STUDY GUIDE AGRICULTURAL SCIENCES GRADE 11 A publication of Impak Onderwysdiens (Pty) Ltd Copyright reserved. Apart from any fair dealing for the purpose of research, criticism or review as permitted under the Copyright Act, no part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, without permission in writing from Impak Onderwysdiens (Pty) Ltd. CAPS aligned Compiler JC Zandberg Ë1511-E-AGS-SG01 µ Î
TABLE OF CONTENTS PREFACE... 3 YEAR PLAN... 4 UNIT 1: Basic agricultural chemistry... 7 Lesson 1: Basic agricultural chemistry... 7 ACTIVITY 1:... 16 Lesson 2: Chemical bonding... 17 ACTIVITY 2... 20 Lesson 3: Inorganic and organic compounds... 20 ACTIVITY 3... 25 Lesson 4: Alkanes and alcohol... 25 ACTIVITY 4... 28 Lesson 5: Fatty acids and bio-molecules... 29 ACTIVITY 5... 32 Lesson 6: Proteins... 33 ACTIVITY 6... 36 Lesson 7: Carbohydrates... 36 ACTIVITY 7... 41 Lesson 8: Soil science and texture... 42 ACTIVITY 8... 54 Lesson 9: Soil structure... 55 ACTIVITY 9... 63 Lesson 10: Soil colour and soil pores... 64 ACTIVITY 10... 76 UNIT 2: Soil science... 77 Lesson 11: Soil air... 77 ACTIVITY 11... 82 Lesson 12: Soil moisture... 82 ACTIVITY 12... 102 Lesson 13: Soil temperature... 103 ACTIVITY 13... 111 Lesson 14: Soil morphology... 112 ACTIVITY 14... 120 Lesson 15: Soil classification... 120 ACTIVITY 15... 129 Lesson 16: Soil colloids and soil acidity... 129 ACTIVITY 16... 145 Lesson 17: Soil alkalinity en salinity... 146 ACTIVITY 17... 150 Impak Onderwysdiens (Pty) Ltd 1
UNIT 3: Soil... 151 Lesson 18: Soil organic matter... 151 ACTIVITY 18... 158 Lesson 19: Soil non-living organic matter... 158 ACTIVITY 19... 161 Lesson 20: Plant nutrition: Photosynthesis... 162 ACTIVITY 20... 172 Lesson 21: Water and nutrients... 173 ACTIVITY 21... 180 Lesson 22: Mineral nutrition... 181 ACTIVITY 22... 188 Lesson 23: Plant nutrient uptake and analysis... 188 ACTIVITY 23... 196 Lesson 24: Organic and inorganic fertilisers... 197 ACTIVITY 24... 203 Lesson 25: Organic fertilisers... 203 ACTIVITY 25... 214 Lesson 26: Plant reproduction... 215 ACTIVITY 26... 221 Lesson 27: Fertilisation and ablactation... 221 ACTIVITY 27... 228 UNIT 4: Plant reproduction... 229 Lesson 28: Plant reproduction... 229 ACTIVITY 28... 239 Lesson 29: Plant improvement and biotechnology... 239 ACTIVITY 29... 246 Lesson 30: Plant pests/parasites and diseases... 246 ACTIVITY 30... 251 Lesson 31: Plant diseases/pests and control... 251 ACTIVITY 31... 259 Lesson 32: Optimal resource... 259 ACTIVITY 32... 268 Lesson 33: Soil drainage systems, soil cultivation and crop rotation... 269 ACTIVITY 33... 280 Lesson 34: Greenhouse, hydroponics and aquaculture... 280 ACTIVITY 34... 291 BIBLIOGRAPHY... 292 Impak Onderwysdiens (Pty) Ltd 2
Unit 1 UNIT 1: Basic agricultural chemistry LEARNING AIMS: After you have completed this unit, you must be able to: Identify the differences between elements, compounds and mixture. The differences between acids and bases. The general structure of an atom. The main types of particles of an atom and their respective charges. The relation between atomic numbers and number of particles in the nucleus. INTRODUCTION This section begins with chemical analysis in agriculture and leads up to soil in particular. It is important to keep the bigger picture in mind right through the course of this term. Each structure is broken down to the smallest detail and is later reassembled. Lesson 1: Basic agricultural chemistry IMPORTANT TERMINOLOGY Atoms: The smallest building blocks that makes up everything around us. Molecules: A neutral group of two or more atoms tied together, strong enough to act as a separate unit in a chemical reaction. Periodic table: Elements are arranged according to their chemical and physical properties. Isotopes: Atoms with the same quantity of atoms, but different masses. Impak Onderwysdiens (Pty) Ltd 7
Unit 1 The difference between elements, compounds and solutions DEFINE: Elements: An element is a pure substance. Elements contain only one type of atom and therefore can t be broken down into smaller substances. Compounds: A compound is formed when two or more elements connect to each other chemically in a strong connection. Solutions: Pure homogeneous mixtures of substances which are present in the same phase and consist of two or more substances in the same phase. An element cannot be fractioned into a simpler material by chemical methods, while is compound is built from more than one element. For example, hydrogen (H2) consists out of two hydrogen atoms. Compounds are formed when the atoms of two or more elements are combined. It does not matter how the compound is made, it will always consist of the same elements in the same mass ratio. Most of the substances we come into contact with on a daily basis are not pure, but are mixtures. Air is a mixture of gasses and soil a mixture of many substances. We distinguish between various types of mixtures: Homogeneous mixtures are mixtures where it cannot be distinguished between sugar- and water particles in, for example, a sugar solution. Heterogeneous mixtures are mixtures where it can be clearly distinguished between the different components of a mixture, for example a mixture of sand and sugar. Solutions can be described as pure homogenous mixtures of substances, which are present in the same phase. Mixtures differ from compounds as the ingredients of a mixture can be separated by simple physical methods like filtration, diffusion and distillation. However, the ingredients of a compound cannot be separated physically. The ratio of the ingredients of a mixture can also be altered easily, while that of a compound is fixed and cannot be altered by physical means. Water is one of the most effective solvents. The water molecule is formed through covalent bonding. The molecule experiences a small negative charge on the oxygen side, while the area where we find the hydrogen atoms shows a small positive charge. This molecule is known as a polar molecule, as the molecule has a slightly negative pole and a slightly positive pole. Impak Onderwysdiens (Pty) Ltd 8
Unit 1 The following table shows the main characteristics of elements, compounds and solutions: ELEMENT COMPOUND SOLUTION (MIXTURES) Pure substance Pure substance Impure substance Consists of one type of atom A chemical combination of two or more elements A physical combination of two or more elements Consists of one type of atom Elements in the compound connect in a strong connection Quantities of substances in a mixture can vary Can t be separated Can only be separated by chemical methods Can be separated by physical methods Has own, unique properties (Lucas et al., 2007) Properties of the compound is different to the properties of the elements Substances in the mixture retain their unique properties The basic interpretation of the periodic table of elements Elements are arranged according to their chemical and physical properties on the period table. There are two sets of columns: the horizontal and the vertical. The horizontal columns are read from left to right. These are called periods. There are seven periods, numbered in Arabic numerals (1,2,3 etc.) The vertical columns are read from top to bottom. These are called groups and are numbered in Roman numerals. There are eight groups, for example IA or IIB. Each element is represented by a letter or a few letters. The symbol for the element is usually an abbreviation of its Latin name, for example Ca for calcium or O for oxygen. The two digits that accompany the symbol are descriptions of some properties. The important digit is the atom number. It is usually above the symbol and indicates the quantity of protons in a nucleus. As most atoms have a neutral electric charge and protons are positive, the same quantity of negative charges are needed to establish neutrality. As a result, the atom number is an indication of the quantity of electrons around an atom s nucleus. The second digit is the mass number and is the sum of the protons and neutrons in a nucleus and an indication of an atom s mass. Elements are arranged numerically according to their atom numbers, for example hydrogen (1) first, followed by helium (2) etc., so the arrangement is from smallest to largest. Impak Onderwysdiens (Pty) Ltd 9