. It started out with two courses of red clover, so over the first 15 years there were
three years of clover. Phosphorus added. Problems with establishing clover. 12
5:0 Rodale, PA USA: A five year five crop rotation of corn, soybeans, oats, corn oats. After 1991 this
was changed to a three year rotation of corn, soybean and wheat. 13
1 Rodale Institute (2000), Crop Rotation Basics: How to Zap Pests, Build Soil with Cover Crops in Strategic
Crop Rotations , p 3, http://www.rodaleinstitute.org/20021001/crop_rotate
2 Abrams-McHenry, M (n.d.), 'Fertility and Land Utilization', Vohan News International , 2.
3 . Personal communication from S Oxbrow.
4 Irish Farmer's Journal (1999), Producing Organic Grain and Beef, http://www.farmersjournal.ie/1999/0821/
environment/news.html
5 Canadian Organic Growers (n.d.), A Farmer's Profile: Organic Crop Rotations, www.cog.ca/gain-

ingground_FarmerProfile.htm
6 'Tolhurst Organic Produce: A Step into the Future' (n.d.), Growing Green International , No 7.
7 Jenny Hall (n.d.), 'To Till or Not to Till', Growing Green International , No 7.
8 Thorup-Kristensen, K (2005), U s e of Green Manure, Catch Crops and Deep Rooted Crops in an Organic
Vegetable Rotation , Danish Institute of Agricultural Sciences, Dept of Horticulture.
9 CWS Farm Groups (2002), Organic Farming: Experiments 1989-1997 - A Summary of Key Findings , ht-
tp://www.pmac.net/focus_on_practice.html
10 Zhang Luziang (1956), op cit. in Netting, op cit. , p 137.
11 Løes, A K et al (2007), N Supply in Stockless Organic Cereal Production under Northern Temperature
Conditions. Undersown Legumes, or Whole Season Green Manure?, 3rd QLIF Conference, Hohenheim, Germany
20 March 2007, www:orgprints.org/9823/
12 DEFRA, 2002, Testing the Sustainability of Stockless Arable Organic Farming on a Fertile Soil, OF0301 ,
Final Report 2002.