[14.8] A SUSTAINABLE FUTURE

HYDER CADERSA and AMANDEEP SINGH HEER

What is a sustainable future?A future that

involves keeping pace and improving environmental conditions over a period of time

To have this kind of future, people need to preserve the different species of plants

INTRODUCTIONOur future depends on increasing our understanding and utilization of plants. Demand for human food will drastically increase as population passes 8 billion

NEW KINDS OF PLANTS ( PART 1)• Finding and breeding new plants to increase the limited number of plants currently under cultivation• Some plants do not require inputs of nitrogen and are less expensive to growE.g.) Winged bean of New Guinea

NEW KINDS OF PLANTS ( PART 2)Amaranths Plant produces large quantities of seeds rich in protein a) contains amino acid lysine which is good for our diets b ) mixing small amounts of amaranth flour with wheat flour greatly enhance nutritional value•wax gourd a) stored without refrigeration for up to a year

NEW KINDS OF PLANTS ( PART 3)Spirulina - marine cyanobacteriuma) can be grown in saltwaterb) Is photosynthetic and nitrogen fixingc) It is more productive that wheat fields and has higher protein content than soybeansd) promising source of protein

LAND BASE ( Part 1)• pressure to plant crops is clearing out rainforests• poor cultivation and changing climate lead toa) soil erosionb) reduction in genetic biodiversity and land base fit for agriculturec) desertification

• Global Warming and Climate change will impact food growing regions and forests• land suited for agriculture already under cultivation• freshwater resources are scarce, in areas where irrigation has been used up, groundwater is running out and the soil is becoming salty• 200 000 hectares of irrigated cropland become useless for food production each year due to salinization

Land Base – part 2• Salinization- the process in which salts in groundwater is brought to the surface by irrigation and left to build up there after the water is lost in plants by evaporation and transpiration• halophytes- plants that can grow in deserts, salt marshes and coastal regionsE.g.)1. Atriplux Patula2. Hippophae rhamnoides, a

shrub3. The Russian olive tree

Genetic Diversity• The most important step is to preserve the plants in threatened ecosystems

• Their closest wild relatives must also be collected and preserved because future range of plants depends on current ones• New crops, medicines and plants will be derived from these• As oil reserves become scarce, demand will rise for alternative and renewable sources of industry materials and energy•E.g.)1. Palm oil - 28 000 species have been

studied. It is used in hundreds of different products from lipsticks to jet engines

2. Guayule – a desert shrub, now under cultivation in over 30 countries, excellent source of high quality natural rubber

Questions 1. Why are new varieties of

nitrogen-fixing bacteria so eagerly sought?

2. How does the chemical composition of amaranth seeds make them particularly valuable?

3. List some factors which limit the availability of more land for the cultivation of crops.

4. a) What are halophytes? b) What would be the

advantage of finding a highly nutritious halophyte?

5. How can the routine irrigation of soil with normal well water lead to salinization?

Answers1. New varieties of nitrogen-fixing plants do not require inputs of nitrogen to

grow and are therefore less expensive to grow and better for the environment.

2. Amaranth seeds produce large quantities of proteins. One of these amino acids produced, lysine, is essential for out diet but is rare in plant proteins.

3. Factors which limit availability of more land for cultivation of crops are most land suited for agriculture is already under cultivation, salinization from irrigation has left the land useless and poor cultivation practices and changing climate patterns have led to soil erosion and desertification.

4. a) Halophytes are plants that can tolerate living in salty habitats due to their ability to absorb water from concentrated solutions.

b) A highly nutritious halophyte could be grown on coastlines and deserts and would use salt water instead of scarce fresh water for irrigation.

5. Dissolved salts from groundwater are brought to the surface during irrigation. The water is lost through transpiration and evaporation, leaving the salts to accumulate behind on the soil. The salty soil soon becomes useless for food production.