General Studies and Communication Skills

Discuss the impact of livestock farming on the environment and natural resources management.

Livestock farming supports the livelihoods of many people globally and livestock farming has intensified. However, these activities have impacted negatively on the environment in the following ways:

The digestive food system of ruminants causes enteric fermentation which releases greenhouse gases such as methane (CH4), carbon (IV) oxide (CO2) and nitrous oxide (N2O). Activities such as slaughtering animals, processing meat products, waste disposal, treatment and compost manure preparation also release greenhouse gases. Other livestock-related activities such as transportation of refrigerated animal products like milk, meat and fish to the market release carbon (IV) oxide gas. Methane (CH4), carbon (IV) oxide (CO2) and nitrous oxide (N2O) trap and prevent heat radiation, from the sun from escaping the earth’s surface. The trapped heat increases temperatures on the earth’s surface causing global warming.

                                  

Intensification of livestock farming releases more greenhouse gases which continuously warms the earth.

Identify possible solutions to global warming as a result of livestock farming activities.

Overstocking and overgrazing destroy vegetation cover. For instance, in sub-Saharan Africa, many pastoralist communities keep livestock as a livelihood. The many animals trample on the land and eat up the available vegetation cover leaving the land bare. Without vegetation cover, the soil is exposed to soil erosion. The resulting effects cause desertification; another form of environmental degradation. Livestock-induced desertification causes loss of surface and groundwater, thus depleting water resources.

  

1. Identify possible solutions that can be put in place to reduce land degradation caused by livestock farming.

2. Are there farmers who carry out overstocking and overgrazing in the country?

3. How would you advice such farmers to ensure they adopt environment friendly activities?

Biodiversity refers to the variety of life on earth, that is, plants, animals, micro-organisms and the ecosystem in which they live, interact and which they depend for survival. Livestock farming leads to loss of biodiversity when animals destroy the vegetation cover. A large variety of plant species provide food for livestock. Overstocking and overgrazing damage and destroy plant species thereby altering the ecosystem on which fl ora and fauna exist. The loss of biodiversity endangers the life of plants, animals and micro-organisms on earth.

1. Explain ways in which livestock farming in your home area has caused environmental degradation.

2. Identify one region in Africa that faces desertification as a result of livestock farming.

3. Explain how desertification is caused by livestock farming in the region you have identified.

4. Discuss ways in which you would advise farmers in those regions to avoid further environmental degradation.

5. Examine measures that can be put in place to replenish the lost biodiversity.

Crop farming provides humans and animals with food. However, crop farming has harmed the environment in the following ways.

Crop farming practices have continuously destroyed the biodiversity. Pressure on the available land for crop farming has led farmers to encroach on riparian lands (wetlands), forested areas and preserved areas for wildlife protection. The destruction of biodiversity destroys a large number of plant species and threatens food security.

              

1. Identify ways in which people have destroyed biodiversity in Rwanda to create land for crop farming.

2. Explain the effects of activities identified in question (1) above.

3. What are the possible solutions to problems caused by loss of biodiversity in the country due to crop farming?

Chemical compositions of inorganic fertilisers are washed away by rain water into the rivers or percolate deeply into the soils. This pollutes the water, causing hazardous effects to animals and human beings. When the chemicals are washed into rivers, lakes, streams and oceans, they kill algae present in the water and this leads to eutrophication. This process removes oxygen from the water killing the aquatic life present in form of flora and fauna. There is intensive and excessive use of pesticides and herbicides to control pests, diseases and weeds in farms. Use of pesticides and herbicides kills other animals, insects and micro-organisms leading to loss of biodiversity. For instance, bees which pollinate plants are either killed or kept off the farm by use of pesticides. Crop production relies on pollination and excessive use of pesticides leads to a decline in insects which pollinate plants. Crop yields are likely to decline in future due to absence of insects that help in pollination. Pesticides and herbicides are washed by rainwater into rivers and water bodies through soil erosion. As a result, aquatic life, such as fish and algae are killed (eutrophication). This also leads to contamination of water which is harmful to animals and human beings (water pollution).

                                      

Clearing vegetation on the earth’s surface to grow crops is one of the major causes of desertification. The destruction of vegetation breaks down the natural climatic system which maintains the hydrological (water) cycle. This, in turn, causes changes in climatic patterns. Desertification also causes loss of surface and underground water sources. In such a case, farming is likely to be unsustainable.

       

1. Explain ways in which crop farming in your district causes environmental degradation.

2. Identify measures which crop farmers can use to reduce environmental degradation and encourage for sustainable farming.

3. To what extent does population pressure in the country cause environmental degradation?

4. Discuss measures the government and other agencies have put in place to control population explosion.

5. Suggest possible ways of conserving agricultural resources in Rwanda to enhance food sustainability and food security.

6. To what extent do you think food security in Rwanda is sustainable?

Fertilisers are substances containing nutrients necessary for plant growth, improvement of soil fertility and boosting the crop yield. Mineral fertilisers are made from manufactured substances. They contain one or more nutrient. Th e following are the harmful eff ects of mineral fertilisers on soil and harvest.

1. Continuous applications of mineral fertilisers deplete soil nutrients and minerals that are naturally present in a fertile soil. This is because naturally present mineral elements in the soil, nitrogen (N), phosphorus (P) and potassium (K), are continuously depleted through plant uptake. Some of these mineral elements are washed away through soil erosion and leaching into the rivers. In the long run, this leads to soil mineral deficiencies and the soil loses its fertility.

2. Excessive use of mineral fertilisers damages the soil quality causing soil acidity. Converting mineral elements of nitrogen and phosphorus from one form to another lowers the soil pH value. A soil pH value of less than 6 is said to be acidic whereas a soil pH value of more than 6 is said to be alkaline. If the soil is acidic, then it reduces the population of nitrogen fixing bacteria in leguminous crops. Th is ultimately affects the crop yields. Soils which are moderately alkaline are conducive for healthy growth of plants.

3. Intensive application of mineral fertilisers such as ammonium nitrate and potassium chloride causes soil salinity (salt content in the soil). Excess salt in the soil reduces plant uptake of nitrates. A lot of phosphorus inhibit plant uptake of manganese and excess use of potassium in the soil hinders plant uptake of calcium. Too much salt also hardens the soil and may damage the plant roots. This results in stunted plant growth and poor crop yields.

4. Mineral fertilisers are high in nitrogen salts. When nitrogen is absorbed quickly by the soil, it will dehydrate and dry up the plants. This reduces the crop harvest.

5. Excessive application of mineral fertilisers may cause plant leaves to turn yellow or brown. This leads to reduced crop yields as a result of damaged plants. This is known as chemical leaf scorch. Scorched leaves wither and the plant may die thereby reducing harvests. Mineral fertilisers can also cause root burn as they do not allow enough water intake by plants. This leads to growth of weak plants are reduces crop yields.

6. Mineral fertilisers kill soil micro-organisms required in the breakdown of organic materials in the fertilisers. These micro-organisms are necessary for a fertile soil and healthy crop growth.

Debate the motion, ‘Mineral fertilisers are better than organic fertilisers in enhancing soil fertility.

Th ere are a number of ways of restoring soil fertility to support sustainable agriculture and improved crop productivity.

i) Use of organic fertilisers: Application of farm yard manure and mulching practices naturally restores the soil quality. Decomposing animal and plant products maintain and improve soil fertility. This, in the long run, attracts micro-organisms (for example bacteria) which play a critical role in soil aeration through cycling of nutrients throughout the soil composition and hence improving soil ecological stability. Micro-organisms further synthesise and rapidly decompose organic matter and ultimately, stabilise soil particles.

ii) Inter-cropping farming practices: Leguminous crops may be inter-cropped with non-leguminous crops. Leguminous crops are known for their nitrogen fixation in the soil.

iv) Integrated nutrient management practice: This is the process of maintaining soil fertility by the combined application of both organic and mineral (chemical) fertilisers. These combinations build up sustainable mineral elements in the soil by minimising soil nutrient loss and maximising crop yields. Mineral elements added to the soil in the form of application of mineral fertilisers only last in the soil for a short period whereas mineral elements contained in organic fertilisers last in the soil for many years (Cooke, 1970).

v) Application of limestone: Application of limestone into acidic soil reduces soil acidity and makes the soil more alkaline and conducive for the growing of crops. Limestone is known to neutralise soil acidity by making it alkaline.