Application to landuse aspects

In order to assess the potential for pea production in Europe, the model was applied to a range of European conditions for pea crops, based on parameters for the standard cultivar 'Solara', which has been used in other PROFETAS projects. Since nitrogen is usually not a limiting factor for peas, the model was run with three water supply scenarios: supply as crop demand versus 200 mm and 100 mm initial soil available water. These three water supply scenarios represent pea cultivation with ample water supply (i.e. irrigation), pea cultivation on loamy clay soil without irrigation, and pea cultivation on sandy soil without irrigation, respectively. Simulations used climate data (1991-2000) from the Environment

Humidity Daylength Radiation

Wind Temperature CO2

Humidity Daylength Radiation

Wind Temperature CO2

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Soil water

Soil N

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Soil water

Soil N

Figure 10.3 The relational diagram of the GECROS crop growth model and Sustainability Institute of the European Commission for 66 pre-selected locations in Europe. Using GIS, the 10-year average seed yields were mapped for all three water supply scenarios (Figure 10.4).

Not surprisingly, predicted crop productivity depends strongly on water supply for all sites. Annual variability in predicted crop productivity was greater under water-limited conditions than under non-limiting conditions. Areas with potentially high predicted productivity, such as Scotland, Denmark, North Germany, and part of France are, indeed, regions in Europe where peas are currently grown. The Netherlands seems to be well suited for growing peas. The higher productivity in North Western Europe and South Scandinavia compared to Southern Europe was basically due to a longer crop growing period as a result of a cooler environment. However, caution should be taken, since the simulations were done without considering geographic information on soil quality and landscape. Furthermore, the simulation concerned only 66 sites, and in some areas (such as Scandinavia) mapping was merely the result of extrapolating just a few points. Therefore, improved simulations should incorporate local specific soil and landscape information and more locations.

In actual practice, pea performance appears to be sensitive to excess water or drought during flowering and harvesting. Peas easily lodge in heavy rains, presenting a major risk for harvesting (lodged crops remain wet for longer, are susceptible to fungal attack, whereas combine harvesters have difficulty reaping plants that are lying flat on the soil surface). Improved straw stiffness has been a major focus in pea breeding. The effect of drought and lodging severity in reducing canopy photosynthesis and seed set can be well assessed by GECROS.

Figure 10.4 Map of pea seed yields under three water supply scenarios (decreasing from left to right, see the text) from interpolation of point model simulation for 66 sites

However, it has been beyond the reach of the current project to rigorously quantify the effect of excess water and lodging incidences per se, because of a lack of data. Soil-borne fungal diseases are a second practical problem of pea. Root rot diseases, in particular 'near wilt', caused by the fungus Fusarium oxysporum needs to be mentioned. Since no cure exists, prevention is the only measure that can be taken. The best prevention is to grow a crop of peas on a field only once every six years. In summary, the validated model could be a powerful tool in:

• predicting responses of global environmental change on crop production and cropping systems;

• defining crop ideotypes adapted to a target environment;

• optimising management strategies for specific crop genotype and environment; and

• designing sustainable cropping systems.

If the model is linked to a GIS environment, it can be used for studies on land use, greenhouse gas emissions and water (precipitation) requirements, while providing valuable suggestions for geographic location and fine-tuning in order to optimise sustainable production of crops.

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