Lecture 1 - Water Footprinting, Agricultural Sustainability and Drought Tolerance

Flashcards reviewing key concepts from a lecture on agricultural sustainability, water footprints, and crop water management.

What percentage of global water withdrawals does agriculture account for?

Approximately 70%

In the USA, what percentage of greenhouse gas emissions are attributed to agriculture?

Around 10%

What is the estimated human population of Africa by 2050?

2,000,000,000 people

What percentage of crops grown on Earth is rain-fed agriculture responsible for?

About 80%

What percentage of the world's food does rain-fed agriculture contribute?

Approximately 60%

What percentage of crop lands are irrigated?

About 20%

What percentage of the world's food is supplied by irrigated agriculture?

About 40%

What are the three key factors to consider when evaluating the sustainability of agriculture?

Environmental health, economic profitability, and social/economic equity

What is the difference between applied resource use efficiency and intrinsic resource use efficiency?

Applied resource use efficiency is crop yield divided by resource applied. Intrinsic resource use efficiency is crop yield divided by the amount of resource the plant takes up.

What is peak nonrenewable water?

The point when the rate of abstraction of groundwater exceeds the rate of recharge back to the aquifer.

What leads to peak ecological water?

When the costs of environmental damage exceed the value of the human use of that water.

What is the main issue in the North China Plain concerning agriculture?

Aquifer height is diminishing because of double cropping and the need to extract water for the second crop.

What is the water footprint mainly determined by?

Our consumption of agricultural goods.

What is the relationship between humidity and transpiration?

In environments with high humidity, there is limited tendency for water to move from inside the plant (transpiration).

What three factors primarily impact the water footprint of crops?

Cropping location, crop management, and atmospheric evaporative demand.

What are the three different types of water footprint?

Green, blue, and gray water footprints.

What is the green water footprint?

The water from rainfall that is stored in the soil and then evaporated, transpired, or incorporated by the plant.

What is the blue water footprint?

The use of surface water or groundwater resources for irrigation.

What is the gray water footprint?

The amount of freshwater required to assimilate pollutants from agricultural systems.

What determines the tendency for water to move from inside the leaf to the atmosphere?

Atmospheric evaporative demand or vapor pressure deficit (VPD).

Which dominates The UK's agricultural water footprint: domestic production or imports?

The UK heavily relies on imports to meet the commodities that contribute to their water footprint.

Which country provides most water footprint to The UK due to import of Beef and Soybean?

Brazil

How does local rainfall influence wheat's water footprint in the UK?

The UK wheat water footprint is about half the global average due to the humid atmosphere.

Which country is exporting tomatoes to The UK the most, besides Southern Spain and France?

Morocco, which is even more water-stressed than Southern Spain and France.

Where do the majority of Spanish tomatoes come from?

Protected cultivation, large poly tunnels designed to shield crops from the dry atmosphere and lower evaporation demand.

How much water is required to produce one tomato?

Around 50 liters of water, globally.

What is the potential benefit of using specific rootstocks in Spanish tomato production?

Significant water savings, potentially enough to guarantee domestic supply for around 100,000 people.

What relationship exists between crop yield and the rate of evapotranspiration?

There is a linear relationship between crop yield and crop evapotranspiration.

How does water saving in the pre grain filling period relate to final crop yield?

In some environments we might want to save water during this pre grain filling period so that we've actually got water available at the time that the crop is filling the grain.

What structures in the plant stem conduct water from the roots to the shoots?

Xylem vessels.

What are some traits that we could look at to either save water, escape drought, or indeed spend more water to try and boost our crop yields in water limited environments?

Select more efficient varieties in controlling their transpiration through stomatal regulation, crops that develop more rapidly to escape, or plant that is able to access water deep in the soil.

What did the speaker conclude about the commercial value from hybrid seed producers?

Difficult to understand from a scientific perspective. The important to try and evaluate these claims that biotech or seed production companies make and put them within the proper scientific context.

What transgenic Maize species are released commercially?

A genetically modified maize variety released to enhance drought tolerance

How has the transgenic maize variety released enhanced drought tolerance, in a dry environment?

It prioritizes the use of water for growing the ears of the grain.

What are the three categories of action, plant breeders or biotechnologists can target specific traits of the crop?

Improved root growth to take up water, reduced xylem vessel diameter to restrict the flow of water through the plant and changing the stomatal sensitivity to the environment so that the plant saves water

What is harvest index?

The harvest index meaning how much of the biomass the crop ends up as yield and how much is simply vegetative growth

What is the speaker's view on inheritance tax, in agricultural science?

Inheritance tax is unfair tax that is compromising their ability to turn a profit

Why is agriculture fundamentally a business?

The decisions that farmers make are usually with economic sustainability in mind

Why is illegal immigration in the European Union of concern?

Government immigration policy concerns humans, doesn't really too too concerned about biosecurity sometimes and this herbicide resistant weed was found, diagnosed, and I guess there's some quarantine measures in place to try and stop this herbicide resistant weed spreading in its environment

What are the possible effect of fertilizer on crop productivity?

Fertilizer use enhances crop productivity, enhance both for human safety, but also the safety of our environment