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首页> 外文期刊>British Journal of Environment and Climate Change >Soil Microbial Biomass Carbon, Nitrogen andSulphur as Affected By Different Land Uses inSeronga, Okavango Delta, Botswana
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Soil Microbial Biomass Carbon, Nitrogen andSulphur as Affected By Different Land Uses inSeronga, Okavango Delta, Botswana

机译：博茨瓦纳奥卡万戈三角洲塞隆加不同土地利用方式对土壤微生物生物量碳，氮和硫的影响

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Aim: The Okavango Delta at Seronga is fragmented into different land uses ranging from grasslands to woodland (Ximenia and mopane), often punctuated with cropped and fallow fields. The influence of land uses on surface (A1 horizon) soil physico-characteristics, nitrogen, sulphur, carbon, microbial population and biomass were studied to understand soil variability in order to devise conservation strategies for the area. Methodology: Total soil nitrogen (N) was analysed using a Leco N analyser, total carbon and sulphur by CS800 Carbon–Sulphur analyser. NH4+-N, NO3- and NO2- were extracted with KCl and determined using the indophenol blue method and by Griess-Ilosvay colorimetric method respectively. Microbial populations were determined by plate count method. Biomass carbon and flush of nitrogen were determined by fumigation and re- inoculation technique.Results: All the soils had a high sand content (> 85 %). Total soil N was generally very low, 0.017% in grasslands closest to the channel, 0.013% in cropped fields, 0.007% in fallow and lowest in woodlands (0.002%). Grasslands showed higher NH4+-N indicating low nitrification potential. Even if mopane woodlands had low total N, they had higher NH4+-N (0.067 ppm) and low NO2- compared to other land uses, this could be attributed to their inherent nitrification inhibition ability. No NO3--N was detected in these soils, probably due to the low nitrification ability and high leaching capacity of sandy soils. Microbial biomass C and population were highest in the grasslands and cultivated soils, while the woodlands had lower levels.Conclusion: Seronga soils have very low N, with the least in the woodlands furthest from floodplains. Grasslands closest to the channel basin had significantly higher total N, C and microbial biomass C but low S as opposed to the woodlands further from the channel. Cultivated areas had increased N and C levels and microbial biomass C compared to the woodland probably due to incorporation of crop residues and animal manure. The paucity of nitrifiers and undetectable NO3--N indicate a low nitrification potential and a high leaching ability of the soils. Fallowing of fields resulted in a decline in nutrient status.
机译：目的：塞隆加的奥卡万戈三角洲被分割成不同的土地用途，从草地到林地（西梅尼亚和黑猩猩），通常到处都是耕地和休耕地。研究土地利用对地表（A1地平线）土壤物理特性，氮，硫，碳，微生物种群和生物量的影响，以了解土壤的变异性，从而制定该地区的保护策略。方法：使用Leco N分析仪分析土壤总氮（N），通过CS800碳硫分析仪分析总碳和硫。用KCl萃取NH4 + -N，NO3-和NO2-，分别用吲哚酚蓝法和Griess-Ilosvay比色法测定。通过平板计数法确定微生物种群。通过熏蒸和再接种技术测定了生物量碳和氮的冲刷。结果：所有土壤均具有较高的含沙量（> 85 ％）。土壤总氮通常很低，最接近河道的草地为0.017％，耕地为0.013％，休耕地为0.007％，林地最低（0.002％）。草地显示出较高的NH4 + -N，表明硝化潜力低。与其他土地用途相比，即使丙烷林地的总氮含量较低，它们的NH4 + -N（0.067 ppm）和NO2-含量也较低，这可能归因于其固有的硝化抑制能力。在这些土壤中未检测到NO3--N，这可能是由于沙土的硝化能力低和浸出能力高。草地和耕地土壤微生物量碳和种群数量最高，林地水平较低。结论：芙蓉地区土壤氮含量很低，而距洪泛区最远的森林中最少。与距河道较远的林地相反，最靠近河道盆地的草地具有较高的总氮，碳和微生物生物量碳，但硫含量较低。与林地相比，耕地的氮，碳含量和微生物生物量碳增加，这可能是由于农作物残留物和动物粪便的结合。硝化剂的缺乏和未检测到的NO3--N表示土壤硝化潜力低且浸出能力强。田间休耕导致营养状况下降。

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