Three different types of nozzles (different wear rate) were used in this study. They are classified depending on the severity of their wear to three groups: new, worn and damaged nozzles. Those nozzles were spraying with the same application rate (303 l/ha) on two-year field trials; this was achieved by changing the spraying pressure for each group of nozzles in order to get the same application rate. This practice is usually done by operators of sprayers, who calibrate the sprayers on the same application rate every year without changing the nozzles, so they tend to reduce the spraying pressure in order to compensate the flow rate increase due to the nozzles yearly wear. Two types of plant growth regulators (PGR) agents were used in this study, namely: Moddus and Kelpak, they were applied to wheat plants field to reduce lodging. The results showed that applying PGR in the year 2015 produced an increase in the wheat yield and reduction in the plant height regardless the nozzle type, although there was not any occurrence of wheat lodging. In the year 2016, the new nozzles produced higher values of wheat yield than other two types of nozzles.
Agricultural nozzles usually produce a different drops size depending on the pressure and the physical condition (work life) of the nozzle besides producing a wide range of the drops spectrum in the spray cloud. In this paper the standard flat fan nozzles were investigated regarding the effect of the working pressure and the nozzle physical condition (new and worn nozzles). The size of drops and the spectrum of drops across the long axis of the spray pattern were examined by using Sympatec GmbH Laser Diffraction. Reducing the working pressure from 3 to 2 and then to 1 caused production of larger drops, also using worn nozzles (especially with lower pressure) changed the drops size which is expected to be produced from the new nozzles. The standard flat fan nozzles produced a wide range of the drops spectrum inside the spray cloud, generally small drops (less than 150 µm) concentrated in the middle of the spray pattern while the big drops (250-350µm) were situated on the edge positions (70 cm from the centerline) of the spray pattern.
Two tests were carried out to measure the standard flat fan nozzles wear during a specific period of an accelerated wear procedure. The first test aimed at getting 10% increase in the flow rate compared to the nominal flow rate, which is the threshold to replace the nozzles according to the nozzles testing standards. The second test was to wear the nozzles intensively (100 hours of accelerated wear), which represents the use of nozzles beyond the allowed threshold. The results showed that the flow rate reached 1.31 l·min−1 (equal to 10% increase) for the tested nozzles after 35 hours of the wear test. For the second test, the 10% increase of the flow rate was reached after approximately 30 hours. The wear rate reached 27.5% at the end of the test and this is 2.7 times more than the standardized threshold.
The aim of the study was to assess the selected physical characteristics of the briquettes of English ryegrass waste biomass and its mixtures with waste components from the agri-food industry: pea husks and oat middlings. The raw materials used for the tests are characterized by high calorific value and low ash content. Among the tested raw materials, the most favorable values were recorded for oat middlings in this respect. The produced briquettes were characterized by high volumetric density and very diverse mechanical durability. At the same time, the results of the tests on the mechanical durability of briquettes indicated that the use of components of ryegrass mixtures selected for testing brought unsatisfactory results, as compared to other analyzed physical and energy features.