The field experiment to determine do the changing weather condition still allow allohay drying in the field and the dynamics of dryness of three different grasses Italian ryegrass (Lolium multiflorum Lam.), meadow fescue (Festuca pratensis L.) and cocksfoot (Dactylis glomerata L.) in the field was carried out in the years 2017 and 2018 in the experimental field of the UKC Pohorski dvor in Hoče (400 m above sea level, 46 ° 30 '45 "N, 13 ° 30' 33" E). Water content in plants, the development phase of plants and environmental factors mainly affect the dryness of the hay. Hay drying in the field can be successful only if the relative humidity of the air is lower than the humidity of the material. Hay drying in the field at good weather conditions (temperature between 21 and 27 oC and relative humidity between 45 and 30%) lasts up to 2 days (usually 2 to 4 days). However, in both experimental years the time of harvesting and hay drying were significantly prolonged due unfavourable weather conditions.
Energy consumption analysis was carried out in two ways of haymaking with in field drying hay on family farms at different locations in Slovenia. Energy consumption of haymaking is determined from used mineral diesel fuel when performing various working operations with the tractor aggregate in one complete haymaking process (mowing, spreading, tedding, side raking, hay collection with self-loading wagon or collecting hay and baling with round baler). Total energy consumption for all working operations provides us with data on final energy consumption for haymaking in two different ways (hay collection with self-loading wagon or collecting hay and hay baling with round baler). The average total energy consumption (from mowing to hay baling) per hectare area (MJ ha-1) during hay making with hay baling in round bales is higher by 27.6 % than the average total energy consumption (MJ·ha-1) in hay making, when hay is loaded with a self-loaded wagon (energy from mowing to loading hay with self-loaded wagon). In hay transport, average hourly energy consumption (MJ·h-1) used to transport round bales is 24.1 % higher than hourly energy consumption for hay transport with self-loaded wagon. The average hourly energy consumption (MJ·h-1) for manipulation with round bales is 6.5 % higher, compared with the working operation of unloading of self-loading wagon and the transport of hay from a self-loading wagon with the hay blower in the hay storage
Changes in the content of crude protein (CP) and net energy for lactation (NEL) during the field drying (29 comparisons) and barn drying of herbage (19 comparisons) were studied at seven Slovenian farms. The duration of field drying lasted on average 30 hours when the drying conditions were favourable and 107 hours when they were unfavourable. At the harvest time, the average forage dry mater concentration was 645 g per kg. During the field drying under favourable weather conditions, the concentrations of NEL and CP decreased by 0.17 MJ and 6 g per kg of dry matter on average while during the drying in adverse weather conditions they decreased by 0.64 MJ and 2 g per kg of dry matter. During the barn drying using the cold air ventilation the concentrations of NEL and CP decreased by 0.15 MJ and 6 g while in case of drying with warm/dehumidified air they decreased by 0.03 MJ and 3 g per kg of dry matter on average. We conclude that during the haymaking in ideal conditions (favourable weather and drying with warm/dehumidified air), the concentration of NEL is decreased by about 0.2 MJ while in in less favourable conditions (short-term rain, autumn weather and drying on cold air dryers) it decreased by about 0.8 MJ NEL per kg of dry matter. Regardless of the hay making procedures the decrease in CP content is relatively small, i.e. below 10 g per kg of dry matter. It should be emphasized that the data were obtained from farms that use barn drying facilities and which pay above average attention to hay making procedures.