Vibrators are widely used in agriculture, such as for vibrating trees to harvest fruits and nuts, or for vibrating screens to separate different materials (e.g. plants and soil or grain and debris) in the harvesting process. Traditional vibrators are bulky and configured with fixed mechanical transmission, so they cannot be precisely controlled and cannot adapt to different conditions, causing negative effects such as ineffective vibration or damaging tree barks. In this paper, a full-directional and lightweight electric vibrator is designed. The unidirectional vibration force is produced through the utilization of two centrifugal forces that are generated by the eccentric mass rotation of two motors. Firstly, the vibration direction can be adjusted to any direction by adjusting the meeting position of the two centrifugal forces. Secondly, the vibration force can be adjusted by changing the motor speed, as the centrifugal force is proportional to the square of the rotation speed. The vibrator is tested with laboratory bench experiment and with agricultural application for vibrating a tree. The prototype vibrator can produce 680N with the weight of 7.2kg, the force can be further improved by increasing the eccentric mass, increasing the rotation speed or decreasing the rotation arm length. The vibrator can be applied to smart agriculture, such as nut and fruit harvesting, or adaptive vibration screening.

Present study concerns one of the basic causes for cracking of sweet cherry fruits as a result of increased rainfall, and this amount is different for different soils. The study was done for the soils at the experimental orachard of the Institute of Agriculture - Kyustendil, Bulgaria, which are Chromic Luvisolssoils with acidity pH = 4.5-6.0. This soil is rich of the clay mineral montmorrilonite. As a result of extreme rainfalls the soil in the studied experimental field, the clay mineral montmorillonite starts to separate sodium Na, The area is rich also of chloritized slates which enriched the soil of chlorite Cl as the result is - salinization of the soil, enriching of NaCl.The amounts of precipitation needed for soil salinization, which causes damages - ckracking of cherry fruits. As a result of the present study, the critical amount of precipitations, causing damages - cracking on sweet cherry fruits is estimated on about 28 l/m2. With these amounts of precipitation, a deterioration in the quality of the crop can be expected and even with forecast amounts of precipitation, it can be counteracted by adding of agricultural gypsum(the mineral gypsum) to the soil, according to the cited reference. In 2024, because of the high precipitations level, the salinity of the soil was very high in NaCl and this was the cause for which the harvest of sweet cherries was lost as many cherry trees died.