How to grow more food from less land

Rising food prices, gaps on shelves and requests from supermarket chains to be kind and try something else if a favourite brand or item isn't available ... supply chain disruptions are real and food shortages are global.

Already there are warnings about the potential for food riots to occur, just as they did during the Global Financial Crisis. War and Covid-19 have exacerbated the issues caused by drought, fire and flood.

In addition, there is the overarching pressure to meet the nutritional needs of an ever-increasing world population.

Scientists are thinking globally as they grapple with the complexities of available land, climatic conditions, biodiversity and the number of mouths.

How can we feed more people to a better state of nutrition using no more land, while reducing the risks to production?

German researchers have modelled the options.

In a paper released this year, they suggested that improved efficiencies in crop production could increase production by almost 3 per cent while reducing the area required for growing crops by between 37 per cent and 48 per cent.

This would allow land to stay ‘natural' and host biodiversity. In addition, the researchers estimated that crop prices would decrease.

Achieving the scenario requires overcoming the yield gap, which is the difference between average global yields and possible yields. Agricultural intensification - fertiliser, irrigation and crop protection chemicals - is the key.

Globally yields of wheat hover around 3.5 tonnes/hectare, but 17.389 tonnes/ha is possible.

Eric Watson is the holder of the global record in The Guinness Book of Records. Watson farms in Wakanui, Canterbury, New Zealand. His yield in 2020 was five times that of the world average, growing in the relatively ideal conditions of NZ, with all the modern technologies available.

Another publication this year suggested that relocating crop land to areas where water is available would cut the carbon impact of global croplands by 71 per cent, by allowing the drier land to revert to forestry.

Like the German study, the inter-country team led by the University of Cambridge UK concluded that high-input, mechanised farming was required to be successful.

By focusing on carbohydrates (crops), however, both the studies missed the limiting factors for human nutrition in the future - calcium and essential amino acids.

The Sustainable Nutrition Initiative hosted by the Riddet Institute at Massey University is working on it. Another research paper this year, this time with authors from Massey University and Fonterra, analysed the contribution various foods make to nutrition. The goal was to identify how the world can best position for meeting future nutritional needs. Like the previous two studies, the research involved modelling scenarios.

In this case, the DELTA Model, which considers 29 nutrients and calculates the available nutrition from global food production scenarios, was used to examine the role of milk.

The authors found that milk contributes to the global availability of 28 of the 29 nutrients in the model.

"Milk is the main contributing food item for calcium (49 per cent of global nutrient availability), Vitamin B2 (24 per cent), lysine (18 per cent), and dietary fat (15 per cent)" stated the authors.

"More than 10 per cent of global nutrient availability for a further five indispensable amino acids, protein, vitamins A, B5, and B12, phosphorus, and potassium was also contributed."

And all the nutrients were provided for only 7 per cent of food energy requirements.

Further research indicated that among the 98 food items considered by the model, milk ranked in the top five contributors to 23 of the 29 nutrients modelled.

Although the cynic might expect authors associated with Fonterra to conclude the value of the milk, the research backs up a 2016 research paper led by New Zealand nutrition scientist Dr Graeme Coles.

The authors concluded that when assessed as all-year-round production systems, mixed dairy/cropping provided the greatest quantity of high-quality protein per unit price to the consumer, had the highest food energy production and could support the dietary requirements of the highest number of people.

Nutritional security requires protein as well as calories, and Coles has calculated that a cheese sandwich meets dietary requirements for the least cost.

For the Canterbury Plains, the optimum allocation of prime arable land involved animals - dairy cows producing the milk products that contain so many nutrients essential for human nutrition. It also included beef and sheep finishing on pasture grown between crops - as is relatively common over winter.

Life cycle analysis by AgResearch scientists has shown that greenhouse gases and nitrogen loss per kg of product (meat and milk) are lower in New Zealand than in other countries. But nobody is resting on laurels. Farmers and scientists are continuing to try to reduce the food footprint still further, and to assist other countries to improve their production systems.

The yield gap exists in all sectors, not just cropping, and the gap applies to environmental impact as well.

Science is looking at the big picture for food production, and New Zealand researchers and farmers are showing what can be done while trying to do even better.

Although there will always be seasonal fluctuations in the price of vegetables and fruit, and supermarket loss leaders and general ‘specials', food prices aren't likely to reduce in the future.

Being kind is important, but so is being realistic about the global problems.