Fine root biomass and soil properties following the conversion of miombo woodlands to shifting cultivation lands

Abstract

Fine root (Fr) biomass, soil organic matter (SOM), and soil organic carbon (SOC) and soil total nitrogen (STN) stocks are affected by land use. Conversion of woodland to agricultural land is reported to result in depletion of SOC and STN stocks. However, information on Fr biomass, and SOC and STN stocks changes following conversion of miombo woodlands to shifting cultivation lands is lacking and might be highly variable depending on the shifting cultivation system practiced. Swidden agriculture is the most complex and multifaceted form of agriculture in the world and it is a highly diverse land use system. It was expected that conversion of miombo woodlands to shifting cultivation lands would result in decreased Fr biomass, soil organic matter (SOM), and SOC and STN stocks as a result of the removal of the trees, soil burning, and other vegetation disturbances typical of this agricultural system. The results showed that the conversion of miombo woodlands to swidden agriculture lands did not impact SOM, SOC and STN stocks; however, it led to a loss of 52% of Fr biomass. In miombo woodlands, Fr biomass and the soil properties (SOM, SOC, STN) were significantly dependent on basal area (m2 ha−1). In swidden agriculture lands, they were dependent on stump cross-sectional area (m2 ha−1). Shifting cultivation lands have the potential to store as much organic matter, C and N in the soil as miombo woodlands, depending on the form of shifting cultivation practiced. Further researches are required on different forms of shifting cultivation practices and its impacts on soil properties.