Journal of Geography  & Natural Disasters
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Robust variation in the potentials of Tanzanian soils under sisal plantation to stabilize organic carbon and nitrogen: A Case of Handeni District

Msafiri Yusuph Mkonda

Understanding the impacts of tillage erosion on Soil Organic Carbon (SOC) and Nitrogen (N) fractions is essential for targeted soil conservation in cropland areas. SOC and N play significant role in the global Carbon (C) and N cycles. Establishing SOC and N stock is a good step towards implementing the “4 per 1000” (4p1000) initiative which was launched at the COP21 conference in Paris aiming to slow down the rising levels of atmospheric carbon dioxide (CO₂). Thus, it is essential to understand how much SOC and N are stored in the soil and if possible to determine how long these nutrients persist belowground. Previous studies indicate that the storage of SOC and N strongly affected the interaction of climate and minerals. However, most of these results have not consistently considered the cropland soils (sisal plantation) as specific ecosystem. In attempting this study, we sampled the sisal plantation of Handeni District because the area partly represents the grassland of Tanzania. Sixteen soil sampling points were established within ten hectares and they involved two soil depths (i.e. 0-20 cm and 20-40 cm) and two locations (lowland and upland). The results exhibit that there have been significant variations of SOC and N accumulations under the two soil depths and locations. In the lowland areas, SOC was 1.3 and 0.45 MgC ha⁻¹ for the depths 0–20 cm and 20-40 cm, respectively. Besides, in upland areas, SOC was 0.60 and 0.34 MgC ha⁻¹ for the depths 0–20 cm and 20-40 cm, respectively. Similarly, the total N was significantly higher 2.12 Mg (0-20 cm) in lowland than in upland 1.80 Mg (0-20 cm). The same pattern happened in the depth (20-40 cm) where lowland had 1.40 Mg and upland had 1.16 Mg. These insights in cropland soils allow us to infer that the alterations of SOC and N are significantly influenced by climate change and minerals. Biologically, the microbial activity and microbial biomass correlate with SOC and N. This means, different agro-ecological zones of the country can have different SOC and N storages.