Agricultural Sciences Grade 11 P2 2014 Memo (Eng)

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER 2014 AGRICULTURAL SCIENCES P2 MEMORANDUM MARKS: 150 This memorandum consists of 11 pages.

Downloaded from hlayiso.com 2 AGRICULTURAL SCIENCES P2 (NOVEMBER 2014) SECTION A QUESTION 1.1 QUESTION 1.2 1.1.1 C √√ 1.2.1 D √√ 1.1.2 A √√ 1.2.2 E √√ 1.1.3 B √√ 1.2.3 G √√ 1.1.4 A √√ 1.2.4 B √√ 1.1.5 D √√ 1.2.5 A √√ (5 x 2) (10) 1.1.6 C √√ 1.1.7 B √√ 1.1.8 C √√ 1.1.9 B √√ 1.1.10 A √√ (10 x 2) (20) QUESTION 1.3 QUESTION 1.4 1.3.1 Autotrophs √√ 1.4.1 Energy √ 1.3.2 Parthenocarpy/parthenocarpy √√ 1.4.2 Dormancy √ 1.3.3 Scion √√ 1.4.3 Transpiration √ 1.3.4 Evaporation pan √√ 1.4.4 aquaculture √ 1.3.5 Flood/Furrow/Basin irrigation √√ 1.4.5 xylem √ (5 x 2) (10) (5 x 1) (5) TOTAL SECTION A: 45 Copyright reserved Please turn over

Downloaded from hlayiso.com (NOVEMBER 2014) AGRICULTURAL SCIENCES P2 3 SECTION B QUESTION 2: PLANT NUTRITION 2.1 2.1.1 Reasons for plants to have continuous water supply  Water transports nutrients from the soil to the roots and to the leaves/Water is the medium for nutrient transport in plants. √  Water transports the products of photosynthesis from leaves to the plant organs where it is used or stored. √  Water provides structural support to plants and makes plants turgid. √  Water regulates plant temperature and cools the plant. √  Water provides the medium for metabolic processes/for all biochemical processes. √ (Any 3) (3) 2.1.2 Adaptations of plants to reduce excessive water loss  Some leaves of plants have thick cuticles √  Some leaves have small, sunken stomata √  Some leaves are hairy (trichomes) √  Some leaves have small surfaces (pinnas) √ (Any 2 x 1) (2) 2.1.3 Part of plant for water and nutrient absorption Root hairs √ (1) 2.1.4 Transpiration pull Upward pulling force exerted on the water column in plants √ when water is lost during transpiration √ (2) Osmotic flow Movement of water through cells due to osmosis √ caused by an osmotic gradient √ (2) 2.2.1 Processes of the dark phase of photosynthesis  Chemical energy is used to reduce CO2 to glucose in the calvin cycle. √  The reaction of the dark phase occur in the stroma of a chloroplast. √  The dark phase is controlled by enzymes and therefore affected by temperature √  NADPH2 which is formed during the light phase releases  Hydrogen atoms and ATP releases excess energy it carries. √  The hydrogen atoms and the liberated react with CO2 taken up during photosynthesis to synthesise carbohydrates. √  Starches are synthesised through the withdrawal of water molecules from the glucose molecules. √  Glucose molecules combine with nitrate and sulphate ions and converted through enzymes to form plant proteins. √ (Any 3 x 1) (3) Copyright reserved Please turn over

Downloaded from hlayiso.com 4 AGRICULTURAL SCIENCES P2 (NOVEMBER 2014) 2.2.2 Importance of photosynthesis to human beings  It converts radiant energy from the sun to chemical energy. √  Stored sugars such as carbohydrates are used by organisms such as human beings. √  Produces oxygen which is needed for cellular respiration by all living organisms. √  The extraction of CO2 from the atmosphere keeps the atmosphere clean and maintains a healthy environment. √  It is the origin of fossilised fuels such as coal and petrol. √  It traps the energy for bio fuels which are produced from plants to replace fossil fuels and limit global warming. √ (Any 3 x 1) (3) 2.2.3 Ways to increase the rate of photosynthesis  Trellising to ensure that the fruit-bearing shoots have maximum exposure to sunlight for photosynthesis. √  Pruning to avoid overshadowing and to give leaves and fruit- bearing shoots maximum exposure to sunlight for photosynthesis. √  Spacing of crops to give leaves maximum light exposure. √  Green-houses to allow plants to obtain maximum exposure through transparent roofs. √ (Any 2 x 1) (2) 2.3.1 Micro nutrients Macro nutrients Boron √ Potassium √ Zinc √ Nitrogen √ (4) 2.3.2 Functions of boron  Increases the uptake of water and calcium. √  Essential for meristerm activity and growth of the pollen tube. √  Involved in the translocation of carbohydrates. √ (Any 1) (1) 2.3.3 Ways of mineral nutrients uptake by plants  Passive ion uptake by diffusion. √  Active ion uptake by transport carrier molecules √ (2) Copyright reserved Please turn over

Downloaded from hlayiso.com (NOVEMBER 2014) AGRICULTURAL SCIENCES P2 5 2.4 2.4.1 Reasons for the use of organic fertilisers  Organic matter helps the soil to hold water especially in sandy soil. √  Organic matter helps extra water to drain from clayey soil. √  Organic matter helps to cool the soil in summer and to warm it in winter/it absorbs heat during the day and emits heat in the night. √  Organic matter stops the soil from becoming hard and compacted. √  Organic matter helps to improve aeration in the soil. √  Organic matter binds the soil so that it is not eroded by wind or water. √  Organic matter nutrients have lasting effect on the soil. √  Organic matter improves the cat ion exchange capacity of the soil. √ (Any 3 x 1) (3) 2.4.2 Characteristics of crops used for green manuring  The seeds should be easily obtained. √  The crop should grow rapidly. √  It should have deeper root system in order to retrieve nutrients from deeper zones, thus making these available in the top soil √  It should be a strong feeder and be able to utilise some of the slowly available reserve nutrients. √  Legumes are generally used as they are able to fix nitrogen gas. √  It should have a high fibre content. √ (Any 3 x 1) (3) 2.5 2.5.1 Calculation of percentage of phosphorus in the mixture Nitrogen: 3 Phosphorus: 2 Potassium: 5 Total % of all 3 nutrients 45 3 + 2 + 5 = 10 √ P = 2/10 x 45 √ = 9% √ (3) 2.6 Uses of gypsum to grain farmers  It decreases the bulk density of the soil making it easier to till. √  It prevents crusting of soil and aids seed emergence √  Gypsum prevents water logging √  It decreases the loss of nitrogen fertiliser to the atmosphere √  It helps plants to absorb nutrients √  It stops water run-off and erosion √  It improves soil structure. √  Gypsum corrects soil acidity √  Gypsum decreases heavy-metal toxicity in soils √  It keeps clay particles from adhering to roots, bulbs and tubers √  It helps earthworms to flourish and improves soil aeration √ (Any 1) (1) [35] Copyright reserved Please turn over

Downloaded from hlayiso.com 6 AGRICULTURAL SCIENCES P2 (NOVEMBER 2014) QUESTION 3: PLANT REPRODUCTION 3.1 3.1.1 Pollination √ (1) 3.1.2 Water √ wind √ (2) 3.1.3 Cross pollination/Pollination When pollen is transferred from the anther of a flower on one plant √ to the stigma of a flower on another plant √ of the same species. √ OR Transfer of pollen grains from ripe anther √ to ripe stigma of a flower √ of the same species. √ (3) 3.2 3.2.1 Insect pest in 3.2.1 Lesser grain borer/grain borer (1) 3.2.2 Insect-management methods to prevent stored grains infestation  Sanitation – clean-up of old grain and grain debris √  Empty-bin spray with an insecticide √  Empty-bin fumigation, primarily to control insects in the subfloor space √  Storing only clean, dry grain √  Treating grain with a protecting insecticide √  Aeration to cool the grain to prevent insect feeding and reproduction √  Regular measurement of grain temperature and sampling for insects √ (Any 3 x 1) (3) 3.2.3 Ideal temperature for life cycle in 3.2 25 °C – 32 °C √ (1) 3.2.4 Implications of heavy pest infestation in stored grains  Severe stored grain infestation will lead to food shortages √  Price of grain crops on the local market will go up √  Foreign exchange of agricultural crops will decrease √  Control of the insects will be expensive. √  It would affect food security in the country √  It could demotivate potential grain farmers √ (Any 3 x 1) (3) 3.3 3.3.1 Natural methods Artificial methods Corms √ Layering √ Stolons √ Budding √ (4) Copyright reserved Please turn over

Downloaded from hlayiso.com (NOVEMBER 2014) AGRICULTURAL SCIENCES P2 7 3.3.2 Advantages of vegetative propagation  It is necessary for crops that cannot be propagated by seeds e.g. banana and sugar cane √  Plants propagated by asexual means are true to type √  It is a very quick method of reproduction √  Plants propagated by vegetative methods produce flowers and Fruits much earlier than seed produced plants √ (Any 2 x 1) (2) 3.4 3.4.1 Important characteristics of GMO crops  Resistance and tolerance to diseases √  Resistance to herbicides √  Increased tolerance to drought and low moisture √  Increased water use efficiency, they are able to produce more Yield with less water √  Increased fertiliser use efficiency √  They produce high yields √  They are more nutritious √  They have better keeping quality √ (Any 3 x 1) (3) 3.5 3.5.1 One name for the group of organisms Bacteria √ (1) 3.5.2 Measures to prevent the spread of bacteria in plants  Only use disease-free plant material such as seeds and - seedlings √  Buy certified seeds from well-known companies √  Sterilise water resources to make sure the water is free of diseases √  Destroy weeds and pathogens in the top soil layers by heat treatment √  Use chemicals like fungicides to eliminate inoculums √  Use sterile equipment √  Introduce good crop rotation programmes resistant crop varieties √ (Any 3 x 1) (3) 3.6.1 Ways weeds compete with crops on a farm  For space √  For sunlight √  For soil nutrients √ (3) 3.6.2 Other ways weeds compete with crops  Soil water/moisture √  For air √ (Any 1) (1) Copyright reserved Please turn over

Downloaded from hlayiso.com 8 AGRICULTURAL SCIENCES P2 (NOVEMBER 2014) 3.6.3 Chemical weed control It involves the use or application of chemical substances/ herbicides √ to kill/eliminate weeds or suppress plant growth by altering their metabolic processes. √ (2) Mechanical weed control It involves removing weeds physically, √ either by hand or with tools or machinery. √ (2) [35] QUESTION 4: OPTIMAL RESOURCES 4.1 4.1.1 Explanation of soil survey It is the process of classifying soil types and their distinctive properties/differentiating soil types from one another in a given area, √ and geo-encoding such information/interpreting and implementing the information. √ (2) 4.1.2 Aims of soil survey  For the suitability for a particular crop √  Suitability for irrigation  Suitability for animal grazing purposes √  To prevent erosion risk √  Identification for major agricultural land use e.g. gravel and marshy land √ (Any 2 x 1) (2) 4.1.3 Steps to follow in the physical analysis of soil.  Digging soil pits √  Determining soil profile √  Determining physical and chemical properties √ (3) 4.2 4.2.1 Type of farming in fig 4.2 Precision farming √ (1) 4.2.2 Aims of the method of the type of farming in QUESTION 4.2.1  To minimise inputs. √  Maximise yields. √  To use sustainable practices such as pest, water and nutrient management. √  Reduces environmental risk of farming through accurate application of inputs e.g. limiting leaching. √  For effective management √ (Any 3 x 1) (3) Copyright reserved Please turn over

Downloaded from hlayiso.com (NOVEMBER 2014) AGRICULTURAL SCIENCES P2 9 4.3 4.3.1 Irrigation It is the application of water to the soil or any growth medium √ for the purpose of benefiting the plant √ (2) Drainage It is the removal of standing or excess water √ from the surface and subsurface of a poorly drained soil. √ (2) (4) 4.3.2 Criteria to determine the water quality for irrigation  Check the pH of the water and the pH of the soil √  Determine specific electrical conductivity of water √  Determine the sodium adsorption ratio/sodality of the water should be determined √ (3) 4.3.3 Factors to consider when planning and applying an irrigation method  Quantity of water available √  Topography of the area to irrigate √  Infiltration tempo of the soil/texture and structure of the soil√  Type of crop to be grown on the field √  Method of cultivation to be used √  Installation cost √ (Any 2 x 1) (2) 4.4 4.4.1 Cropping system in QUESTION 4.4 Crop rotation √ (1) 4.4.2 Justification of cropping system in question 4.4  Four different crops rotate over four growing seasons. √  Deep rooted crops like roots and tubers are followed by shallow rooted crops like alliums. √  Legumes are included to fix atmospheric nitrogen in the soil. √  The field is divided into four equal plots and each plot has the same plant species. √ (Any 1 x 1) (1) 4.4.3 Factors which play a fundamental role in planning the cropping system in question 4.4  Consider the climatic conditions in terms of rain and temperature √  The crop must be suited to that particular type of soil √  Sufficient labour must be available √  Determine the demand for the crop √  Ensure the availability of machinery √  Ensure competent management skills √  Know the family for the crop selection/include legumes √ (Any 2 x 1) (2) Copyright reserved Please turn over

Downloaded from hlayiso.com 10 AGRICULTURAL SCIENCES P2 (NOVEMBER 2014) 4.4.4 Benefits of the cropping system in QUESTION 4.4  It helps to combat diseases, weeds and insect pests by reducing their occurrence through changing host plants. √  Reduces reliance on synthetic chemicals thus contributing toward saving. √  Reduces soil nutrient depletion because different crops with different roots absorb nutrients from different soil dept. √  Maintains soil fertility e.g. legumes add nitrogen to the soil through nitrogen fixation √  Reduces soil erosion through growing crops which provide better soil cover and root system binding soil particles. √  Spreads the risk of total crop failure. √  Keeps the farmer and farm assistants competent in production and management skills involving many crops. √ (Any 2 x 1) (2) 4.5 4.5.1 Benefits of green house for production of high value cash crops  Optimal effectiveness in the utilisation of natural resources is achieved √  Optimal production output is possible. √  Better quality produce is achieved since insects/weeds and physical damage by wind can be totally eliminated. √  Better scale of economy is achieved/can produce all year round √  More effective √ utilisation of unsuitable agricultural land. √  Risk of crop loss is minimal as plants are protected against natural hazards. √  More pleasant working conditions than in open-fields. √ (Any 3 x 1) (3) 4.5.2 Hydroponics The process of growing plants in liquid, with added nutrients √ but without soil. √ (2) 4.5.3 Growth mediums that support plants in hydroponics systems  Pumice and perlite √  Vermiculite √  Expanded clay √  Coir/peat √  Wood fibre √  Peat moss √  Sawdust √  Straw bales √  Sand/gravel √  Water √ (Any 2 x 1) (2) Copyright reserved Please turn over

Downloaded from hlayiso.com (NOVEMBER 2014) AGRICULTURAL SCIENCES P2 11 4.5.4 Factors which may restrict farmers from choosing certain species for aquaculture  Geographic location √  Water supply √  Availability of capital √  Expertise and training √  Availability of services √  Market location √ (Any 2 x 1) (2) [35] TOTAL SECTION B: 105 GRAND TOTAL: 150 Copyright reserved Please turn over