Technology Used in Food Production Ihe world population has been increasing rapidly in the past few decades. Hence, there is a need for increasing the quantity and quality of food. ihe need for improving the quality and quantity of food production is in line with our national food production policy. In Malaysia, there are a numher of agencies involved in research on increasing food production and improving the quality of food, 'lhis includes the Institute of Agricultural Research and Development of Malaysia (MARDI), Agriculture Oepartment and Fishery Methods which are used to improve the quantity and quality of food production include: (a)
direct seeding for rice
hydroponics and aeroponics
Direct seeding for rice In the traditional method of planting rice, seeds are sown in a nursery first. When they have grown into seedlings, they are transplanted to the paddy field. In direct seeding of rice, seeds are sown directly into the paddy field using special drills. ISTo transplant!ng is needed later on.
'Ihe advantages of direct seeding include: (i) less damage to the paddy plants as the method does not involve transplanting. (ii)
shorter maturation time, allowing planting of more than one crop in a year.
saves labour and the cost of production.
Hydroponics and aeroponics
Hydroponics and aeroponics are two methods of planting without using soil. I hey are usually used for growing vegetables. In hydroponics, the plants are placed in special containers, with their roots immersed in a culture solution to provide all the macro- and micronutrients needed by the plants. Figure 6.27 Hydroponics The plants are supported by sand or pebbles in the containers. The culture solution in the containers is replenished constantly as minerals are gradually depleted by the plants. It must also be aerated to supply oxygen for plant roots to respire. In aeroponics, the vegetables are supported by some framework with their roots suspended in mid-air in an enclosed chamber. The exposed roots are sprayed with complete culture solution and water alternately from time to time. The complete culture solution provides all the mineral nutrients needed by the plants. Figure 6.28 Aeroponics 6 The advantages of hydroponics and aeroponics are: (a) no soil or land is needed space-saving since the vegetables can be planted close together, temperature, light intensity and pests can be easily monitored and controlled, vegetables are provided with all the mineral nutrients they need. Hence, they are likely to produce better yield.
a Dry Questions 1 and 2 in Spotlight Access 6.14 Breeding 1 Selective breeding is a method of producing good crop plants or farm animals by crossing parent plants or animals of desirable characteristics. Desirable' characteristics include high yield, shorter maturation time, resistance to pests and diseases, and higher nutritional value. An example of selective breeding of crop plant is seen in the breeding of oil palm. In oil palm, desirable characteristics include a thick mesocarp and big kernel (the oil-rich parts of the fruit), and a thin shell (which makes cracking easier). The Dura oil palm fruit has a thin mesooarp (undesirable), a big kernel (desirable) and a thick shell (undesirable). On the other hand, the Pisifera oil palm fruit has a thick mesocarp (desirable), thin shell (desirable) but a small kernel (undesirable). The two varieties were successfiilly crossed to produce a new and ideal variety called the Tenera. The Tenera oil palm fruit has a thick mesocarp, a thin shell and a big kernel. In the selective breeding of cows, Friesian cows had been successfully crossed with Shahiwal bulls to produce the Mafriwal cow. Mafriwal cows yield more milk and meat. Tissue culture Tissue culture is used to produce clones of a good quality parent plant. In this technique, plant cells or tissues are stimulated to divide mitotically to form entire crop plants (clones) which are identical to the parent plant. Young tissues are preferred in this technique as the ability of young cells to divide is higher. The steps in tissue culture are as follows: (a) Young tissues are crushed to separate their cells.
(b) The cells are transferred to a culture medium. The culture medium provides all the necessary mineral nutrients for the cells to grow, and growth hormones to stimulate cell division (mitosis). Under these conditions, each cell divides mitotically to form an embryo which develops into a young plant. (c) The young plants are transferred to the soil to continue their growth into adult plants. 5 All the plants produced by tissue culture are identical to one another and to the parent plant because they are the result of mitosis. ( & "Dry Questions 3 and 4 in SpotUj^tt Access 6.14 } Genetic engineering 1 Genetic engineering is a technique whereby a gene which codes for a certain desirable characteristic is inserted into the DNA of an organism, so that it possesses that desirable characteristic. For example, a gene which codes for resistance to diseases can be inserted into the DNA of a crop plant so that it will become resistant to diseases. Other desired good characteristics include high yield and short maturation time. 2 Genetic engineering has successfully produced a variety of wheat which contains high-quality proteins, soy beans which contain all essential amino acids, and "golden" rice which is rich in beta-carotene. 3 Genetically engineered organisms (organisms which have received foreign genes) are known as transgenic organisms. Food produced by means of genetic engineering are called genetically-modified food (GMF). ^^ Soil management 1
Soil management is important to conserve its mineral content.
Soil erosion and leaching can cause minerals to be lost.
Ways to prevent soil erosion and leaching include:
Planting cover crops to prevent rain from directly hitting and eroding the
(b) Terracing or contour planting at hill slopes to reduce soil erosion by breaking the momentum of rainwater flowing downhill. Figure 6.30 Terracing (c) Practising crop rotation, whereby a different crop is planted on a piece of land each year so as not to deplete certain minerals. (d) Avoiding excessive use of agrochefnicals such as insecticides, herbicides and chemical fertilisers. 4 Besides preventing soil erosion and leaching, the ploughing of soil should be done regularly to allow air to enter to aerate it. ^ Biological control 1 Pest control is important in agriculture. Agricultural yield is often reduced by pests such as insects, caterpillars and rats which eat up the crops. 2 Pests can be controlled either chemically or biologically Chemical control of pests is done using pesticides. However, this may endanger consumers, as pesticide residues sometimes remain in crops and are eventually consumed. The spraying of pesticides also causes environmental pollution. 3 Biological control is the control of pests by using their natural enemies or predators. For example, rats in oil palm estates can be controlled by rearing owls or snakes to eat them. Biological control does not pollute the environment. It is also cost-effective. Spotlight Access 1
(a) Name two methods of planting crops
without using soil, (b) State two advantages of the methods mentioned. 2 Give an example to show how selective breeding has helped improve the quality and quantity of food.
3 Why are the crop plants produced by tissue culture identical to one another and to the parent plant? 4
State two methods of preventing soil erosion.