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Suomi P.,National Resources Institute Finland Luke | Oksanen T.,Aalto University
Computers and Electronics in Agriculture | Year: 2015

Typical sowing depth for cereal crops is in range of 20-50. mm, depending on the soil type and crop. The variation in the sowing depth causes variation in germination and the seeds placed too deep are not sprouting. To compensate the spatial variation in soil type and conditions, an automatic depth control for a seed drill was developed. The seed drill used in this study was equipped with the wedge-roller type single-disc coulters that help in the working depth regulation but an electronic system is necessary on top of that. The developed electronic control system was compatible with ISO 11783 communication standard. The working depth was measured by using multiple sensors. The control system utilises ISO 11783 remote control messages to command the auxiliary valves of the tractor over ISO 11783 on the implement side. The system was tested on the field, at first to validate the measurement system and later to test the ability of the control system to adjust the working depth. The control system was able to maintain the desired working depth within tolerance ±10. mm at driving speed 10. km/h. The true samples of sowing depth were compared with working depth estimate in the same spot and it was found that the sowing depth was 1.7. mm shallower compared with the working depth on average. © 2015 Elsevier B.V. Source


Tao F.,Natural Resources Institute Finland Luke | Rotter R.P.,Natural Resources Institute Finland Luke | Palosuo T.,Natural Resources Institute Finland Luke | Hohn J.,Natural Resources Institute Finland Luke | And 3 more authors.
Climate Research | Year: 2015

We adapted a large area crop model, MCWLA-Wheat, to winter wheat Triticum aestivum L. and spring wheat in Finland. We then applied Bayesian probability inversion and a Markov Chain Monte Carlo technique to analyze uncertainties in parameter estimations and to optimize parameters. Finally, a super-ensemble-based probabilistic projection system was updated and applied to project the effects of climate change on wheat productivity and water use in Finland. The system used 6 climate scenarios and 20 sets of crop model parameters. We projected spatiotemporal changes of wheat productivity and water use due to climate change/variability during 2021-2040, 2041-2070, and 2071-2100. The results indicate that with a high probability wheat yields will increase substantially in Finland under the tested climate change scenarios, and spring wheat can benefit more from climate change than winter wheat. Nevertheless, in some areas of southern Finland, wheat production will face increasing risk of high temperature and drought, which can offset the benefits of climate change on wheat yield, resulting in an increase in yield variability and about 30% probability of yield decrease for spring wheat. Compared with spring wheat, the development, photosynthesis, and consequently yield will be much less enhanced for winter wheat, which, together with the risk of extreme weather, will result in an up to 56% probability of yield decrease in eastern parts of Finland. Our study explicitly para - meterized the effects of extreme temperature and drought stress on wheat yields, and accounted for a wide range of wheat cultivars with contrasting phenological characteristics and thermal requirements. © Inter-Research 2015. Source

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