Strategies for the future (genetical modification, fertiliser, perennials, diversification and automation)
i) Genetic Modification (C4)
One strategy still available is genetic modification to create more productive crops like C4. Research on why plants need nitrogen have identified an important proteins (rubisco - an enzyme) in photosynthesis (the process of using energy from the sun to change carbon dioxide and water in the compounds necessary to make roots, stems, leaves and seeds). In nature, rubisco is not very effective and it needs a lot of nitrogen. C4 photosynthesis is an attempt to increase rubisco's effectiveness; it has done this in the lab by more than a factor of more than 60 times. Thus researchers are trying to convert plants like rice into C4 plants, ie
"...one that will grow faster, require less water and fertiliser, and produce more grain..."
Charles C Mann 2018
C4 is aiming to refashion photosynthesis (including photosynthesis to produce additional grains rather than other parts of the plant). At the same time, plants must be disease-resistant, easy to grow, nutritious and palatable
NB Rice is the world's most important foodstuff as it is a stable crop for more than half the global population. The demand for rice is expected to skyrocket with increasing population and affluence; the latter permits poor people to switch to rice from millet and sweet potato. However the land available to rice is shrinking as urban areas expand into the countryside, more demands are put on rivers for their water, farmers switch to more profitable crops and climate change reduces arable land.
It is expected
"...that C4 rice will use less fertiliser and water to produce every calorie - it will be better for the environment than conventional crops......only hyperintensive, industrial-scale agriculture using superproductive genetically modified crops can feed tomorrow's world..."
Charles C Mann 2018
ii) Fertiliser
A more controversial strategy is fertiliser. Yet
"...the amount of nitrogen in the soil controls the rate of plant growth..."
Charles C Mann 2018
Thus awillpplying nitrogen containing compounds, eg factory-made fertilisers, to the soil has a major impact. The Haber-Bosch process produces almost all the world's synthetic fertiliser. A little more than 1% of the world's industrial energy is devoted to it.
"...That 1%......roughly doubles the amount of food the world can grow..."
Ramez Naam as quoted by Charles C Mann 2018
"...nitrogen fertiliser from the Haber-Bosch process accounts for the prevailing diets of nearly 45% of the world's population..."
Vaclav Smil as quoted by Charles C Mann 2018
However, unfortunately most of the fertiliser applied is not absorbed by the plants - it is washed away. So the costs that need to be in the cost-benefit calculation include
"...fertiliser run-off, watershed degradation, soil erosion and compaction, and pesticides and antibiotic overuse.......destruction of rural communities......whether the food is tasty and nutritious..."
Charles C Mann 2018
iii) Perennials
Most common cereals (wheat, rice, maize, barley, oats, rye, etc) are annuals, ie planted annually. Perennials are more permanent:
"...Because perennial grasses build up root systems that reach deep into the ground, they hold onto soil better in the ground and are less dependent on surface water and nutrients - that is irrigation and artificial fertiliser - than annual grasses. Many of them are also more disease resistant. Not needing to build up roots every Spring, perennials emerge from the soil earlier and faster than annuals. And because they don't die in the winter, they keep photosynthesising in the autumn, when annuals stop. Effectively, they have a longer growing season. They produce food year after year with much less ploughing-caused erosion..."
Charles C Mann 2018
For example, wheatgrass is a perennial that is currently under evaluation for more widespread use.
iv) Diversifying (multiple alternatives)
Need to think about
"...replace......plots of wheat, rice, and maize with fields of cassava, potatoes and sweet potatoes and orchards of bananas, apples and chestnuts..."
Charles C Mann 2018
For example, cassava and potatoes out-produces wheat and other cereals; they produces more calories per hectare, eg potatoes yield 10 times the equivalent of wheat.
For tree crops
"...a mature Macintosh Apple tree grows 162 to 250 kilograms of apples the year. Orchard growers plant 500 to 625 trees per hectare. In good years this can work out to 88 to 160 tons of fruit per hectare. The equivalent figure for wheat, by contrast, is 3.75 tons......even papayas and bananas are more productive than wheat. So are some nuts, like chestnuts..."
Charles C Mann 2018
NB Most grain is destined for highly-processed substances, like animal feed, breakfast cereals, sweet syrups, and ethanol
For animals, it takes around 5 kg of grain to yield 0.5 of beef. On the other hand, cows with their 5 stomachs have evolved to eat grass, not grain. It is claimed that meat from healthy, grass fed animals is good for humans, ie
"...Grass fed and grass finished meat has been shown to be more healthful to humans than that from animals fed on soy and corn, containing high levels of omega-3 fatty acids, conjugated linoleic acid, beta carotene and other nutrients..."
Melissa Clarke 2019
v) Automation
Since the end of World War II, most countries (especially developed ones), have aimed to consolidate mechanised agriculture as a way of increasing output and reducing costs, especially labour, ie
"...in the United States, the proportion of workforce employed in agriculture went from 21.5% in 1930 to 1.9% in 2000; the number of farms fell by almost 2/3. The average size of surviving farms increased to compensate for the smaller ones..."
Charles C Mann 2018
Also government incentives, like tax concessions, training programs, loan plans, direct subsidies, etc have all encouraged consolidation, monocultural approach plus mechanisation of agriculture.