Safe and reliable drinking water availability constitutes a nightmare in many towns of developing countries and is usually appreciated from its physical appearance without prior knowledge of its chemical and biologica...Safe and reliable drinking water availability constitutes a nightmare in many towns of developing countries and is usually appreciated from its physical appearance without prior knowledge of its chemical and biological properties. This study investigates the suitability of groundwater for domestic and irrigational purposes through physico-chemical and bacteriological analyses in the Northern part of Bamenda Town (Cameroon). Thus, 20 groundwater samples were collected from hand-dug wells and spring sources in September 2018 (rainy season) and February 2019 (dry season) and physico-chemical and bacteriological characteristics were determined. The results revealed that pH ranged from 5.5 to 6.6, thus enabling the classification of the water as slightly acidic. Electrical conductivity varied between 0.01 - 0.06 μS/cm. The relative abundance of ions was such that Ca<sup>2+</sup> > K<sup>+</sup> > Mg<sup>2+</sup> > Na<sup>+</sup> for cations and <span style="white-space:nowrap;">HCO<sup>-</sup><sub style="margin-left:-7px;">3</sub></span> > Cl<sup>-</sup> > <span style="white-space:nowrap;">NO<sup>-</sup><sub style="margin-left:-7px;">3</sub></span> > <span style="white-space:nowrap;">SO<sup>-</sup><sub style="margin-left:-7px;">4</sub></span> for anions. The water types were Ca-Mg-NO<sub>3</sub> in both dry and rainy seasons. The results revealed that the mechanisms controlling groundwater chemistry are rock weathering and atmospheric precipitation. Indicator bacteria such as <em>E. coli</em>, <em>Shigella</em>, <em>Enterobacteria</em>, <em>Vibrio</em>, <em>Streptococcus</em> and <em>Staphylococcus</em> were detected in the studied groundwater samples, thus the water sources may pose a threat to public health.展开更多
This paper studies the effect of basalt and tephra dusts,as alternatives to chemical fertilizers,on soil fertility and Radish(Raphanus sativus)production.The experiment was conducted in the field and in the labo...This paper studies the effect of basalt and tephra dusts,as alternatives to chemical fertilizers,on soil fertility and Radish(Raphanus sativus)production.The experiment was conducted in the field and in the laboratory in the years 2017 and 2018 on two separate plots so as to annul residual effects of fertilizers).The experimental design in the field was a randomized complete block design(56 m^(2)),including five treatments and three replications:control(T_(0)),basalt dust(T_(1)),tephra dust(T_(2)),effective micro-organism(EM)fertilizer(T_(3))and NPK 20-10-10(T_(4)).The main results show the following decreasing trend based on yield:T_(1)>T_(3)>T_(0)>T_(4)>T_(2).The best yields appear in T_(1) and T_(3) probably because they supplied the highest levels of soil nutrients to match the needs of the crops.Although T_(2) plants performed poorly,soil properties like pH.H_(2)O(6.14 to 6.49),sum of exchangeable bases,base saturation,available phosphorus and cation balance were improved after tephra treatment.T_(2) plants might have performed poorly due to intrinsic properties of the tephra dust like low availability of trace elements compared to T_(1) and T_(3).T_(4) plants show the highest number of leaves,leaf area index and plant height.The Fe,Mn,Cu and Zn levels in bulbs and leaves will not pose danger of toxicity to human upon consumption and could serve as nutrient supplement for children and expectant mothers.The most profitable treatment is T_(1) permitting to recommend the popularization of basalt dust for radish cultivation as an alternative to chemical fertilizers.展开更多
文摘Safe and reliable drinking water availability constitutes a nightmare in many towns of developing countries and is usually appreciated from its physical appearance without prior knowledge of its chemical and biological properties. This study investigates the suitability of groundwater for domestic and irrigational purposes through physico-chemical and bacteriological analyses in the Northern part of Bamenda Town (Cameroon). Thus, 20 groundwater samples were collected from hand-dug wells and spring sources in September 2018 (rainy season) and February 2019 (dry season) and physico-chemical and bacteriological characteristics were determined. The results revealed that pH ranged from 5.5 to 6.6, thus enabling the classification of the water as slightly acidic. Electrical conductivity varied between 0.01 - 0.06 μS/cm. The relative abundance of ions was such that Ca<sup>2+</sup> > K<sup>+</sup> > Mg<sup>2+</sup> > Na<sup>+</sup> for cations and <span style="white-space:nowrap;">HCO<sup>-</sup><sub style="margin-left:-7px;">3</sub></span> > Cl<sup>-</sup> > <span style="white-space:nowrap;">NO<sup>-</sup><sub style="margin-left:-7px;">3</sub></span> > <span style="white-space:nowrap;">SO<sup>-</sup><sub style="margin-left:-7px;">4</sub></span> for anions. The water types were Ca-Mg-NO<sub>3</sub> in both dry and rainy seasons. The results revealed that the mechanisms controlling groundwater chemistry are rock weathering and atmospheric precipitation. Indicator bacteria such as <em>E. coli</em>, <em>Shigella</em>, <em>Enterobacteria</em>, <em>Vibrio</em>, <em>Streptococcus</em> and <em>Staphylococcus</em> were detected in the studied groundwater samples, thus the water sources may pose a threat to public health.
文摘This paper studies the effect of basalt and tephra dusts,as alternatives to chemical fertilizers,on soil fertility and Radish(Raphanus sativus)production.The experiment was conducted in the field and in the laboratory in the years 2017 and 2018 on two separate plots so as to annul residual effects of fertilizers).The experimental design in the field was a randomized complete block design(56 m^(2)),including five treatments and three replications:control(T_(0)),basalt dust(T_(1)),tephra dust(T_(2)),effective micro-organism(EM)fertilizer(T_(3))and NPK 20-10-10(T_(4)).The main results show the following decreasing trend based on yield:T_(1)>T_(3)>T_(0)>T_(4)>T_(2).The best yields appear in T_(1) and T_(3) probably because they supplied the highest levels of soil nutrients to match the needs of the crops.Although T_(2) plants performed poorly,soil properties like pH.H_(2)O(6.14 to 6.49),sum of exchangeable bases,base saturation,available phosphorus and cation balance were improved after tephra treatment.T_(2) plants might have performed poorly due to intrinsic properties of the tephra dust like low availability of trace elements compared to T_(1) and T_(3).T_(4) plants show the highest number of leaves,leaf area index and plant height.The Fe,Mn,Cu and Zn levels in bulbs and leaves will not pose danger of toxicity to human upon consumption and could serve as nutrient supplement for children and expectant mothers.The most profitable treatment is T_(1) permitting to recommend the popularization of basalt dust for radish cultivation as an alternative to chemical fertilizers.