Agricultural Sciences Grade 11 P1 2020 Memo (Eng)

NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER 2020 AGRICULTURAL SCIENCES P1 MARKING GUIDELINE (EXEMPLAR) MARKS: 150 This marking guideline consists of 9 pages.

2 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2020) SECTION A QUESTION 1 1.1 1.1.1 C  1.1.2 D  1.1.3 C  1.1.4 A  1.1.5 C  1.1.6 D  1.1.7 A  1.1.8 B  1.1.9 D  1.1.10 B  (10 x 2) (20) 1.2 1.2.1 B only  1.2.2 A only  1.2.3 None  1.2.4 B only  1.2.5 Both A and B  (5 x 2) (10) 1.3 1.3.1 Halogen  1.3.2 Lewis structure  1.3.3 Loam  1.3.4 Nitrogen  1.3.5 Colloid  (5 x 2) (10) 1.4 1.4.1 Cation  1.4.2 Hygroscopic  1.4.3 Acid  1.4.4 Mycorrhiza  1.4.5 Illuviation  (5 x 1) (5) TOTAL SECTION A: 45 Copyright reserved Please turn over

(EC/NOVEMBER 2020) AGRICULTURAL SCIENCES P1 3 SECTION B QUESTION 2: BASIC AGRICULTURAL CHEMISTRY 2.1 Compounds 2.1.1 Classification of compounds A – Organic  B – Inorganic  (2) 2.1.2 Reason A – Presence of carbon atom  B – Absence of carbon atom  (2) 2.1.3 Name of compounds with the same molecular formula but different structure Isomers  (1) 2.1.4 Chemical formula of a compound represented by structure A  C4H10  OR  CH3 (CH2)2 CH3  (2) 2.1.5 Identification of the letter (a) C  (b) B  (2) 2.2 Matter/elements/compounds/mixtures 2.2.1 Identification of substances A – Compound  B – Homogeneous mixture  C – Heterogeneous mixture  (3) 2.2.2 Difference between an element and a compound Element is a substance that cannot be broken down by chemical means  Compound is a substance formed when two or more elements are chemically combined  (2) 2.2.3 Distinguishing between homogeneous and heterogeneous mixtures Homogeneous – mixture in which the dissolved solute cannot be separated from the solvent by physical means  Heterogeneous – mixture in which the components can be separated by physical means  (2) Copyright reserved Please turn over

4 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2020) 2.3 Fatty acids 2.3.1 Identification of the fatty acid A – Unsaturated fatty acid  B – Saturated fatty acid  (2) 2.3.2 Indication of the letter representing the fatty acid (a) Originating from plants – A (b) Solid at room temperature – B  (c) Has a high melting point – B  (d) Liquid at room temperature – A  (4) 2.3.3 TWO importance of fats in living organisms  Provide a source of stored energy   Source of insulation and temperature control   Vital part of membrane structure   Play a role in the flow of energy in and out of living cells   Assist in signal transduction  (Any 2) (2) 2.4 pH values 2.4.1 Indicating the pH of substances Baking powder – Alkaline  Orange juice – Acidic  Milk – Neutral  Battery acid – Strongly acidic  (4) 2.4.2 Indicating the substance with a high concentration of (a) Hydroxide ion – Baking powder  (b) Hydrogen ion – Battery acid  (2) 2.5 Monosaccharide 2.5.1 Names of the structures A – Fructose  B – Glucose  (2) 2.5.2 Indication of the compound formed from fructose and glucose Sucrose  (1) 2.5.3 TWO elements that are basic composition of carbohydrates  Carbon   Hydrogen   Oxygen  (Any 2) (2) [35] Copyright reserved Please turn over

(EC/NOVEMBER 2020) AGRICULTURAL SCIENCES P1 5 QUESTION 3: SOIL SCIENCE 3.1 Soil texture 3.1.1 Indication of the sample (a) Sample B  (b) Sample A  (c) Sample B  (d) Sample A  (4) 3.1.2 Commenting on the pore space of soil sample B by referring to bulk density Soil sample B has a high bulk density / 3,2 g/cm3 and therefore lower pore space  (2) 3.2 Soil structure 3.2.1 Identification of the structure A – Platy  B – Prism-like/columnar/prismatic  C – Crumb/spheroid  (3) 3.2.2 Indicating the letter representing the structure (a) A  (b) C  (2) 3.2.3 TWO malpractices leading to the destruction of structure  Flood irrigation   Cultivation of soil when it is too dry or wet   Ploughing and other tilling methods   Overgrazing / burning / removal of plant material   Movement of animals and equipment over wet soil   Irrigation leading to salt accumulation  (Any 2) (2) 3.3 Soil moisture 3.3.1 Naming the term A – Saturation point  B – Field water capacity  (2) 3.3.2 Reason A – Soil is completely filled with water  B – Amount of water held in soil after saturation and drainage  (2) 3.3.3 Plant response grown in soils in Container C and D (a) B – Plants will grow optimally  (b) C – Plants will wither/die  (2) 3.3.4 Differentiation between temporal and permanent wilting points Temporal wilting – The point when plants appear wilted only during the hottest part of the day and recover  Permanent wilting – Plants do not recover from wilting  (2) Copyright reserved Please turn over

6 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2020) 3.4 Soil colour 3.4.1 Differentiation between homogeneous and non-homogeneous soil colour Homogeneous – Single dominant colour in soil  Non-homogeneous – Mixture of soil colours  (2) 3.4.2 TWO factors determining the colour of soil  Presence of water   Gleying conditions   Organic material   Presence of oxides   Presence of carbonates  (Any 2) (2) 3.5 Soil gas 3.5.1 Indication of the gas deficient in experiment 1 Oxygen  (1) 3.5.2 Role the gas could have played if not deficient Influenced seed germination  (1) 3.5.3 Gas high in soil as a result of activities in experiment 2 Carbon dioxide  (1) 3.5.4 Reason for the high amount of carbon dioxide Released during respiration  of plant roots and soil micro-organisms  (2) 3.6 Soil temperature 3.6.1 Indication of the letter (a) A  (b) C  (c) A  (3) 3.6.2 TWO methods to manipulate soil temperature  Irrigation   Mulching   Clear plastic covers   Shading  (Any 2) (2) [35] Copyright reserved Please turn over

(EC/NOVEMBER 2020) AGRICULTURAL SCIENCES P1 7 QUESTION 4: Soil science 4.1 Soil horizons 4.1.1 Sketching the soil profile A B  C R (2) 4.1.2 Indication of the horizon (a) E  (b) G  (2) 4.1.3 TWO diagnostic horizons of A horizon  Humic   Vertic   Melanic   Orthic  (Any 2) (2) 4.2 Soil classification 4.2.1 THREE reasons for classification of soil  Optimal utilisation of country’s natural resources   Scientific planning of farm   Determining the crop production potential of the soil   Improved soil science communication   Development of new regions   Valuation of soils  (Any 3) (3) 4.2.2 System used in South Africa to classify soil Binomial system  (1) Copyright reserved Please turn over

8 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2020) 4.3 Soil pH 4.3.1 Line graph Effect of soil pH on availability of Molybdenum Availability of Molybdenum (g) 16 14 12 10 8 6 4 2 0 2 4 6 8 10 12 Soil pH Criteria/rubric/marking guideline  Correct heading   X-axis: Correctly calibrated and labelled (Soil pH)   Y-axis: Correctly calibrated and labelled (Availability of molybdenum)   Line graph   Accuracy   Correct unit (g)  (6) 4.3.2 Deduction of the influence of acidity and alkalinity on the availability of molybdenum In acid soil/low pH molybdenum is not available  In alkaline soil / high pH molybdenum is more available  (2) 4.3.3 Measures to solve problems of: (a) Decreased availability of molybdenum in soils with a pH of between 2 and 4 Application of basic fertilisers such as lime/CaCO3  (1) (b) Toxic quantities of molybdenum in soil with pH of 14 Application of gypsum/CaSO4  (1) 4.4 Soil colloid 4.4.1 Deduction of the process A – Cation adsorption  B – Cation exchange  (2) 4.4.2 Reason for cation exchange Potassium cation from the soil solution exchanges with the hydrogen adsorbed in the colloid  (1) Copyright reserved Please turn over

(EC/NOVEMBER 2020) AGRICULTURAL SCIENCES P1 9 4.4.3 Indication of the hydrogen cation having an effect on plants Hydrogen in the soil solution  (1) 4.4.4 TWO types of colloids Organic colloid Inorganic colloid  (2) 4.4.5 Differentiation between sodic and saline soils with regard to dominant salts Sodic soil – Sodium carbonates  Saline soil – Chlorides and sulphates of sodium, calcium and magnesium  (2) 4.5 Soil organisms 4.5.1 Classification of the worms into groups of soil organisms Macro-organisms  (1) 4.5.2 TWO conditions for the survival of worms  Organic nutrients   Mineral nutrients (nitrogen/phosphorus/potassium)   Soil moisture close to field water capacity   Soil air for respiration  Optimum temperature (temperature between 25 °C and 30 °C   Optimum soil pH  (Any 2) (2) 4.5.3 Explanation of how worms will assist farmers  Break down plant and animal remains  to liberate plant nutrients   Improve soil structure  for increased water retention capacity   Worm casts is rich in organic matter  which improves soil fertility   Maintain CO2 concentration  which is used by plants during photosynthesis  (Any 1) (2) 4.6 Nutrient cycle Nutrient cycle increasing nutrient content in plants (a) Protein content – Nitrogen cycle  (1) (b) Carbohydrate content – Carbon cycle  (1) [35] TOTAL SECTION B: 105 GRAND TOTAL: 150 Copyright reserved Please turn over