Paper analyses the influence of long-term mineral fertilization on the improvement of aggregate structure durability of luvisols under monoculture cultivation. Dynamic and static water resistance as well as the state of secondary aggregation were investigated. It was found that both NPK and NPK+Ca fertilization improved the above-mentioned parameters, especially the state of secondary aggregation, by an order of several percent. This was particularly evident on the plots where cereals were cultivated, particularly the rye. It is assumable that a direct cause of improvng soil structural condition was more intensive development of plant root systems resulting in a noticeable increase of soil humus content in the treatments with rye and barley. Positive impact of humus on the increasing in quantities of secondary aggregates was confirmed by the results on plots fertilised with farmyard manure where their amounts were the highest.
The present experiments were earned out pn the soilrf of the Rybocice polder near Swiecko, which was purposefully flooded with waters of the Odra river during the summer flood of' 1977 that causet complete destruction of crops and meadow sward. The flooded areas remained under water for more than 30 days. The dominant soils found in this area are river alluvial soils (Fluvi- sols) of varying texture. Rceause of their location and poorly operating drainage system, the discussed soils are periodically too wet by nature or water-logged. In the spring (March/April) of 1998 the ground water table occurred at the depth of 30 cm on damaged grasslands and at 90 cm on some arable Holds. The content of organic carbon ranged from 0.7 to 3.2% in horizon A with depth of approximately 30 cm. Soil reaction was found to vary considerably - from pH (KCI) 4.2 to pH 7.6. Long purposeful inundation with flood waters was not found to have caused significant negative effects on chemical properties of the examined soils. No noticeable contamination with heavy metals (Pb„ Cu, Zn, Cd, Cr and Mn) or polieyclic aromatic hydrocarbons (PAH) was observed. Bulk density in this region, without any treatment from the period of flooding to the spring of 1998 was approximately 1.60 Mg/m3 as compared with 1.40 Mg/m3 on the field cultivated (ploughed) in spring and sown with spring cereal. The mean crop yield in 1998, when appropriate agro-techniques were applied, did not vary significantly from the long-term averages.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.