دانلود رایگان مقاله خوابیدگی محصول ناشی از باد و باران

Abstract

A methodology to estimate wind and rain effects on the four main growth crops in the United Kingdom is presented. The method is based on simulated weather scenarios acting on synthetic plants over a period of thirty years. The environmental data is generated with the UKCP09 Weather Generator considering future climate scenarios whereas plants are modelled as simple oscillators characterised by their mass, stiffness and damping. The joint probability of occurrence of wind and rain are estimated together with the conditions in which lodging would occur. The paper shows that the dynamic response of plants varies with season being the first three months of the year the most critical whilst the plants’ performances define crop failure velocities ranging between 4 ms−1 and 23 ms−1 and associated failure rates of 50% and 5% per unitary velocity.

9. Final remarks

The paper has shown a method to estimate crop failure by using statistical descriptions of the climate such as those provided by the UKCP09 Weather Generator together an existing theoretical model to calculate the plant’s response. The weather scenarios studied cover a horizon of 30 years. The data predicts an increase of wind velocities of about 4.5% with respect to current conditions. The weather predictions also suggest that the level of rain that is exceeded 50% of the time will range between 1.75 mm during April and 2.75 mm in November. That makes a yearly average of 2.25 mm i.e. slightly above the current reference value of 2 mm. Regarding the crop responses, the study identifies oats as the most resilient type of plantfrom the group whilst rapeseed appears to be the most susceptible to fail. For example the failure velocity for 100% of the oat crop is estimated as of 23 ms−1 and it is of 4 ms−1 for rapeseed, for a level of rain that is exceeded 50% of the time. The prediction model also indicates that the failure velocity will become constant after a threshold value of rain (that is exceeded 50% of the time) in the region of 7.5 mm i.e. stem failure would dominate the plant’s failure after that point. Finally,the proposed research methodology suggests three areas of development:(a)the interaction of plants in motion and with the changes caused in the boundary layer during that process, (b) the availability correlated wind and rain statistics, and (c) development of finite element models that enable to observe the flow of stress and rate of deformation experienced by different segments of plants at the time that allow quantifying lodging i.e. modelling large populations of plants at high resolution.