Agricultural Economics

Factors determining the efficiency of organic farming systems



Scientific coordination: Prof. Dr. Uwe Latacz-Lohmann

A rising number of farmers consider organic agriculture a financially attractive alternative to conventional farming systems. However, within the group of organic farms vast differences exist among farms in profitability and efficiency. This subproject sets out to answer the following questions: 1. How big are the differences in efficiency among organic farms? 2. Is their a link between profitability and technical efficiency? 3. What are the potential savings in inputs on inefficient holdings? 4. Which factors determine profitability and technical efficiency of organic farm holdings? Findings from this subproject should be of interest to farm consultants and policy makers as well as to farmers who consider converting their holdings to organic agriculture. A thorough assessment of the prospects for financially sustainable conversions can contribute to preventing unsuccessful conversions.



Optimisation of organic crop rotations

(2001-10-01- 2039-12-31)


Scientific coordination: Prof. Dr. Friedhelm Taube; Dr. Ralf Loges


Nitrogen as a nutritive element is of high importance for yield formation of agricultural crops. Due to the ban on synthetic chemical N-fertilizers in organic agriculture the cultivation of high N-demanding crops is difficult. Hof Ritzerau’s subproject Agronomy is testing four strategies to improve N-supply and N-efficiency of organic farming systems: 1. Optimisation of N-fluxes in organic crop rotations through variation of the percentage of N2-fixing legume crops in the crop rotation 2. Improvement of green manure and grass-clover management with special regard to the option of winter grazing. 3. Optimisation of N-supply of organic grown cereals through site-specific application of organic manure 4. Development of a minimum tillage cereal cropping system for organic farming: "Bi-cropping" of cereals and N2-fixing white clover.



Monitoring amphibian-populations in their breeding waters and terrestrial habitats

(2002-04-01 - 2039-12-31)


Scientific coordination: Prof. Dr. Hartmut Roweck


Monitoring amphibian-populations in their breeding waters and terrestrial habitats. The aim is to study the effects of ecological farming on amphibians and their habitats. Therefore the reproducing species their spawn, larva and juveniles are counted at the breeding waters of Hof Ritzerau by semi-quantitative methods. To get information on terrestrial habitats, the amphibians captured in pitfalls of the current ground beetles study and in future also nightly observations of amphibians along transects are analysed. The focus here is primarily on arable land and field margins.



(2001-05-01 - 2039-12-31)


Scientific coordination: Prof. Dr. Ulrich Irmler


The aim of the investigation is the analysis of the changes in the beetle community, corresponding to the conversion from conventional to organic farming. Ground-beetles (Carabidae) and rove-beetles (Staphylinidae) have been selected as representative insects to study species richness during the conversion. 168 pitfall traps have been installed in the study area, this included 140 pitfall traps on the arable fields and 28 in the hedgerows, close to ponds or in fallows. Sampling period started in May 2001, interrupted by harvest and soil cultivation only. The main questions are: - How are the species on the farmland spatially distributed? - Do species benefit from the conversion to organic farming? - How do different crops, the distance to field boundaries or the adjacent biotopes effected the number of species and species richness?


Breeding birds

breeding birds and changing farming conditions

(2001-04-01 -2039-12-31)


Scientific coordination: Prof. Dr. Hartmut Roweck


In this Project the avian community in farmland is investigated under different cultivation methods. Most new studies about farmland birds describe a large overall decline of these species under conventionell farming methods but there are no clear reasons the the decline. Since 2001the bird community has been mapped every year. After one year with conventional farming with predominating winter cereals two periods of conversion followed and since 2004 farming is carried out under organic methods. First results indicate coherence between breeding density of farmland birds and the quality of the vegetation, especially time of growing, hight and density.



Nature-orientated forest edges as habitats for butterflies and moths

(2003-05-01 - 2039-12-31)


Scientific coordination: Prof. Dr. Hartmut Roweck


The habitat quality of different from human impact influenced forest edges for butterflies and moths is investigated. For this purpose a comparison of the larvae occurring on trees and bushes is made. In addition two light-traps are continuously operated to get an overview about all kind of Lepidoptera in this area. The aim is to detect influences of cattle-grazing in wood pastures, starting in 2006. The results should help to optimise forest edges in agricultural landscapes as habitats for butterflies and moths.



Spatial and temporal dynamics during the change to organic managment on arable fields

(2001-05-01 - 2039-12-31)


Scientific coordination: Prof. Dr. Ulrich Irmler


Earthworms are one of the most important animal group in nutrient turnover and water regulation of soils. Within the project, earthworms are sampled since the year 2001 in monthly intervals at a grid of 85 sites from April to June and September to November. On average 10 species were recorded with a mean density of 92 ind./m² and 5 g ash free biomass/m². The spatial and temporal distribution of density and biomass depended on climate and change of management from conventional to organic agriculture. The density of Lumbricus terrestris increased on organically managed fields, whereas L. rubellus was positively correlated with rainfall. In the dry year 2003 a breakdown of the earthworm population was observed, in the wet year 2002 waterlogged sites in spring were characterised by low densities of earthworms that regenerated not until the 2nd year. In total, the bioturbation by earthworms was estimated between 24 and 50 t/ha on the agricultural fields.



Ecohydrology and vegetation of the areas with high groundater level

(2001-06-01 - 2039-12-31)


Scientific coordination: Prof. Dr. Joachim Schrautzer


The changes in hydrology, hydrochemistry and vegetation occurring along with conversion to organic farming and re-wetting of the fen “Duvenseebachniederung” are observed by a monitoring program. The scientific focus is on the functional role of surface waters and wetlands as well as their interactions in the nutrient cycle of agricultural lowland catchments. We calculate nutrient budgets for a small nutrient-rich stream, the “Duvenseebach”, on the basis of automated daily sampling. The study of retention dynamics and forcing functions of nutrient processes aim at deriving seasonal and event-related retention coefficients. An hourly resolution of water levels, temperature, pH, electrical conductivity and oxygen concentration allows detailed investigation of different diel and seasonal patterns of the hydrological and biogeochemical processes in the stream.


Environmental Education

Holistic learning within the domain of ecological farming

(2004-06-01 - 2009-12-31)


Scientific coordination: Prof. Dr. Hartmut Roweck


This subproject informs about the research at Hof Ritzerau and communicates general matters of environmental education. Main focus is put on generally understandable and illustrated description so the concerns and aims of eco-farming can also be understood without previous knowledge. Several posters concerning this item have been designed; in an additional project an eco-farming learning path´s concept is now going to be developed. Appealing and plain stations offering experience are meant to explain the grange´s and the cultivation´s characteristics, to arouse interest and sympathy for eco-farming and to make a contribution to education for sustainable development.


Landscape Ecology

Structural an functional analysis of abiotic landscape elements


(2001-03-01 - 2039-12-31)


Scientific coordination: Prof. Dr. Hartmut Roweck


The consequences of changes in landuse are estimated on a regional scale by the means of a sample of methods named DILAMO (Digital Landscape Modelling). The simulation program WASMOD is used for balancing fluxes of water and substances in a high temporal and spacial resolution. The system AIS is developed to show important variables and processes in the balance of water, carbon and nutrients in a high temporal resolution. By this means it is possible to analyse the heterogeneous effects of measures used in plant production and adapt them to smaller scales. Because "Hof Ritzerau" is a long-term project with many staff members we develope a method for long-term data storage with integrated storing of metadata. A huge fraction of all spatial data of the project is presented via a mapserver.




(2002-03-01 - 2039-12-31)


Scientific coordination: Prof. Dr. Stefan Vidal


In a long term monitoring this research project will document the changes in abundance of pests related to the swift from conventional to ecological farming practice. Special emphasis is given to the tritrophic interactions of cultivated plant (winterwheat), cereal aphids and their natural enemies, especially to the parasitoids. The ecological crop rotation systems differ in their percentage of legumes and were compared with conventional treated fields nearby with high input of nitrogen fertilisers. Another focuse of this project concerns the pea weevil Sitona lineatus, an important pest species of grain legumes. Most of the damage to the plants results from larval feeding on the roots and root nodules, reducing nitrogen fixation and thereby the nitrogen-supply in the soil for a subsequent wheat crop.


Soil Sciences


(2001-03-01 - 2006-08-31)


Scientific coordination: Prof. Dr. Hans-Rudolf Bork


The distribution, the properties and the development of the soils near Hof Ritzerau are investigated in detail. During Neolithic Age people started to clear the woodland which had developed during early Holocene. The cleared land was then used agriculturally. During Bronze Age and Iron Age agricultural land use was intensified. Soil erosion and sedimentation changed the distribution and the properties of the soils during prehistoric times significantly. Succession and woodland were dominating in the migration period. Agriculture was common during early and high Medieval Times. The intensification of land use during the late 19th and the 20th centuries enabled high rates of soil erosion on slopes and the development of agricultural terraces at the rim of the valley of the Duvenseebach. With the recent introduction of organic farming a period of successful soil conservation began.


Floristic Diversity


(2001-03-01 - 2039-12-31)


Scientific coordination: Prof. Dr. Hartmut Roweck



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