Organic open field cultivation in the Netherlands

The arable farming and field vegetable cultivation sector is a significant part of the organic agricultural sector in the Netherlands. The sector produces not only vegetables for human consumption, but also organic animal feed such as maize an cereals. To facilitate organic farmers, Wageningen UR and Louis Bolk Institute carry out a variety or research aimed specifically at organic arable farming and field vegetable production. The report contains sector facts, sector aspirations, current affairs and research projects

A method to search for optimal field allocations of transgenic maize in the context of co-existence

Spatially isolating genetically modified (GM) maize fields from non-GM maize fields is a robust on-farm measure to keep the adventitious presence of GM material in the harvest of neighboring fields due to cross-fertilizations below the European labeling threshold of 0.9%. However, the implementation of mandatory and rigid isolation perimeters can affect the farmers' freedom of choice to grow GM maize on their fields if neighboring farmers do not concur with their respective cropping intentions and crop plans. To minimize the presence of non-GM maize within isolation perimeters implemented around GM maize fields, a method was developed for optimally allocating GM maize to a particular set of fields. Using a Geographic Information System dataset and Monte Carlo analyses, three scenarios were tested in a maize cultivation area with a low maize share in Flanders (Belgium). It was assumed that some farmers would act in collaboration by sharing the allocation of all their arable land for the cultivation of GM maize. From the large number of possible allocations of GM maize to any field of the shared pool of arable land, the best field combinations were selected. Compared to a random allocation of GM maize, the best field combinations made it possible to reduce spatial co-existence problems, since at least two times less non-GM maize fields and their corresponding farmers occurred within the implemented isolation perimeters. In the selected field sets, the mean field size was always larger than the mean field size of the common pool of arable land. These preliminary data confirm that the optimal allocation of GM maize over the landscape might theoretically be a valuable option to facilitate the implementation of rigid isolation perimeters imposed by law.

The arable farmer as the assessor of within-field soil variation

Feasible, fast and reliable methods of mapping within-field variation are required for precision agriculture. Within precision agriculture research much emphasis has been put on technology, whereas the knowledge that farmers have and ways to explore it have received little attention. This research characterizes and examines the spatial knowledge arable farmers have of their fields and explores whether it is a suitable starting point to map the within-field variation of soil properties. A case study was performed in the Hoeksche Waard, the Netherlands, at four arable farms. A combination of semi-structured interviews and fieldwork was used to map spatially explicit knowledge of within-field variation. At each farm, a field was divided into internally homogeneous units as directed by the farmer, the soil of the units was sampled and the data were analysed statistically. The results show that the farmers have considerable spatial knowledge of their fields. Furthermore, they apply this knowledge intuitively during various field management activities such as fertilizer application, soil tillage and herbicide application. The sample data on soil organic matter content, clay content and fertility show that in general the farmers’ knowledge formed a suitable starting point for mapping within-field variation in the soil. Therefore, it should also be considered as an important information source for highly automated precision agriculture systems

Effect of sieving on ex-situ soil respiration of soils from three land use types

This study aims to investigate the effect of sieving on ex situ soil respiration (CO2 flux) measurements from different land use types. We collected soils (0–10 cm) from arable, grassland and woodland sites, allocated them to either sieved (4-mm mesh, freshly sieved) or intact core treatments and incubated them in gas-tight jars for 40 days at 10 °C. Headspace gas was collected on days 1, 3, 17, 24, 31 and 38 and CO2 analysed. Our results showed that sieving (4 mm) did not significantly influence soil respiration measurements, probably because micro aggregates (< 0.25 mm) remain intact after sieving. However, soils collected from grassland soil released more CO2 compared with those collected from woodland and arable soils, irrespective of sieving treatments. The higher CO2 from grassland soil compared with woodland and arable soils was attributed to the differences in the water holding capacity and the quantity and stoichiometry of the organic matter between the three soils. We conclude that soils sieved prior to ex situ respiration experiments provide realistic respiration measurements. This finding lends support to soil scientists planning a sampling strategy that better represents the inhomogeneity of field conditions by pooling, homogenising and sieving samples, without fear of obtaining unrepresentative CO2 flux measurements caused by the disruption of soil architecture

Use of rare earth oxides as tracers to identify sediment source areas for agricultural hillslopes

Understanding sediment sources is essential to enable more effective targeting of in-field mitigation approaches to reduce diffuse pollution from agricultural land. In this paper we report on the application of rare earth element oxides to arable soils at hillslope scale in order to determine sediment source areas and their relative importance, using a non-intrusive method of surface spraying. Runoff, sediments and rare earth elements lost from four arable hillslope lengths at a site in the UK with clay soils were monitored from three rainfall events after tracer application. Measured erosion rates were low, reflecting the typical event conditions occurring at the site, and less than 1% of the applied REO tracers were recovered, which is consistent with the results of comparable studies. Tracer recovery at the base of the hillslope was able to indicate the relative importance of different hillslope sediment source areas, which were found to be consistent between events. The principal source of eroded sediments was the upslope area, implying that the wheel tracks were principally conduits for sediment transport, and not highly active sites of erosion. Mitigation treatments for sediment losses from arable hillslopes should therefore focus on methodologies for trapping mobile sediments within wheel track areas through increasing surface roughness or reducing the connectivity of sediment transport processes

Functional agro biodiversity in Dutch arable farming: results of a three year pilot

A pilot on 400 ha of Dutch arable farms during 2004-2007 perennial grassy field margins and functional annual flower strips were created on potato and wheat fields. Monitoring information on pests and natural enemies was directly communicated to the farmers to support pest management decisions. Due to the increasing numbers of natural enemies and the gradually reducing peak densities of aphids, the farmers could refrain from insecticide applications against aphids in these crops. The pilot has yielded great public awareness on possibilities for functional agro biodiversity in arable crops

Barriers for developing more robust organic arable farming systems in practice

There is a gap between the scientific idea of robust and economically viable organic arable farming systems with optimized crop rotations for nutrient and pest management and how these systems look like in practice. In order to explore this gap, we visited and interviewed ten organic arable farms in Denmark. Our main findings are: 1) Organic arable farming operates in a very dynamic and changing environment in terms of prizing and market opportunities, and the main focus of the farm managements was the coping strategy within this changing environment; 2) The farming systems were continuously changing and developing, buying and renting more land, changing manure agreements and other forms of cooperation and arrangements; 3) Short term profit was paid much more attention than more theoretical expectation on long term profit or opportunities in relation to optimizing the production system. This again seems logical in relation to the very dynamic world that the farmers have to operate within; 4) Most of the farmers do not see their farm as a coherent system but as a coordination of a series of separate operations, which means that most decisions are taken with specific reference to the individual field in at the present situation without considering the long-term effects. Management focus is thus much more on solving problems as they are occurring, by adjusting their practice, than it is on developing a robust system preventing problems to occur. This partial focus is also strongly supported by the way in which extension services mostly operate

Prevention and control of weeds, pests and diseases

Weed control still requires major investments of money and labour in organic arable farming and field vegetable cultivation. For this reason, current research is focused to a large extent on the development of weed control strategies. These incorporate prevention as well as mechanical methods, and cover a range of approaches. From inexpensive techniques to very innovative technologies. Research into pests and diseases primarily focuses on improving systems and preventing infestation. However, even with maximum prevention measures some pests and diseases still cause unacceptable damage. For these residual problems control measures are being develope

The soil quality concept and its importance in the study of Finnish arable soils

Arable soil is a functional unit whose condition is vital to crop production, but also to ecosystems at large owing to the significant role of soil in global nutrient cycles and balances. The soil quality concept recognises the concern for the sustainability of current arable land use practices. It integrates soil chemical, physical and biological properties, and takes account of the interaction of soil with water and air. This paper reviews the soil quality concept and its applications and discusses the importance of the concept for the assessment of Finnish arable soils. Many aspects of the chemical quality of arable soil are already well known in Finland. In contrast, follow-up of the physical and biological soil components, which are increasingly seen as important features of soil quality, is rudimentary. For monitoring of the soil quality at different scales – field, regional, national and global – a suitable set of indicators needs to be identified. In this paper particular attention is paid to the potential importance and usefulness of selected biological indicators. It is clear that more basic research is needed to provide scientists and advisors with a solid basis for transmitting reliable information on soil quality. While the soil quality concept has been justifiably criticised, it has clear merits in the integrated handling of the soil entity and in highlighting the environmental aspects of arable soil quality