The effect of physical soil properties on metabolism and technological quality of sugar beet

In the four trial years 1996-1999 the basic physical parameters of beet gro wing soils in the region of the Dobrovice sugar plant were measured, in par ticular the degree and depth of soil compaction by penetrometer and physica l soil properties by undisturbed soil sampling. Chlorophyll content measure d by chlorophyllmeter, pH value of beet juice in leaves and roots, numbers of leaves, weight of roots and leaves, sugar content, concentration of alph a-amino N, potassium and sodium were determined in parallel trial. It was r epeatedly found in all the years that penetrometric soil resistance in head lands was higher by 60-90% than in the inner parts of lands. It gradually i ncreased from the beginning of vegetation until harvest. Until the formatio n of the 6(th) pair of true leaves penetrometric soil resistance in rut-row s was significantly higher than in the rows and inter-rows of sugar beet st and. The dynamics of soil porosity in the course of vegetation was in logic al correspondence with changes in bulk density of soil. Chlorophyll content and root weight showed the relatively closest negative correlation with pe netrometric soil resistance in the whole set of measured data (-0.61 and -0 .58, respectively). Sodium and potassium contents were less affected by soi l compaction. The data proved higher penetrometric resistance in the ruts o f harvesters after harvest and removal of sugar beet from the field. The mi nimum;relative increase in comparison with the value of penetrometric resis tance before harvest was 20%.