| The main aim of this study was to assess the environmental impact of industrial agriculture, policies for pollution control, environmental protection and assessment in Rwanda:case study of tea plantations.The analysis of tea production in Rwanda revealed that in 15 years, Rwanda known an increase of 67,353,126 kg of green leaves from 18,344,961 kg in 1994 to 85,698,087 kg of green leaves in 2008 with 52,953,960 kg from tea growing area controlled by state tea factories and 327,040,129 kg from private tea factories.The results of this study show clearly the environment impact of Tea Growing in region in all aspects. Soil samples were collected in eleven zones among three locations per zone and were analyzed in the laboratory through pH Meter and the results indicate that the pH of all soil samples is less than 5 (pH<5) and the general average was found to be 4.4. The pH varies between 3.4 and 7.2 with an average of 4.69 at Mulindi; 4.2 and 4.6 at Shagasha with an average of 4.33; 3.8 and 4.3 at Sorwathe with an average of 3.92; 3.3 and 4.8 with an average of 3.97 at Gisovu; 3.2 and 4.6 at Gisakura; 3.6 and 4.6 with average of 4.43 at Mata; 3.7 and 4.7 with an average of 4.43 at Kitabi; 4.6 and 5.4 with an average of 5.06 at Nyabihu; 4.2 and 5.5 with an average of 4.9 at Rubaya; as well as 4.2 and 5.5 with an average of 4.93 at Pfunda and between 4 and 4.7 with an average of 4.44 at Nshili. The results indicate that the soil in the tea plantations in Country is acidic in general which can be considered as optimal for tea and this level of pH may result in deficiency of some base elements like calcium, magnesium, potassium and nitrogen.The analysis of water samples collected in some rivers located into the tea plantation areas has clearly shown the presence of many major elements (Al, As, Ba, C, Ca, Cu, Fe, H+, K, Mg, Mn, N, P, S, Si, and Zn). The analysis was done by using spectroscopy Technique Ms Instrument and indicated that their concentration differs by Tea plantation area. Seven elements were found with high concentration in all rivers. Among others Ca with concentration (mgL-1) varying between 37 and 54.9, C with concentration between 31.5 and 36.4, S with concentration that varies between 12.9 and 24.1, Mg with concentration that varies between 8.5 and 14.1, N with concentration varying between 4 and 11, and finally K which concentration varies between 5.3 and 7.8 were identified. It was also found that other elements had moderate concentration and these are Si, Cu, Mn, Ba, Fe, and P with the concentration in ranges 3.4-5.4; 1.1-2.5; 0.7-1.5; 0.5-1.03; 0.6-1; and 0.6-0.8 respectively. However, the analysis indicates that some elements were found with a low concentration such as Zn with the concentration that varies between 0.3-0.76; H+ with concentration between 0.4-0.66; Al with 0.4-0.6 and As with the concentration that varies between 0.02-0.5. In general this indicates that most of water in these Rivers flowing through tea plantation areas has a pH that is varies between 5.5 and 6.7. This implied that the water is acidic.The analysis based on water sample collected in Lake Muhazi helps us to establish the comparison between the pollution's levels in tea plantations and other source of water in the Country. It indicates that the average concentration of major elements in mgL-1 were:Al 0.33; Ba 1; C 31; Ca 43; Cu 1; K 6; Mg 12; Mn 1; N 5.1; P 0.3; S 16; Si 5; and Zn with 0.3 at Rwesero station. The average of As; Fe and H+ were negligible and were estimated to be 0. At Nyarubuye station the average concentration of major elements in mgL-1 were found as:Al 0.37; Ba 1; C31;Ca 44; Cu 41,H+ 1; K6; Mg 12; Mn 1; N 6.4; P 0.8; S 17; Si 5; and Zn with 0.5. Here the average concentration of As and Fe were also not significant and were estimated to 0. It indicates that the average concentration of major element in mgL-1 at Jambo Beach were:Al 0.31; As 0.23; Ba 1; C 30; Ca 48, Cu 1; H+ 1; K6; Mg 12; Mn 0.7; N 5.9; P 0.6; S 16; Si 5.1 and Zn 0.3 and the average concentration of Fe was also estimated to 0. In general, the analysis of major elements in Lake Muhazi was taken as the general sample of surface water in the country with no river flow, showing that the average concentration of those elements in mgL-1 are:Al 0.33; As 0.07; Ba 1; C 30.6; Ca 45; Cu 1; H+ 0.6; K6; Mg 11.6; Mn 0.9; N 5.8; P 0.5; S 16.3; Si 5; Zn 0.3 and an average concentration of Fe was not significant and were estimated to 0. The elements like Mg, K, N, and Si were found to have an average between 11.6 and 5. It is important to note that another group is composed of elements with low concentration (<5) and these are Ba, Cu, Mn, H+, P, Al, Zn, As and Fe.The results of the study reveal that several ongoing physical and chemical processes influence the water quality in Lake Muhazi and the water in the lake is basic with pH between 5.3-8.5 and conductivity (ohm cm-1)=2300-2460. The dominance of Ca, C and S can influence the metal toxicity in Lake Muhazi. The comparison between the level of pollution in Water from River in tea plantations area and water in other parts of country (Muhazi) indicates that pollutions level is different in two areas. Water is acidic in tea growing areas and this acidity may be due to the use of many fertilizers and pesticides with high NPK+Mg; whereas the water from Lake Muhazi is basic and this can be taken as a general case for other parts of the country. This basicity may be due to low quantity of NPK and Fe, plus the presence of many types of sediment carried out by erosion from different hill around the Lake.During this study, it indicates that the use of wood fuel by all tea factories and the most of rural habitants were the cause of the destruction of 1682.3 ha of forest every year in Rwanda. It is showing that Mulindi tea factory was a big consumer and it uses 137,643 m3 of wood fuel for the period of 15 years, followed by Sorwathe with 108,824 m3, Gisakura with 122,798 m3, Shagasha tea factories with 105,995 m3, 70,747 m3 of wood fuel were consumed at Kiatabi tea factory,70,371 m3 at Gisovu tea factory,66,387m3 at Rubaya tea factory 64,177m3 at Pfunda tea factory and 54,882m3 at Mata tea factory, Nyabihu with 36,994m3and Nshili-Kivu with 23,096m3. Also total of 5,047 ha of forests were destroyed in the country after Decentralization from 2006 to 2008 where desentroment was intense and the Provinces were reduced from 11 to only 4 plus the Kigali City, and the cutting of trees was at high level in Western and North Province with 1896 ha and 1768 ha respectively; 733 ha were destroyed in South province and 639 ha in Eastern Province as well as the Kigali city where deforestation of 1 lha were noticed. Its impact touches the country and whole region by loss of the rainfall.The result of this study indicates that in this period the use of wood fuel in many tea factories, restaurants, secondary schools, refugees camps, rural habitants in preparation of their food and the competition for agriculture land to support the population has led to many forests being cut down to make land for fields. Others immediate and long term effects of Rwanda deforestation are almost sure to threaten life on the country including the loss of biodiversity and playing an important role on Climate perturbation. Among 193 tree and plant species identified in country only less than 50 tree species are yet existing near to the tea growing areas and the majority of these tree species are only agro forestry planted by the population for a specific purposes like medicinal and treatment or other owner traditional objectives. It showed that only 43 tree species are identified around Shagasha, Kitabi, Mata, and Gisakura tea growing area each other; there are 38 remaining tree species at Gisovu, Rubaya, Pfunda and Nyabihu.36 tree species still exist near to Nshili-Kivu tea growing area; 16 tree species still exist around Sorwathe and there are only 15 tree species near to Mulindi tea growing areas.The deforestation impact was significant during the period from 1994 to 2008, where Rwanda had unregistered a temperate climate with temperatures of 24-30℃during the day; between 13-19℃at night throughout the year. And this study shows that the yearly rainfall in Rwanda from 1994 to 2008 was varied between 1448 mm to 1040 mm.The deforestation led to soil erosion and floods which destroyed a thousand hectares of plantations located on the mountainsides and valleys, and were a source of water pollution. It was revealed that the soil of Rwanda was degraded and washed away by water flow which implies a big problem of erosion. In order to protect the environment against different effects of erosion, it was revealed that many strategies were taken; among them for example are the dig and hedge anti-erosion and radical terraces. The measurement of erosion using the Method of Hole by capturing of water flow on mountainsides showed that the speed of this water was reduced from 1 hour in April 2007 to 7 hours 12minutes in April 2009.Economically, Tea agriculture contributed to the development of country by giving the job to about 55,215 persons in the whole country, and as exportation production it was a source of 34% of foreign income.Finally in this study, we proposed the methods and policies which can be applied in the country in order to ensure a sustainable tea growing and better environmental conservation. |
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