The pot experiment was conducted to access the soil microorganisms biomass (physiological method – Substrate Induced Respiration) and emissions of N2O, CO2 and CH4 (photoacoustic infrared detection method), and grasses biomass (weight method). The obtained results of analysed gases were converted to CO2 equivalent. There was no effect of the microorganisms biomass on the N2O emissions. The increase in CO2 emissions was accompanied by an increase in the microorganisms biomass (r = 0.48) under the conditions of the I swath and acid soil reaction, as well as the II swath and neutral reaction ( r = 0.94). On the other hand, in the case of CH4 emission, such a relationship was noted both swaths under the conditions of neutral reaction ( r = 0.51), but a negative correlation ( r = –0.71) was noted for the acid reaction only at the II swath. The increase in the grasses biomass with the increase in the microorganisms biomass was recorded only at the II swath in neutral reaction ( r = 0.91). In a short period of time, with the neutral soil reaction with the increase in the soil microorganisms biomass, an increase in CO2 sequestration and biomass of cultivated grasses was noted. Information on the determination of the microorganisms groups responsible mainly for the transformation of carbon compounds and CO2 and CH4 emissions from the soils of grasslands would be valuable scientifically.

The study of changes in grassland was conducted on the territory of individual counties of the West Pomeranian Voivodship. Based on data collected in the Valorisation of the Agricultural Production Space of Poland and spatial data (an electronic 1:5000 soil and agricultural map) the basic information on the use of agricultural land in the 70s of the 20th century. Changes in use over time were analysed based on data the Statistics Poland (Pol.: Główny Urząd Statystyczny – GUS), General Geographic Database and The Agency for Restructuring and Modernisation of Agriculture Crop Register (Pol.: Agencja Restrukturyzacji i Modernizacji Rolnictwa – ARiMR).
The studies showed that in the West Pomeranian Voivodship, a successive decrease in the share of permanent grasslands (0.9%) and arable lands (1.4%) is observed. There is a spatial variation in the share of permanent grassland in the province’s counties, with a distinction between northern and southern counties. The main direction of change in grassland area is arable land, which applies to counties with the highest share of permanent grassland (PG) and counties with a high share of the best soils and forest direction. Land quality was the main factor determining the direction of grassland changes, with the best PG converted to arable land or for investment purposes. In contrast, the weakest were converted to forestry or spontaneously wooded through abandonment. The main reasons for changes in grassland areas in the West Pomeranian Voivodship were: conversion of use to arable land, afforestation of grasslands, land use for urban planning purposes, leaving land fallow and conversion for constructing fishponds.