16th IFOAM Organic World Congress, Modena, Italy, June 16-20, 2008
Archived at http://orgprints.org/view/projects/conference.html
QLIF Workshop 3: Performance of Organic and Low Input Crop
Production Systems1
Ulrich Köpke2, Julia Cooper3, Hanne Lindhard Petersen4, Geert J. H. M. van der Burgt5
and Lucius Tamm6
Key words: crop yield, wheat productivity, potato productivity, intensive agriculture,
conventional agriculture, ecosystem services
Abstract
Yields in organic and low input production systems tend to be lower than those
obtained in intensive conventional systems. To narrow the productivity differences a
range of challenges associated with organic and other ‘low input’ systems have been
identified. These include the need to (a) develop improved organic matter-based soil
management and fertilisation protocols, (b) address key crop protection challenges via
improved management, variety selection, and alternative treatment approaches and
(c) address food safety concerns raised about organic and low input production. QLIF
workshop 4 will summarise results from the crop production focused subproject (SP3)
of the QualityLowInputFood IP. This paper summarises crop productivity focused QLIF
results from SP3 (and to a lesser extent SP2) in the context of current scientific
knowledge.
Introduction
Compared with intensive mainstream agriculture, marketable yields per hectare of
most field crops of organic agriculture systems under conditions of European
temperate climate are generally lower (Tab.1).
Table 1: Yields of field crops produced in central European temperate climates
relative to conventional reference yields (rel.=100) (Offermann and Nieberg 2000,
Niggli et al., 2007)
Crop
Wheat
Barley
Oats
Grain maize
Oilseeds
Potatoes
Pulses
1
DE
58-63
62-68
70
60-67
54-69
49-73
AT
62-67
58-70
56-75
78-88
39-54
83-85
Countryz
CH
64-75
65-84
73-94
85-88
83
62-68
88
FR
44-55
70-80
66-80
67-80
68-79
83
IT
78-98
55-94
88
55-93
48-50
62-99
73-100
The full version of this paper is archived at http://www.orgprints.org/13378
2
Institute of Organic Farming (IOL), University of Bonn, Bonn, Germany. Please contact:
ukiol@uni-bonn.de.
3
Nafferton Ecological Farming Group (NEFG), Newcastle University, Stocksfield, NE42 7XD, UK.
4
University of Aarhus, Aarhus, Denmark
5
Louis Bolk Instituut, Driebergen, The Netherlands
6
Research Institute of Organic Agriculture (FiBL), Ackerstrasse, CH-5070 Frick, Switzerland
16th IFOAM Organic World Congress, Modena, Italy, June 16-20, 2008
Archived at http://orgprints.org/view/projects/conference.html
z
DE=Germany; AT=Austria; CH=Switzerland; FR=France; IT=Italy
Clearly improvements in yield need to be a major target under organic and low input
production systems in the context of an increasing world population, predicted
reductions in the global land area available for agricultural production due to climate
change and increasing use of crops as animal feeds and for energy production.
The aims of workshop 3 are therefore:
1.
2.
3.
To identify productivity limiting factors in organic and low input systems in
comparison with intensive agriculture.
To measure the impact of the QLIF project on the yields of organic and low input
systems.
To discuss further approaches to increase productivity and yield stability of
organic and low input systems.
Output and contribution of the QLIF project to the state-of-the-art
Effect of crop management practices on yield of wheat
A recent review of the literature on conventional and organic management systems for
wheat identified soil nutrient deficiencies (especially phosphorus and nitrogen) and
competition from weeds, as the main reasons for lower yields in organic grain
production. (Mason and Spaner, 2006). Declining soil fertility under organically grown
wheat has also been reported, with P levels often deficient, especially at sites
managed organically for 30 to 70 years (Entz et al., 2001). Reduced yields in organic
and low-input production may also be caused by a higher incidence of certain
diseases. For example, Poveda et al. (2006) reported higher incidences of Septoria in
organically managed wheat than conventional wheat. Studies under WP2.1.1 of QLIF
showed that foliar Septoria disease is the only yield limiting disease in organic
production systems, while other diseases such as mildew and lodging only had a
negative effect on yield in conventional systems (Leifert et al. unpublished). Studies
under WP3.5.4 of QLIF indicate that two of the main problems relating to the
sustainability of the current organic wheat production methods (lower yields and
protein contents) can be addressed by changes in cultivar choice, fertility
management and pre-crop management practices (Wilkinson et al. 2007).
Effect of crop management practices on yield of potato
Previous studies (e.g. those carried out as part of the EU FP5 Blight-MOP project
showed that (a) potato blight is a major factor affecting yields and (b) the impact of the
disease on yield can be significantly reduced by improved variety choice and
management practices (e.g. Speiser et al. 2006). However, even in years with low
blight incidence yields in organic production often remain 30-40% lower than those in
intensive conventional production. Studies under WP2.1.2 of QLIF showed that
productivity and the differential in yield between organically and conventionally
managed plots increased from approx 30% in years 1 and 2 after conversion to 50%
four years after conversion. Thus, insufficient supply of macro-nutrients is a further
reason identified for lower yields in organic potato. Potato have very shallow root
systems and are associated with high nutrient (N, P and K) losses. The development
of (i.) more N and P-efficient potato cultivars and (ii.) organic matter based fertilisation
regimes that improve nutrient supply (especially N) at key development stages of
potato (e.g. tuber initiation) are therefore thought to be the main approaches to
increase potato yields in organic and ‘low input’ systems.
16th IFOAM Organic World Congress, Modena, Italy, June 16-20, 2008
Archived at http://orgprints.org/view/projects/conference.html
Effect of crop management practices on yield of field vegetable crops
Yield differentials between conventional and organic/‘low input’ vary significantly
among different vegetables. Studies under WP2.1 of QLIF showed significantly lower
(usually between 20-40%) yields for cabbage (linked to fertility management
practices), while yields for organic onion and lettuce were similar or only slightly
reduced (10-20%) compared to conventional crops. In cabbage protective netting was
significantly more efficient than pesticides for controlling cabbage root flies and
resulted in an increase in yield in organic systems. Also, in lettuce the higher
Sclerotinia incidence in conventional crops (associated with the use of mineral
fertilisers) resulted in a reduction in marketable yield. Improvements in field vegetable
crops should therefore focus on improving fertilisation protocols that do not
simultaneously exacerbate problems from crop pests and diseases.
Conclusions
Crop productivity in organic and low input systems is based on key pillars, i.e.
1.
2.
3.
4.
5.
a fertile soil which provides sufficient capacity to allow for plant growth while
preventing soil-borne diseases,
high quality, disease-free seeds and plant material,
a crop-specific soil fertility management plan to provide sufficient nutrients for
optimum plant growth,
adequate varieties/cultivars,
crop protection techniques to prevent damage due to noxious organisms (Tamm
et al., 2007).
The QLIF project has developed improved component strategies to overcome
technological bottlenecks in annual (wheat, lettuce, tomato) and perennial (apple,
results not discussed here) crop production systems further. Improvements in
productivity were very clearly shown to be possible under the precondition of:
-
favourable soil structure and soil chemical fertility as well as weather conditions
high availability of nutrients (especially N and P), due to high amounts of soilborne as well as added nitrogen.
More than in any other production systems the term ‘productivity’ in Organic
Agriculture is strongly related to product quality, an overall aim of Organic Agriculture
from the beginning. Thus, the term productivity in Organic Agriculture per se includes
the production of a marketable yield of highest quality and therefore contrasts with the
traditional term of productivity measured in yields or Megajoule output per hectare,
only.
Lower per se productivity opens niches for higher product quality and ecological
services and benefits (Brandt and Møldgaard 2001; Cooper et al. 2007). For example
1.
2.
3.
Lower nitrogen inputs can potentially reduce N leaching, thus, resulting in higher
groundwater quality
Lower density of cereal stands resulting from lower N availability may cause
higher density of wild flora and endangered wild plants.
As a function of planned (crop rotation) and associated biodiversity in crops and
wild plants, favourable habitats for insects, soil microbes, and wild and
endangered animals are provided. Thus, Organic Agriculture offers benefits by
on-site nature conservation.
16th IFOAM Organic World Congress, Modena, Italy, June 16-20, 2008
Archived at http://orgprints.org/view/projects/conference.html
4.
Since lower productivity generally results in conditions enabling a multifunctional
agriculture approach (i.e. the provision of ecosystem services), we strongly
discourage using the words ‘productivity gap of organic and low input systems in
comparison with intensive agriculture’, because this suggests a shortcoming of
Organic Agriculture needing correction. The overall aim is system optimisation in
the framework of Organic Agriculture’s multifunctional approach, rather than
realising yields equivalent to conventional farming at the expense of the
environmental services provided by Organic Agriculture.
Acknowledgments
The authors gratefully acknowledge funding from the European Community financial
participation under the Sixth Framework Programme for Research, Technological
Development and Demonstration Activities, for the Integrated Project
QUALITYLOWINPUTFOOD,FP6-FOOD-CT-2003- 506358.
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