Gintas Viselga

Research of Accuracy Parameters of the Gantry Course

A laser instrument maintains the course of the positioned gantry module. A laser beam generator emitting a vertical beam is placed at the end of the experimental field. A laser beam catcher with photo diodes is mounted onto a positioned gantry module replaceable support. Course deviations were assessed in two cases: when laser, straight-course maintaining mechanism was mounted at the same end of the spar as positioning trundle; and when it was mounted at the middle of the spar. Furthermore, we estimated how course deviations vary when changing the interaxial distance of laser catcher photodiodes. An electromechanical transmitter was used in the tests. The gantry module is positioned by a special positioning trundle and is run by a 12 V electric motor through a worm self - braking reduction gear.

Research of Soil Compression and Tillage Precision Parameters of Tractor and Gantry Units

The new generation of the tractors with the front and rear linking systems makes more perfect combined aggregates, when some of them are mounted on the front of the tractor and others on the rear of the tractor. Thus the soils can be significantly compacted by the wheels of the tractors.Gantry agriculture has great influence on the soil structure. The possibilities to minimize the interaction between the chassis and the soil compression of different types circular and shuttle gantry modules were theoretically investigated. The influence of the unevenness fields on curvature of chassis ways and to selection of the chassis types were investigated.

Ecological assessment of agrotechnical measures in sandy light loam soils@@@Agrotechninių priemonių smėlinguose lengvo priemolio dirvožemiuose ekologinis įvertinimas

In many European countries and in the USA, the dominant intensive technologies of the end of the last century have been recently replaced by farming technologies sustaining resources, soils and environmen – limited loosening of soil and a reduced number of tractor aggregate drives on the soil surface to avoid loamy soil compaction and to reduce its physical degradation and, concomitantly, erosion (Jankauskas, Jankauskienė, 2006). Soil density, hardness, compaction level, fractional composition and crumbling index are the main factors describing soil compaction. Potatoes are especially sensitive to soil compaction because they grow best and yield largest crops only when the soil is loose over the entire zone of potato plant formation. Otherwise, the yield and quality of potatoes reduce: potato tubers are small and have an irregular form unconformable with the requirements. Clods of earth getting among potatoes when harvesting with combine harvesters damage tubers and reduce their storage life. Th e mentioned factors considerably reduce the portion of marketable products in the total potato yield. For this reason, potatoes were chosen as the best agronomic testers of soil compaction. Th e timely and good quality preparation of soil for potato planting together with relevant fertilization and the least possible compaction of the zone of potato plant formation are indispensable for improving potato plant formation and growing (Klikocka, Sommer, 2003). To avoid soil compaction, fi rst of all it is necessary to abandon their fertilization with manure because this technological operation is performed in autumn aft er harvesting when the soil moisture regime is far from the optimal one. However, fertilization of soils with mineral fertilizers alone reduces the content of humus and makes the soil sticky. Th e time of physical maturity of soil when its crumbling index is highest shortens (Spiess et al., Potato as the most widespread agronomic culture was used for assessment of soil compaction caused by the new ecological farming technologies. Th e experiment was carried out in 1998–2007 growing potatoes in a sandy light loam soil. Th e infl uence produced by diff erent types of tractors (traction classes 6 and 14 kN) used for potato planting and the care of potato crops on soil compaction in the technological tracks and ridges was compared. Th e experimental technology was based on the use of a cultivatormulcher with the horizontal rotor whose symmetrical axis is perpendicular to the direction of movement. It was compared with the traditional technology when the soil ploughed in autumn is cultivated and harrowed in spring before potato planting and later when potato haulms are stalking. Th e compared parameters included the infl uence of mulching and repeated driving of tractors on physical soil properties in the tracks: density, hardness, compaction level, fractional composition and the crumbling index. Th e structure of the study soil was seriously damaged by aggregate carriers. Aft er three drives, soil density in tracks approached the limit value suitable for plant cultivation (1.6 g/cm3). Th e compaction level in the 16-cm surface soil layer increased 1.10–1.65 times. In deeper layers, its value quickly approached 1. As a result, the physical degradation and cultivation resistance of soil as well as energy input for soil cultivation increased. Th e environment was increasingly polluted with exhaust gases. Th erefore, the ecological experimental technology of potato growing requires reducing the number of drives between the rows. Applying the common technology, the soil crumbling index reached 78.5% using the tractor T-25, and 82.9% using the tractor MTZ-82. Applying the experimental technology, these indices were 73.0% and 78.7% respectively. Th e potato plant mass grown applying the traditional technology and using the T-25 tractor (with narrower tyres) was by 30.2% larger than the plant mass grown using the MTZ-82 tractor (wider tyres). In the mulched soil with a lower compaction value, the potato plant mass was even by 46.1% larger.