engleski

Acid soils CO2 respiration under conservation tillage, different fertilization and liming

Good microbial activity plays a crucial role in soil health status and it is important for decomposition of organic matter, cycling of nutrients (especially P and N), formation of humus and stabilization of soil aggregates. It is known that Conservation tillage can positively affect higher accumulation of organic matter especially in the surface soil which can lead to a higher soil microbial activity. This activity can be measured through CO2 respiration from soil. Hence, the main objective of the study is how improved land management practices can affect evolved CO2-C which represents microbial activity as one of the most important soil health indicators. Two experiments were established in Croatia on two soil types Stagnosol and Gleysol both with acid soil reaction. Cultivated crop was corn and the treatments were: ST-Standard Tillage (deep mouldboard ploughing), CTD-Conservation System Deep (without ploughing and with minimum 30% of surface covered with plant residues), CTS- Conservation System Shallow (tillage up to 10 cm and minimum 50% of surface covered with plant residues). Liming CY- treatment with applied lime (according to recommendation) and CN-treatment without liming and fertilization, FR-according recommendation (NPK), FD-fertilization decreased by 50% compared to recommendation, GFR- fertilization according recommendation + 300 kg ha-1 Geo2 (biophysiological soil activator), GFD- fertilization decreased by 50% + 300 kg ha-1 Geo2. Soil samples were taken at two soil depths (0–15 cm and 15-30 cm). Measurement of evolved CO2-C is done by using commercial soil health test 24h Solvita CO2-burst test. CO2 respiration was significantly affected by tillage, fertilization and liming on both localities. Highest evolved CO2-C was measured on 15 to 30 cm on Gleysol (treatment CTS, CN, GFD) 193.00 CO2-C kg-1. On 0 to15 cm on both soil types the highest evolved CO2-C are recorded on CTS tillage treatments with liming and GFD fertilization (Stagnosol 95.37mg CO2-C kg-1 ; Gleysol 62.63 CO2-C kg-1). On both depths and localities, the lowest measured evolved CO2 was on ST. Concentrations of evolved CO2-C measured in CTS treatment confirms the positive influences of Conservation tillage on increasing microbial activity on acid soils especially in surface soil (0-15 cm) and also good applicability of Solvita CO2-burst test.

CO2 respiration ; conservation tillage ; fertilizer ; liming ; acid soil

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