Soil organic matter increase: Comparison between two strategies

The effects of different management practices, such as the traditional tillage system (deep ploughing) with compost addition, and a conservative one (minimum tillage), on soil organic matter and macroporosity are investigated. A three-year research (2005-2007) was performed on a silty clay loam soil under sorghum (Sorghum bicolor L.) continuous cropping. The comparison between the experimental data of the first and the third year, at the end of each cropping season, shows a significant increase in both total extractable (TEC) and humic organic carbon (HC) at 0÷10 and 15÷25 cm depth, for the compost treatment (COM) only. In minimum tillage (MT) a noteworthy raise is observed for total organic carbon (TOC) in the upper layer, while all the chemical parameters remain constant in both the layers of the control soil (T). As a whole, COM and MT soils exhibit the best structure. In COM a noticeable percentage of elongated transmission pores is mostly represented, probably related to high humic fraction amounts. In T low macroporosity values point out the occurrence of compact soil.