The higher organic matter content upstream may be attributed to a higher accumulation of organic matter due to high inputs from root biomass . Variability in total nitrogen is linked to difference in soil organic matter content, intensities in cultivation and erosion, application of manures, pesticides and fertilizers rich in nitrogen content in the soils . The mean values and standard deviation of soil physico-chemical variables at different sampling sites along the two rivers of Chemosit and Kipsonoi are presented in Table 3. In this study , soil pH ranged between 4.42 and 5.56, implying the soils are strongly acidic and suitable for tea production which was consistent with previous studies carried out in tea plantations . Soil pH was lowest in soils obtained Upstream on both rivers, with significant differences across the sampling sites. Tukey’s test showed that soil pH at upstream differed significantly from soil pH recorded midstream and downstream of Chemosit and Kipsonoi rivers.The low soil pH at the upstream corresponded with a high soil organic carbon at the same site Total organic carbon did not show significance difference, however the levels varied across sampling sites along the Chemosit and Kipsonoi rivers.
Variability in total organic carbon along the two river systems is linked to the reduction in organic material being returned to the soil system due to decreasing vegetation cover downstream and oxidation of soil organic matter as a result of continuous cultivation along the riverbanks, uncontrolled grazing and browsing,tower garden loss of organic matter by water erosion and removal of green materials. These results are in agreement with other studies that reported that the soil organic content differed with different land use types . The higher organic matter content upstream along Chemosit river may be attributed to a higher accumulation of organic matter due to high inputs from root biomass . Nitrogen and posphorous are categorized as essential nutrients in the soil for growth and development of plants. Soil nitrogen at the upstream sampling site along Kipsonoi river differed significantly from that of Midstream and downstream sampling sites. There was no significant difference in total nitrogen along Chemosit river. Variability in total nitrogen on both rivers is linked to difference in soil organic matter content, intensities in cultivation and erosion, application of manures, pesticides and fertilizers rich in nitrogen content in the soils .
For example, it is possible that nutrient uptake by crops, leaching during heavy down pours or further removal during plant harvest time could have contributed to the relatively low soil nitrogen content at the midstream of the two rivers compared to other sampling sites .Variability in total phosphorous is related to the application of animal manure and application of diammonium phosphate fertilizer on the adjacent farmlands. Lower phosphorous content in the soil along Kipsonoi river as compared to Chemosit river could be related to phosphorous fixation especially in forested areas, crop harvest in agricultural farms and erosion by water . Highest content of phosphorous was recorded at the Midstream of Chemosit river majorly dominated by large scale tea production and lowest downstream of Kipsonoi river. According to Matano et al. , land use has a significant effects on soil chemical properties. The levels of soil nutrients can be used to deduce the degree at which a given site is degraged. Potassium levels could be attributed to the relative pumping of potassium from the subsoil by vegetation in the forest land. Lower potassium levels downstream could be attributed to soil degradation and losses by leaching due to reduced vegetation cover . Figure 3 and Figure 4 report the amount of Cadmium, copper and lead in soils along Chemosit and Kipsonoi river. Cadmium showed lowest concentration as comparedto copper and lead. However, considering the Canadian soil quality guidelines, all the metals were within the maximum allowable values for agriculture soil; 50 – 60 mg/kg; 1.4 mg/kg and 70 mg/kg ranges for copper, cadmium and lead, respectively .
Our dependent variable, age at initial diagnosis of CLL, may or may not carry implications for long term management of diagnosed CLL but is presumably strongly correlated with the age at which CLL is initiated. CLL is assumed to be initiated by a mutagenic event which fails to be lysed by cellular or subcellular maintenance/repair or immunological processes. Thus association of a potential risk factor with early AAID-CLL may reflect increased: 1) likelihood of early detection , 2) greater exposure to mutagenic risk , or 3) failure of cellular monitoring/ maintenance/repair/proliferative processes, or all three. The last of these possibilities is the most exciting because the independent predictors of AAID-CLL may reflect controllable events with the possibility of influencing the onset of the illness. Present results replicate previous studies in finding that farming/pesticide exposure and ASA use may have beneficial effects for the onset of CLL. While early life pesticide exposure is not reversible, ASA use clearly is for most patients. It is difficult to conceive of a well executed controlled clinical trial of ASA since it is universally available and patients agreeing to participate in such a trial would be tempted to dose themselves. None the less, naturalistic studies of patients who are “spontaneously” taking ASA and following disease progression seem feasible and potentially enlightening. Exercise has not previously been investigated as a factor in onset of illness for CLL. Our patients who reported themselves as having always been “Fit” had later diagnosis of CLL, but reported Hours of Exercise per Week was negatively related to age at initial diagnosis—an apparent paradox and, perhaps, an artifact of our sample sources. Like ASA, naturalistic observation of “spontaneously” occurring exercise and course of illness seems feasible, while a controlled clinical trial would also be difficult to execute because of patient compliance. Perhaps most impressive among our findings is the observation that multiple measures of emotional distress are associated with earlier onset CLL. It has been known for several decades now that some measures of ED are associated with suppression of some immune parameters. More recently, ED has been implicated as a cause of diminished telomerase levels, telomere shortening and diminished DNA repair capacity. Because of the complexity of both the psychoneuroendocrine and immunological systems, other possible mechanisms may remain to be discovered. Because knowledge of mechanisms is unnecessary, although reassuring, for the clinician, advancements in clinical research can proceed unimpeded by the mechanism conundrum. Our results may imply four new avenues for delaying the onset of CLL: ASA use, being “Fit”, smoking avoidance and treatment of ED.
Given the widely recognized safety of these potential therapies, we believe prospective clinical observation studies and, stacking flower pot tower more credibly, clinical trials should be considered. Present results must be interpreted in the context of the limitations of our methods. For practical reasons , our patient sources were mixed, with one source not permitting independent checking of records to affirm the patient’s report. It is likely some error was introduced into our dataset by this method, although we cannot determine how much. But is it likely to be systematic error that would have biased our results in favor of our findings? We think not. Future work should strive to independently ascertain CLL diagnosis and WBCs. In addition, present results need confirmation in a prospective study or, better still, intervention study. The latter is the only true experiment in risk factor research and the “gold standard” for determining causality. Sub-Saharan Africa region, especially the Sahel area, experienced a constantly growing degradation of its environmental characteristics since several decades. This degradation is characterized by the deterioration of the major components of the ecosystems such as soil, vegetation and water. Among these components, soil degradation or land degradation affects lives and income of millions of people, especially those living in rural areas. This degradation results from climate-induced drought and a variety of unsustainable agricultural and forestry management. In the Far North region of Cameroon, it results in the appearance and expansion of bare and crusted spaces unable to sustain agricultural and pastoral activities. These degraded lands, widespread throughout Sub-Saharan Africa region in general, are known as hardé in the Far North region of Cameroon, a term borrowed from Fulfulde language of the Maroua region, equivalent to naga in Chad and zippelé in Burkina Faso. Around 13% of the total land area in the Maroua region is degraded due mainly to mechanized cotton mono-cropping by hundreds of local farmers with fertilizer inputs supplied by the cotton industry, shifting cultivation, overgrazing, over-harvesting of fuelwood, uncontrolled forest fires and high population pressure. According to the level of land degradation, many initiatives have been undertaken for soil rehabilitation. Among them, the most significant initiatives include those of national and international institutions , government programs and projects, and at last civil society organizations and national or international NGOs. Those initiatives are mainly improvement of traditional techniques, including bunds, earth dikes, small dams, half-moon, Zaï method or planting holes, mineral fertilizer booster, herbicides, selected seeds and mechanization of hard work and today direct-seeding mulch-based cropping systems . Despite the robustness of financial and material resources used in the implementation of these initiatives, it is clear that they have localized and ephemeral efficiency, but also inconclusive results. To cope with this problem, farmers further develop skills learned from their ancestors. Very few studies have been devoted to the role of villager activities, their contributions to the dynamics of hardé soils rehabilitation, whether individual or collective actions. However, some studies on the characterization and rehabilitation trial of these hardé soils have been carried out. However, the question is whether farming communities in the Maroua region can develop actions promoting hardé soils rehabilitation through their own efforts, since modern technologies have inconclusive results.
The present work proposes to analyze local initiatives of hardé soils rehabilitation in the Maroua region. That is to identify and describe the local initiatives of hardé soils rehabilitation, to assess the impact of local initiatives on the hardé soils rehabilitation process and finally to evaluate the different constraints related to the implementation of various local techniques of hardé soils rehabilitation across the study area. To do this, two study sites have been selected, Mizileng and Zokok, all located in the Maroua region, in the Far North Region of Cameroon.Fieldwork consisted of conducting observations and surveys beside farmers in the two study sites, Mizileng and Zokok . Approaches used were essentially based on semi-direct interviews. Semi-direct interviews allow respondents to speak freely on the subject with a minimum intervention of the person conducting the interview. Individuals subjected to the interview were randomly selected. In order to obtain more reliable information, heads of household or individual of age equal or greater than 25 years were chosen. In each site, structured questionnaires, administrated to a sample of 100 farmers, were used to collect qualitative information on the different aspects of hardé soils rehabilitation. The administration of each questionnaire took about one hour for men and more for women. The total survey in both sites was completed after three months. The information collected include perceptions of farmers on land degradation, local knowledge on hardé soils rehabilitation, actions carried up and changes observed, impacts of local initiatives and constraints, knowledge of national and international organizations working for the rehabilitation of hardé soils and their views on the possible role of local actions in the regeneration process of hardé soils in their area. To complete information provided by the local population, visits were undertaken in the rehabilitated plots and plots being rehabilitated in order to observe the various actions taken by farmers in the different study sites. After data collection, Excel software was used to type and analyse data. All the respondents participated in each questionnaire. In the counting phase, responses were classified and corresponding percentages were calculated, based on the number of respondents. In this study, it is about descriptive statistics .In the localities surveyed, people are unanimous that land resources in their region are deteriorating day after day.