N, P and K on organic farms: herbage and cereal production, purchases and sales

Fowler, Susan; Watson, Christine; Wilman, D.

doi:10.1017/s0021859600076516

Cited by 16 publications

(4 citation statements)

References 7 publications

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“…The founding of the journal Biological Agriculture and Horticulture in 1982 and the American Journal of Alternative Agriculture (now Renewable Agriculture and Food Systems ) in 1986 were landmarks in the publication of scientific information relating to organic agriculture. Publication of organic farming research in mainstream journals was rare before the late 1980s and early 1990s (Watson & Atkinson 2002); for example, the first publication in the Journal of Agricultural Science, Cambridge was in 1993 (Fowler et al 1993). The history of organic research in 11 European countries is described in Lange et al (2006).…”

Section: Drivers Of the Organic Research Agendamentioning

confidence: 99%

Research in organic production systems – past, present and future

Watson¹,

Walker²,

Stockdale

2007

J. Agric. Sci.

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SU MMARYA large body of published research now exists on economic, social, technical and policy related aspects of organic production. The dramatic increase in published research over the last 20 years reflects not only the existence of policy support for organic farming in some countries but also the availability of government funding for research on organic farming. This has resulted in a broadening out of organic research from privately funded, specifically organic research organizations, into universities and mainstream research institutes. In parallel, publication of research results from organic farming has increasingly appeared in refereed literature in addition to literature sources more available to farmers and advisors. Research scientists from Europe, North America and Australasia have all made important contributions to the peer-reviewed literature. The literature is dominated by comparisons of organic and other forms of agriculture, although in many cases these comparisons are not fully valid. Research directed specifically at organic systems is often much more valuable in developing improved production systems than comparative research. Research on organic farming embodies both holistic and reductionist research approaches. Trans-disciplinary research also has an important role to play in understanding the complexities of the ecological approach to agriculture typified by organic farming. Working within the principles and standards of organic agriculture will mean that some research will always be specific to organic production systems. However, in future an increased transfer of knowledge from organic to conventional agriculture and vice versa is envisaged.

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Section: Drivers Of the Organic Research Agendamentioning

confidence: 99%

Research in organic production systems – past, present and future

Watson¹,

Walker²,

Stockdale

2007

J. Agric. Sci.

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“…The farms have been described by Fowler et al (1993). Brynllys, in north Dyfed near the sea, is primarily a dairy farm with the Soil Association Table 3 and Fig.…”

Section: A T E R I a L S And M E T H O D Smentioning

confidence: 99%

“…On both farms substantial amounts of N were made available to plants each year by symbiotic fixation by Rhizobium and/or by buying manure (Fowler et al 1993); these greatly exceeded the amounts of N sold (Fowler et al 1993). Small exports of N in sales relative to the amounts of N applied and/or fixed are normal on holdings on which fertilizer N is used, particularly where the sales include animal products (Whitehead et al 1986).…”

Section: Introductionmentioning

confidence: 99%

Soil inorganic-N and nitrate leaching on organic farms

Watson¹,

Fowler

Wilman

1993

J. Agric. Sci.

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SUMMARYOn two organic farms, nitrate-N and ammonium-N in the surface layers of the soil of representative fields were recorded for 2 years. Nitrate-N was also determined in different soil layers down to 120 cm at the beginning, middle and end of two winters and at intervals after ploughing three fields, to seek evidence of leaching.Nitrate-N and ammonium-N were both consistently low in the surface layers of fields in ley. Nitrate-N accumulated in arable soils on some occasions when there was little or no crop uptake of N, after ploughing, and after very heavy applications of manure.There was some evidence of nitrate leaching in all five fields which were deep-sampled. In four cases, the loss by leaching appeared to be < 25 kg N/ha per winter. In the other case, in which a 4-year ley was ploughed on 5 October, the loss by leaching appeared to be c. 70 kg N/ha. Ploughing in winter, rather than early autumn, might have reduced the nitrate leached, but the drilling of the next crop might have been delayed.The nitrate concentration of water draining from recently ploughed sandy soil in Shropshire was high, but it would have been diluted by water draining from unploughed fields.

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“…The general reason for the large deviation between organic and conventional yields in these studies compared with those in the USA seems to be the limited purchase of manures/compost by organic farms in Europe and Australia. Nutrient flows to fields and farm-gate balances between organic and conventional farms have been examined to determine whether nutrient inputs in European organic systems are lower throughout (Kaffka and Koepf, 1989;Fowler et al, 1993;Nolte and Werner, 1994;Granstedt, 1995;Halberg et al, 1995;Nguyen et al, 1995;Fagerberg et al, 1996;Wieser et al, 1996). These studies clearly show that the mean input of N, a major yield-determining nutrient, was lower throughout in organic systems over a crop rotation period than in conventional systems.…”

Section: Cropping System Studies In Europe and Australiamentioning

confidence: 99%

Can Organic Crop Production Feed the World?

Kirchmann

Bergström²,

Kätterer³

et al.

Organic Crop Production – Ambitions and Limitations

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Agriculture provides the most essential service to mankind, as production of crops in sufficient amounts is necessary for food security and livelihood. This chapter examines the question of whether organic agriculture can produce enough food to meet future demand. This question relates to a moral imperative and any evaluation must therefore be based on objective scientific facts excluding ideological bias, political correctness, economic incentives or environmental opinions. The chapter begins by defining the conditions necessary for a stringent evaluation of crop yields and explains potential pitfalls. Yield data from national statistics, organic and conventional long-term experiments and comparative studies are then compiled and evaluated, followed by a discussion of the main factors behind low-yielding production. In a global perspective, the scientific literature shows that organic yields are between 25 and 50% lower than conventional yields, depending on whether the organic system has access to animal manure. The amount of manure available on organic farms is usually not sufficient to produce similar crop yields as in conventional systems and therefore green manures are commonly used. However, organic crop yields reported for rotations with green manure require correction for years without crop export from the field, which reduces average yield over the crop rotation. When organic yields are similar to those in conventional production, nutrient input through manure is usually higher than nutrient addition in conventional agriculture, but such high inputs are usually only possible through transfer of large amounts of manure from conventional to organic production. The main factors limiting organic yields are lower nutrient availability, poorer weed control and limited possibilities to improve the nutrient status of infertile soils. It is thus very likely that the rules that actually define organic agriculture, i.e. exclusive use of manures and untreated minerals, greatly limit the potential to increase yields. Our analysis of some yield-related statements repeatedly used by advocates of organic agriculture reached the following conclusions: Organic manure is a severely limited resource, unavailable in quantities sufficient for sustaining high crop yields; legumes are not a free and environmentally sound N source that can replace inorganic fertilisers throughout; and low native soil fertility cannot be overcome with local inputs and untreated minerals alone. 2Agricultural methods severely limiting crop yields are counter-productive. Lower organic yields require compensation through expansion of cropland -the alternative is famine. Combining expected population growth and projected land demand reveals that low-yielding agriculture is an unrealistic option for production of sufficient crops in the future. In addition, accelerated conversion of natural ecosystems into cropland would cause significant loss of natural habitats. Further improvement of conventional agriculture based on innovations, enhanced...

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N, P and K on organic farms: herbage and cereal production, purchases and sales

Cited by 16 publications

References 7 publications

Research in organic production systems – past, present and future

Research in organic production systems – past, present and future

Soil inorganic-N and nitrate leaching on organic farms

Can Organic Crop Production Feed the World?

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