Agricultural Sciences Grade 11 P1 2023 Memo (Eng)

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER 2023 AGRICULTURAL SCIENCES P1 MARKING GUIDELINE MARKS: 150 This marking guideline consists of 12 pages.

Downloaded from hlayiso.com 2 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2023) SECTION A QUESTION 1 1.1 1.1.1 B ✓✓ 1.1.2 C ✓✓ 1.1.3 A ✓✓ 1.1.4 D ✓✓ 1.1.5 C ✓✓ 1.1.6 D ✓✓ 1.1.7 A ✓✓ 1.1.8 C ✓✓ 1.1.9 B ✓✓ 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 A only ✓✓ 1.2.5 Both A and B ✓✓ (5 x 2) (10) 1.3 1.3.1 Molecule ✓✓ 1.3.2 Lewis structure ✓✓ 1.3.3 Clay ✓✓ 1.3.4 Porosity ✓✓ 1.3.5 Colloids ✓✓ (5 x 2) (10) 1.4 1.4.1 Simple ✓ 1.4.2 Saturation ✓ 1.4.3 Cation adsorption ✓ 1.4.4 Assimilation ✓ 1.4.5 Illuviation ✓ (5 x 1) (5) TOTAL SECTION A: 45 Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2023) AGRICULTURAL SCIENCES P1 3 SECTION B QUESTION 2: BASIC AGRICULTURAL CHEMISTRY 2.1 Bonding 2.1.1 Classification of compounds A – Inorganic ✓ (1) 2.1.2 Name of the elements A – Sodium ✓ (1) B – Chloride ✓ (1) 2.1.3 Explanation of ionic bonding It is a bonding where electrons are transferred ✓ from one atom to another. ✓ (2) 2.1.4 Indication of the charge of elements (a) Element B – Negatively charged ✓ (1) (b) Element A – Positively charged ✓ (1) 2.1.5 ONE importance of salt • It is an important part of the fluid electrolytes of living organisms ✓ • Used to preserve food ✓ • Inhibits the growth of bacteria ✓ • Used in the treatment of hides and skins ✓ • Acts as a flavour enhancer in food ✓ (Any 1 x 1) (1) 2.2 Acids and bases 2.2.1 Prediction of the pH in the mixture Neutral ✓ (1) 2.2.2 Indication of the substance (a) Base – NaOH ✓ (1) (b) Acidic – HCℓ ✓ (1) 2.2.3 TWO differences between acid/HCℓ and base/Na ACIDS/HCℓ BASE/NaOH • Donates hydrogen ions to water • Accepts hydrogen ion from molecules ✓ water molecules ✓ • Taste sour ✓ • Taste bitter ✓ • Turns litmus paper red ✓ • Turns litmus paper blue ✓ • High concentration of hydrogen • High concentration of ions (H+) ✓ hydroxide ions (OH-) ✓ (Any 2 x 2) (4) Copyright reserved Please turn over

Downloaded from hlayiso.com 4 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2023) 2.3 Organic compounds 2.3.1 Name of a compound Carbohydrates ✓ (1) 2.3.2 Identification of B – Unsaturated fats ✓ (1) C – Saturated fats ✓ (1) 2.3.3 Indication of the letter (a) Animal origin – C ✓ (1) (b) Liquid at room temperature – B ✓ (1) 2.3.4 TWO functions of carbohydrates • Source of energy for living organisms ✓ • Constituent of cell walls in plants ✓ • Fibre improves functioning of the digestive system ✓ • Contribute in cellular functions such as cell growth ✓ (Any 2 x 1) (2) 2.3.5 Chemical formula of disaccharides C12H22O11 ✓ (1) 2.4 Alcohols 2.4.1 Name of an alcohol Ethanol ✓ (1) 2.4.2 Structural formula of an ethanol H H H C C OH H H Marking criteria • Presence of 5 hydrogen ✓ • Presence of 2 carbons ✓ • Presence of OH ✓ (3) 2.4.3 ONE difference between alcohols and alkanes Alkanes consist of carbon and hydrogen atoms only ✓ and in alcohols one hydrogen atom is replaced by – OH ✓ (2) Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2023) AGRICULTURAL SCIENCES P1 5 2.5 Protein 2.5.1 Identification of the structure Amino acid ✓ (1) 2.5.2 Labelling A – Amino group ✓ (1) B – Carboxyl group ✓ (1) 2.5.3 Name of the polymer Protein ✓ (1) 2.5.4 TWO functions of the proteins • Important for growth and repair of muscles/bones ✓ • It forms enzymes and hormones needed for metabolism and important processes ✓ • Transport other substances in the body ✓ • Provide antibodies for the protection against infections ✓ • Used to build collagen/keratin in an organism ✓ (Any 2 x 1) (2) [35] Copyright reserved Please turn over

Downloaded from hlayiso.com 6 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2023) QUESTION 3: SOIL SCIENCE 3.1 Soil texture 3.1.1 Indication of the sample (a) Sample B ✓ (1) (b) Sample A ✓ (1) (c) Sample A ✓ (1) 3.1.2 Calculation of bulk density Mass (g) Bulk density = 3 ✓ Volume (cm ) 480 g = ✓ 460 cm3 = 1,04 g/cm3 ✓ (3 x 1) (3) 3.1.3 ONE reason of knowing the texture class of the soil • To adopt the crop production adapted to the characteristics of soil/ to make crop choices ✓ • To know when to cultivate and which implements to use ✓ • To be able to assess the efficacy of fertilisers ✓ • To know the type of irrigation to use ✓ • To understand how soil will react better to temperature changes ✓ (Any 1 x 1) (1) 3.2 Soil structure 3.2.1 Identification of the structure A – Platy ✓ (1) B – Prism-like/columnar/prismatic ✓ (1) C – Crumb/spheroid ✓ (1) 3.2.2 Indication of the letter representing the structure (a) A ✓ (1) (b) C ✓ (1) 3.2.3 TWO factors contributing to the development of structure • Activity of soil organisms/microbial gum ✓ • Alternate moisture and drought ✓ • Type of clay mineral present ✓ • Colloidal matter in the soil/clay/organic matter content ✓ • Climate ✓ • Plant roots ✓ (Any 2 x 1) (2) Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2023) AGRICULTURAL SCIENCES P1 7 3.3 Soil moisture 3.3.1 Indication of the water movement Capillary movement ✓ (1) 3.3.2 TWO forces that have an effect on capillary movement • Adhesion ✓ • Cohesion ✓ (2) 3.3.3 Identification of soils (a) C – Clay ✓ (1) (b) A – Sand ✓ (1) 3.3.4 Reason (a) Highest water level in soil C – Particles are close together and capillarity forces are stronger ✓ (1) (b) Lowest water level in soil A – Many of the pores are too large and low capillarity ✓ (1) 3.4 Soil colour Indication of soil condition regarding moisture and air: (a) Red colour: Enough air ✓ and low moisture ✓ (2) (b) Grey colour: Waterlogged conditions ✓ and absence of air ✓ (2) Copyright reserved Please turn over

Downloaded from hlayiso.com 8 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2023) 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 Comparing atmospheric gases and soil gases in experiment 2 and experiment 1 (a) Experiment 2 – Soil air contains much more carbon dioxide ✓ than atmospheric air ✓ (2) (b) Experiment 1 – Soil air contains less oxygen ✓ than atmospheric air ✓ (2) 3.6 Soil temperature 3.6.1 Identification of the factor influencing the soil temperature Soil depth ✓ (1) 3.6.2 Explanation of how soil depth has an influence on soil temperature Soil temperature variation decreases ✓ with an increase in soil depth ✓ (2) 3.6.3 ONE effect of soil temperature on the chemical processes in soil • Faster chemical reactions in the soil ✓ • More nutrients are released ✓ • At high temperatures soil water dissolve more plant nutrients ✓ (Any 1 x 1) (1) [35] Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2023) AGRICULTURAL SCIENCES P1 9 QUESTION 4: SOIL SCIENCE 4.1 Soil horizons 4.1.1 Letter representing a horizon (a) Partly weathered material – H ✓ (1) (b) Consolidated rock – I ✓ (1) (c) Partly decomposed organic matter – E ✓ (1) 4.1.2 Indification of J – Soil profile ✓ (1) 4.1.3 Sketching the soil profile O A ✓✓ B C R (2) 4.1.4 TWO diagnostic horizons of A horizon • Humic ✓ • Vertic ✓ • Melanic ✓ • Orthic ✓ (Any 2 x 1) (2) 4.2 Soil classification 4.2.1 TWO 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 2 x 1) (2) 4.2.2 System used in South Africa to classify soil Binomial system ✓ (1) Copyright reserved Please turn over

Downloaded from hlayiso.com 10 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2023) 4.3 Soil pH 4.3.1 Line graph Criteria/rubric/marking guideline • Correct heading ✓ • X-axis: Correctly calibrated and labelled (Soil pH) ✓ • Y-axis: Correctly calibrated and labelled (Availability of phosphorus) ✓ • Line graph ✓ • Accuracy ✓ (80% or more correct plot(ting) • Correct unit (g) ✓ (6) 4.3.2 Deduction of the influence of acidity and alkalinity on the availability of phosphorus. In acid soil/low pH phosphorus is less available ✓ In alkaline soil /high pH phosphorus is more available ✓ (2) 4.3.3 Chemical substance to be applied to solve. (a) Decreased availability of phosphorus in soils with a pH of between 2 and 4 Application of basic fertilisers such as lime/CaCO3 ✓ (1) (b) Toxic quantities of phosphorus in soil with pH of 14 Application of gypsum/CaSO4 ✓ (1) Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2023) AGRICULTURAL SCIENCES P1 11 4.4 Soil colloid 4.4.1 Deduction of the term applicable to the process B – Cation exchange ✓ (1) 4.4.2 Reason for cation exchange Potassium cation from the soil solution exchange with the hydrogen adsorbed in the colloid ✓ (1) 4.4.3 Type of acidity A – Reserve acidity ✓ (1) B – Active acidity ✓ (1) 4.4.4 Identification of cation Na+ ✓ (1) 4.4.5 TWO effects of sodicity on plant growth • Hydrolysis of sodium in soil solution causes the pH to rise above 8,5 ✓ • Has a deflocculating effect on soil colloids causing the soil to become structureless ✓ • Humus dissolves in the soil and precipitates in the upper soil horizon ✓ • Leads to the development of a prismatic soil structure ✓ • Leads to poor seed germination ✓ • High concentration makes it difficult for plants to absorb water ✓ (Any 2 x 1) (2) 4.5 Soil organisms 4.5.1 Classification of soil organisms Micro-organisms ✓ (1) 4.5.2 TWO importance of soil organisms • They break down/decompose plant and animal remains to release plant nutrients ✓ • Bind nitrogen in the atmosphere in the form of ammonium salts/ Play an important role in the nutrient cycling ✓ • Secrete substances to stimulate plant growth ✓ • Secrete sticky substance that glue soil particles to form aggregates ✓ • Degrade many harmful chemicals in the soil ✓ (Any 2 x 1) (2) Copyright reserved Please turn over

Downloaded from hlayiso.com 12 AGRICULTURAL SCIENCES P1 (EC/NOVEMBER 2023) 4.5.3 TWO requirements 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 x 1) (2) 4.6 Organic matter TWO factors that lower the organic matter content on soil • Tillage of soil ✓ • Type of plant ✓ • Monoculture ✓ • Use of artificial fertilisers ✓ • Climate ✓ • Poor veld management and burning ✓ • Poor drainage ✓ • Climate ✓ (Any 2 x 1) (2) [35] TOTAL SECTION B: 105 GRAND TOTAL: 150 Copyright reserved Please turn over