Viljelussüsteemide mõju mulla süsinikuvarule

Maintaining or enhancing the stock of soil organic carbon (SOC) is a key factor in sustaining the soil resources of the world. The objective of this research was to study the effect of different farming systems (conventional farming with mineral fertilizers vs. organic farming with organic fertilizers (catch crops and composted manure)) under the same 5-crop rotation system on the SOC stock. Data presented in this paper concerned the first rotation during 2008–2012. The main factors were farming systems: conventional and organic. Four conventional farming systems differed in the mineral nitrogen application rates. In two organic farming systems catch crops were used with or without composted solid cattle manure. The SOC stock was determined before experiment and after the first rotation. The stock of SOC increased considerably after the first rotation only in the organic farming systems, where the total C-inputs were higher compared to the C-inputs in conventional systems. The use of mineral N contributed to no change in SOC stock but influenced the quality of soil organic matter. This research revealed that, compared to the other studied systems, in a system in which the highest rate of mineral N was used the more stable C fraction of SOM proportion increased.