Wrapping function to run maize model on several site-years
maize.multisy(param, list_site_year, sdate, ldate,
weather_all = weather_EuropeEU)
: a vector of parameters
: vector of site-year
: sowing date
: last date
: weather data.frame for corresponding site-years
a data.frame with simulation for all site-years, with the first column sy indicating the site-years