Agriculture 0600 | Paper 2 Mock 01 | Component: Practical Coursework

(a) The process by which mineral salts enter root hair cells from the soil solution is active transport. [1] This requires energy from cellular respiration because minerals are moved against their concentration gradient (from a lower concentration in the soil solution to a higher concentration inside the cell).

(b) Two mineral elements that the yellowing plants are most likely lacking:

1. Nitrogen - essential for making amino acids, proteins, and chlorophyll. Deficiency causes general yellowing (chlorosis) of older leaves first, as nitrogen is mobile and redistributed to younger growth. [1]
2. Magnesium - a central atom in the chlorophyll molecule. Deficiency causes yellowing between the leaf veins (interveinal chlorosis). [1]

Other acceptable answers: iron or sulphur, both of which are involved in chlorophyll synthesis or function.

(c) How water moves from the soil into the root hair cell:

1. The soil solution has a higher water concentration (higher water potential) than the cell sap inside the root hair cell's vacuole, which contains dissolved sugars and salts. [1]
2. Water moves by osmosis - the net movement of water molecules from a region of higher water potential to a region of lower water potential. [1]
3. This movement occurs through the partially permeable cell membrane, which allows water molecules to pass but restricts larger solute molecules. [1]

(d) One reason plants on one side of the field may have received fewer minerals: the soil on that side may be more sandy, causing nutrients to leach away more quickly with drainage water. [1] Other acceptable reasons: uneven distribution of fertiliser during application; the previous crop on that side removed more nutrients; or drainage patterns differ across the field.

(e) To correct the yellowing, the farmer should:

1. Apply a nitrogenous fertiliser or top-dress with a compound fertiliser containing nitrogen and magnesium to replace the deficient elements. [1]
2. Apply as a foliar spray for faster uptake through the leaves, or apply to the soil around the affected plants and water in. [1]

Foliar application is faster-acting because nutrients are absorbed directly through the leaf epidermis, bypassing the slower root uptake pathway.

(a) Site Y has a deeper topsoil layer, at 45 cm compared to 12 cm at Site X [1].

(b) Two reasons why the topsoil at Site Y is deeper than at Site X:

1. Soil eroded from the steep hillside (Site X) is carried downhill by surface runoff and deposited in the flat valley (Site Y), where it accumulates over time [1].
2. Less erosion occurs on flat land because water flows more slowly across the surface, so soil particles are not removed as rapidly as they are on the slope [1].

Other acceptable reasons: water drains more slowly on flat land, allowing more weathering and organic matter accumulation.

(c) Water moving through the soil at Site X affects the mineral content of the topsoil in the following way:

1. Water percolating through the soil dissolves soluble minerals (such as calcium, magnesium, and potassium) from the topsoil [1].
2. These dissolved minerals are carried downwards by the water into the subsoil or lower horizons [1].
3. Over time, this process depletes the mineral content and fertility of the topsoil, leaving it nutrient-poor [1].

(d) The process by which soluble minerals are carried downwards through the soil by water is called leaching [1]. Leaching is particularly rapid on slopes where rainfall is high and the soil is well-drained.

Labelled answer diagram:

(a) Parts of the pig digestive tract [3]

1. P - Oesophagus (gullet): the muscular tube that conveys swallowed food from the mouth to the stomach by peristalsis. [1]
2. Q - Stomach: the sac-like organ where hydrochloric acid and pepsin begin chemical digestion of proteins. [1]
3. R - Small intestine: the long, coiled tube where most chemical digestion and nutrient absorption occur, aided by enzymes from the pancreas and bile from the liver. [1]

(b) Main site of protein digestion in the pig [1]

The stomach (where pepsin begins breaking polypeptide chains) and especially the small intestine (where pancreatic trypsin and chymotrypsin complete digestion to amino acids). [1]

(c) Two concentrate feeds used in pig rations [2]

Any two of:

1. Maize (corn) - a high-energy cereal grain that forms the base of most pig rations. [1]
2. Soybean meal (or groundnut cake) - a protein-rich supplement to balance the cereal energy. [1]
3. Wheat, barley, or sorghum - alternative cereal grains.
4. Fish meal - a high-quality animal protein source.
5. Palm kernel cake - a by-product protein source.

(d) Why pigs need more concentrate feed than cattle [2]

1. Pigs are monogastric animals with a simple stomach and cannot digest large amounts of fibre or cellulose, because they lack the rumen microorganisms that produce cellulase. [1]
2. They therefore depend on energy-dense, protein-rich concentrate feeds (grains, oilseed meals) to meet their nutritional requirements for rapid growth and fattening. [1]

(e) Two signs of protein deficiency in pigs [2]

Any two of:

1. Slow growth rate / poor weight gain - protein is essential for building muscle tissue, so deficiency directly limits growth. [1]
2. Loss of body condition - the animal becomes thin or emaciated as the body breaks down its own muscle to supply amino acids. [1]
3. Poor hair or coat condition / rough, dull coat.
4. Reduced reproductive performance / smaller litter size.
5. Oedema (fluid swelling of tissues), particularly in severe cases.

(f) Importance of clean water for pigs in a fattening unit [1]

Water is essential for digestion, metabolic processes, and temperature regulation. [1] A lack of clean water reduces feed intake and slows growth, directly undermining the fattening objective.

Labelled answer diagram:

(a) Structures labelled X, Y, and Z [3]

1. X - Ovary: the paired organs that produce egg cells (ova) and the reproductive hormones oestrogen and progesterone. [1]
2. Y - Oviduct (fallopian tube): the narrow tube that carries the released egg from the ovary toward the uterus. Fertilisation normally takes place in the upper part of the oviduct. [1]
3. Z - Uterus (womb): the muscular organ where the fertilised egg implants and the embryo develops throughout pregnancy. [1]

(b) Function of structure Y (oviduct) [1]

The oviduct carries the egg from the ovary to the uterus by means of muscular contractions and the beating of cilia that line its inner surface. It is also the site where fertilisation occurs - sperm travelling up the reproductive tract meet and fuse with the egg in the oviduct. [1]

(c) What happens to the uterine lining if the egg is not fertilised [2]

1. If fertilisation does not occur, the corpus luteum on the ovary degenerates and progesterone levels fall. Without progesterone to maintain it, the thickened lining of the uterus breaks down. [1]
2. The lining is shed, and the animal returns to oestrus (heat), restarting the reproductive cycle. [1] In farm animals this is a cyclical process (the oestrous cycle), not menstruation as in humans - the lining is largely reabsorbed rather than discharged as blood.

(d) Two reasons for keeping accurate breeding cycle records [2]

Any two of:

1. To predict when the animal will be in heat (oestrus) so the farmer can plan mating or arrange artificial insemination at the optimal time for conception. [1]
2. To estimate the expected date of birth (parturition) so the farmer can prepare appropriate care, housing, and veterinary support for the pregnant animal. [1]
3. To identify animals that are not cycling regularly, which may indicate health problems requiring veterinary attention.
4. To plan the timing of breeding to ensure calving, lambing, or kidding occurs at the most favourable time of year.

Labelled answer diagram:

(a) Rotational grazing is a pasture management system where livestock are moved between different paddocks or sections of pasture in a planned sequence [1]. Each paddock is grazed for a set period and then rested to allow the grass to regrow before the animals return [1].

(b) The cattle should be moved next to Paddock X (or Paddock Y) [1], because the grass in those paddocks has regrown and is ready for grazing, providing sufficient forage for the cattle [1]. Paddock Z has been recently grazed and shows only short grass, so it needs more recovery time.

(c) Two benefits of rotational grazing compared to continuous grazing:

1. The pasture has time to recover and regrow between grazing periods [1]. This maintains healthy grass cover and increases total forage production over the year, whereas continuous grazing exhausts the pasture without rest [1].
2. Rotational grazing helps to break parasite life cycles [1]. Moving animals away from contaminated paddocks means larvae deposited in dung do not re-infect the same animals, reducing the worm burden and improving animal health [1].

Other acceptable benefits: reduces the risk of overgrazing (animals are moved before grass is grazed too short, preventing bare soil and erosion); ensures more even use of the whole pasture area.

(d) If all four paddocks become overgrazed, the farmer should:

1. Reduce the number of animals (lower the stocking rate) so the remaining pasture is not under excessive pressure [1].
2. Provide supplementary feed such as hay or silage to meet the animals' nutritional needs while the paddocks recover [1].

Other acceptable responses: rest all paddocks and move animals to an alternative holding area, or reseed and fertilise the paddocks to speed up grass recovery.

(a) Class of food nutrient most important for egg production [1]

Protein. [1] Egg white (albumen) is almost entirely protein, and the yolk also contains significant protein alongside fats. A laying hen requires around 16-18% crude protein in her diet to sustain peak egg production.

(b) Two other nutrients required by laying hens [2]

Any two of:

1. Calcium / minerals - essential for forming strong eggshells (each egg shell contains about 2 g of calcium). [1]
2. Vitamins - vitamin A for egg quality and resistance to disease; vitamin D for calcium absorption. [1]
3. Carbohydrates / energy - the hen needs energy for body maintenance and the metabolic cost of producing an egg daily.
4. Water - an egg is about 65% water; hens drink roughly twice the mass of feed they consume.
5. Fats / lipids - a concentrated energy source and needed for yolk formation.

(c) One reason laying hens require calcium [1]

Calcium is needed for the formation of eggshell. [1] The shell is composed mainly of calcium carbonate, and a hen deposits a new shell in the shell gland (uterus) every 20-21 hours. Without sufficient dietary calcium, shells become thin, soft, or absent.

(d) Three possible nutritional reasons for decreased egg production [3]

Any three of:

1. The feed may lack sufficient protein or essential amino acids (especially methionine and lysine), limiting the hen's ability to form egg white and yolk. [1]
2. The feed may be deficient in calcium or other minerals, leading to thin-shelled or shell-less eggs that the hen stops producing. [1]
3. The hens may not be receiving enough total feed (insufficient quantity), so overall nutrient intake falls below the threshold for production. [1]
4. The feed may lack vitamins (particularly A, D, or E), impairing reproductive function.
5. The water supply may be inadequate - dehydration quickly suppresses egg output.
6. The energy content of the feed may be too low for the hens to meet both maintenance and production needs.

(e) Advantage of allowing hens to range on pasture [2]

1. Pasture provides additional nutrients - green plants supply vitamins (A, K, riboflavin), minerals, and insects provide supplementary protein - that complement the formulated ration. [1]
2. This reduces feed costs because the hens obtain part of their nutritional requirement from foraging, so less purchased formulated feed is needed per bird. [1]

(f) What is meant by ad libitum feeding [1]

Ad libitum means the animals have unrestricted, continuous access to feed at all times. [1] Feed is kept constantly available in the trough or hopper so the birds can eat whenever and as much as they choose, rather than receiving set meals at fixed times.

(a) The plot that produced the highest yield was Plot 3, which received NPK compound fertiliser and yielded 210 kg. [1]

(b) The difference in yield between Plot 3 and Plot 1:

\[ 210 - 120 = 90 \text{ kg} \]

Working: Plot 3 yield = 210 kg, Plot 1 yield = 120 kg. [1]
Difference = 210 - 120 = 90 kg. [1]

This 90 kg increase represents a 75% improvement over the unfertilised control, demonstrating the substantial benefit of balanced NPK fertilisation.

(c) Plot 4 produced a lower yield than Plot 3 because it only received nitrogen and therefore lacked phosphorus and potassium. [1] Phosphorus is essential for root development and energy transfer, while potassium regulates water uptake and enzyme activity. Without all three major nutrients, the crop cannot achieve its full growth potential. This illustrates the principle that plant nutrition requires a balance of elements, not just one.

(d) What each letter in NPK represents:

1. N = Nitrogen [1] - promotes leafy vegetative growth and is a component of chlorophyll and proteins.
2. P = Phosphorus [1] - essential for root development, flowering, and energy transfer within the plant.
3. K = Potassium [1] - important for water regulation, disease resistance, and overall plant vigour.

(e) One advantage of using farmyard manure instead of chemical fertiliser: farmyard manure improves soil structure by adding organic matter, which increases the soil's ability to retain water and nutrients over the long term. [1] Other acceptable advantages: releases nutrients slowly; is cheaper if livestock are kept on the farm; less risk of polluting waterways.

(f) The farmer included a plot with no fertiliser because:

1. It acts as a control. [1]
2. It allows the farmer to compare the yields and measure the actual effect of each fertiliser treatment against a baseline. [1] Without a control, the farmer could not determine how much of the yield was due to the fertiliser and how much was due to the natural fertility of the soil.

Labelled answer diagram:

(a) Building A, with a sloping ramp leading into a narrow channel, is a dipping tank (cattle dip). [1] Livestock walk down the ramp into the channel containing an acaricide or insecticide solution, which treats them against external parasites such as ticks.

(b) Building B, a tall cylindrical structure, is a silo. [1] A silo is used to store animal feed such as silage (fermented green fodder) or grain in bulk.

(c) Two features of a well-designed livestock building:

1. Adequate ventilation (open sides, mesh walls or gaps between the roof and walls) to allow fresh air in and remove stale, humid air containing ammonia and pathogens. [1]
2. Sufficient floor space for the number of animals housed, preventing overcrowding which causes stress, injury and the rapid spread of disease. [1]

Other acceptable features: a sloping concrete floor for easy cleaning and drainage; a waterproof roof to protect animals from rain; feeding and watering troughs inside the building.

(d) Why the implement shed (Building D) should have good road access:

1. Machinery and equipment need to be moved frequently to different parts of the farm for field operations such as ploughing, planting and harvesting. [1]
2. Good road access allows tractors and implements to reach fields quickly, saving time and fuel costs. [1]

(e) Three reasons why the position of livestock buildings is important:

1. Wind direction: buildings should be placed downwind of the homestead so that odours and flies are carried away from the living area. [1]
2. Water supply: livestock buildings need a reliable water source nearby for drinking, cleaning and waste disposal. [1]
3. Drainage: the site must be well-drained to prevent waterlogging, which creates muddy, unhygienic conditions and encourages disease. [1]

Other acceptable reasons: accessibility for feeding, cleaning and veterinary care; distance from neighbours to reduce noise and odour disturbance.

(f) The feed store should be close to livestock housing to reduce the time and labour needed to transport feed to the animals. [1] Short distances also reduce feed wastage during transport and allow more frequent feeding.

(g) Two ways to maintain farm buildings:

1. Repairing damaged roofing sheets or thatch promptly to prevent water leaking in and causing further structural damage. [1]
2. Repainting or treating timber and metal surfaces with preservative or anti-rust coatings to prevent rot and corrosion. [1]

Other acceptable answers: replacing broken doors, windows or fittings; clearing drainage channels around buildings to prevent flooding; repointing or repairing cracked walls.

(a) The hand hoe method (cutlass and hoe) took the longest time at 80 hours per hectare [1].

(b) One hand tool other than a cutlass and hoe that could be used for land preparation: machete (or rake, spade, shovel, pickaxe, mattock) [1].

(c) Two advantages of using a tractor-drawn plough compared to a hand hoe:

1. A tractor covers a much larger area in far less time (4 hours vs 80 hours per hectare), making it dramatically faster [1].
2. A tractor produces a more uniform and deeper tillage, giving better soil preparation across the entire field [1].

Another acceptable advantage: requires less human physical effort and labour.

(d)(i) For a small-scale farmer with a 2-hectare plot and limited money, the animal-drawn plough would be most suitable [1]. It offers a good balance between cost and speed: it is much faster than the hand hoe (20 hours vs 80 hours per hectare) while costing significantly less than the tractor method ($200 vs $450 per hectare) [1].

(d)(ii) Two ways the farmer could reduce the cost of using animal-drawn equipment:

1. Share the animals and equipment with neighbouring farmers, splitting the costs [1].
2. Use own animals instead of hiring, eliminating rental fees [1].

Other acceptable methods: maintain the implements regularly to avoid costly repairs, and join a cooperative to share costs.

(e) The plot prepared with a tractor-drawn plough gave the highest maize yield because the tractor ploughs deeper and more thoroughly than the other methods [1]. This deeper tillage improves soil aeration, water infiltration, and root penetration, allowing the maize plants to access more nutrients and water from a greater volume of soil [1].