Effects of N-enriched rock powder on soil chemistry,organic matter formation and plant nutrition in lignite-poor sandy mine spoil in the forest reclamation practice

The effects of a slow-release N-enriched rock powder on soil chemistry, on the development of the soil vegetation (field layer vegetation), on the nutritional status of pine seedlings (Pinus sylvestris L.), and on decomposition rates of cellulose in lignite-poor mine spoils were studied. In the initial phase after afforestation fertilization caused a significant increase in NO₃ ⁻-N concentrations in the soil solution of the top-soil (0–60 cm). Subsequently, NO₃ ⁻-N concentrations of all N fertilized treatments decreased with the exception of the highest N application area (500 kg N ha⁻¹). This decrease of NO₃ ⁻-N concentrations was related to the establishment of a field layer vegetation, which developed according to the amount of N applied. In the above-ground phytomass of the field layer vegetation a maximum N accumulation amount of 22 kg ha⁻¹ was measured. Cellulose decomposition increased with higher N application rates. In the second year after N-fertilization, the pine needles indicated insufficient supply for almost all nutrients except for N. The deficiency symptoms were most pronounced at the plots that had received the highest amounts of nitrogen. This phenomenon appears to be related to the competition by the field layer vegetation. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date.