Effect of fragmentation and pacing at spot ploughing on dry soils

Seedbed preparation to achieve desired aggregate size requires many tillage operations when performed on dry soil. A very common implement used for the initial operation is the moldboard plough, subsequent passes may include disk, chisel ploughs, cultivators, rototillers and harrows. Therefore ploughing should form flat soil surface to ensure favorable conditions for performance of subsequent operations. Mechanical reconsolidation by fragmenting and packing at spot ploughing on dry soils was studied in a soil bin, and on loam soil in the field. The results show that in dry soil fragmentation by ploughing and packing is attained by tearing the natural clods from each other and by stressing and translocating them. The maximum bulk density after ploughing was about 964 kg m-3, after ploughing and packing was about 1071 kg m-3 . Packing considerably reduced soil surface roughness from about 0.12m to 0.04m. Moreover, packing by rolling increased soil fragmentation from about 68.2 % (after ploughing) to 79.8 %. A series of experiments showed that the roller had only a slight influence on draught resistance. The spot ploughing draught were increased about 1.3% at this operating conditions.