Lesson video

Hello, geographers.

My name is Mrs. Griffiths.

Welcome to the lesson.

Today's lesson is all about different strategies that can be used to increase food production.

And we're gonna look at a real world example in an area of Kenya where serious money has been invested to increase rice production.

Should we get started? And our outcome for today is as follows.

I can describe different strategies used to increase food supply and outline the advantages and disadvantages of Kenya's Mwea irrigation scheme.

So that's what I want you to be able to say by the end of today's lesson.

And we have some key words today.

The first is hydroponics.

Hydroponics is the growing of plants using mineral nutrient solutions in water and without soil.

Then we have aeroponics, growing plants in a mist environment without the use of soil.

Biotechnology, which is the use of technology to modify organisms or processes, for example, genetically engineered crops.

I have two more keywords for you here.

Key terms, the New Green Revolution.

This is an approach to boosting food production that seeks to benefit poor farmers bypassed by the original Green Revolution and conserve the environment.

Appropriate technology.

This is technology suited to the needs, skills, knowledge, and wealth of local people in the environment in which they live.

So look out for those keywords and key terms cropping up across the lesson.

Now, how does our lesson break down? So we have two parts.

Firstly, we're gonna answer this question, how can we increase the global food supply? I'm going to look at a range of strategies.

And then secondly, we'll think about will Kenya's Mwea irrigation scheme help? How will it help? But let's start with this first question.

So with a growing global population and wealthier populations consuming more, how can we increase the global food supply? Well, we're gonna look at a range of different strategies.

So let me just outline which ones we're gonna look at.

So we have irrigation, hydroponics, aeroponics, biotechnology, the New Green Revolution, and appropriate technology.

So all of our keywords coming up there.

Now, if we start with irrigation, irrigation is applying water to land in order to supply crops or other plants.

And look at that image.

Perhaps it's familiar to you having been on holiday.

It certainly is to me.

Sites like this are common in mainland Europe where the climate means crops need additional water to support the harvest during hotter, drier months.

For example, you might have seen this in Southern France.

Now, irrigation systems, sorry, don't always look like that.

They vary in terms of their scale.

So we might have very large scale systems involving dams to create reservoirs and canal systems to distribute that water.

From that we might go to a field scale sprinkler system as pictured here.

However, we could also have drip irrigation from leaky hoses, feeding individual plants, and then right to sort of micro scale where we just got the laborious use of buckets and watering cans.

So barely any technology involved.

Irrigation can boost crop yields or avoid crop loss due to drought and resulting wilt.

And we can see in this picture of drip irrigation, we can really picture how in a hot, dry environment, this is lifesaving crops.

There are some problems with irrigation, however, and these include salinization.

So this is the buildup of a salt crust on the soil because of the way that water is drawn back to the surface by the process of evapotranspiration.

So that salt crust can actually impede the growth of crops over time.

Water logging, sorry.

So the opposite situation where you've got poor drainage.

And if water is on a continuous basis being added to the soil, you've got water logging and that no air can get to the roots of plants and the plants will die.

Large scale irrigation schemes may disrupt the movement of water for many downstream.

So think about if there's an irrigation scheme that dams a river, then the people that were using that river water downstream may have their livelihoods changed.

Alternatively, where we just think about the site of that reservoir, actual construction of the reservoir and the completion of the dam will involve flooding an area, which will force people off the land.

So positives and negatives to irrigation for you there.

True or false, irrigation is a key strategy for increasing global food supply and has no disadvantages.

I'd like you to pause the video, discuss this with a partner, and then restart it when you have an answer and you can explain your answer.

And if you said false, what was your explanation? We had salinization and waterlogging of crops are both problems caused by the mismanagement of irrigation.

Knock on effects of the diversion of water and losses by evapotranspiration may be felt downstream.

So thinking about when you've got water trapped in a large reservoir, actually there's losses of water by evapotranspiration from that lake and that might create supply issues downstream as well.

Well done if you had something like that.

So our second strategy here is hydroponics.

Now hydroponics is the growing of plants using a water-based mineral nutrient solution and without soil.

And if we have a look at the image we have there, we are clearly indoors in what looks like a large greenhouse.

And I can see lettuces growing in trays rather than the soil.

And we've got a cable there showing either supply of water or possibly that's power.

But we can see that water must be held in those trays to sustain the lettuces.

So plants grow in the liquid that provides with nutrients or alternatively, might be planted in a gravel or other substance which mechanically supports them, I suppose, which is doing the job that soil does into which nutrient solution is added with precision and automation.

So this is a highly technological way of growing food.

In this scientifically controlled environment, water and nutrient use is much less, production is much greater.

So we've got boosted harvests here, but the costs are high.

So only, it's only useful for growing high value food.

So here we've got a salad crop.

Now, aeroponics is a form of hydroponics and here we can see the plant's roots and the these roots are what a mist is being delivered to to supply the nutrients.

So nutrients are delivered directly to plant roots and plants grow more quickly supplied by this mist solution.

All forms of hydroponics involve growing food indoors you'll have noticed in a greenhouse to make best use of the investment made in this technology so that they can control all the other factors involved in growth.

So all other conditions such as temperature, ventilation, light, and pests are controlled that might affect the high value fruit, all vegetables that are grown.

And remember I said that these techniques are really only any good for high value goods that you can recoup the investment on.

Now, a real world example is Thanet Earth, which is an agribusiness in Kent in the southeast of England that uses hydroponics.

Thanet Earth employs this technology in giant greenhouses to supply the UK with salad vegetables.

And we've got an aerial view there showing some of these huge greenhouses.

Note the scale at the bottom of that aerial image of 400 metres.

And we can see that at least two of those greenhouses are 400 metres across.

So in Kent, temperatures are mild for most of the year with a higher number of sunshine hours compared to other UK regions.

So clearly, this business has thought about where to locate.

The greenhouses are artificially heated and lit during the colder months using combined heat and power generators on site.

So it's still growing salad veg in the UK.

So let's be realistic about that.

Thanet Earth is the largest greenhouse complex in the UK and it covers 0.

9 square kilometres in glass.

So it's using technology to control the environment and producing cucumbers, peppers, and tomatoes.

What sort of technology they're using? Well, they're using hydroponics, as I mentioned, where the plants grow in that substrates.

They're growing in some form of mineral wool to which the nutrient solution is added.

The business also employs introduced species of insects which have been bred to prey on pests.

So it involves biotechnology here.

And more recently, robots are being used to pollinate tomatoes, which apparently are much more effective than bees.

But that's a recent update on this agribusiness.

The growing season has been much extended compared to the average for outdoor crops in the southeast of England.

For example, tomatoes are harvested across all 12 months of the year and cucumbers and peppers are harvested February to October.

So really different in terms of the way that salad vegetables can be produced in the UK almost all year round.

There are some downsides to this production.

I've talked about the high cost.

We've also got light pollution from the greenhouses, which is a local issue during the winter months.

And the business has had to respond by fitting blinds, but there's still some light pollution.

But a vast agribusiness that has succeeded in increasing food production.

Which of these images shows hydroponics and how do you know? Pause the video now and restart it when you think you've got the answer.

And if you said A, you'd be absolutely right.

Our explanation was, well, hydroponics is the growing of plants using mineral nutrient solution without soil.

Image A shows plants growing indoors in elevated trays.

Okay, so the others are clearly outdoors.

So high-yielding varieties of crops were developed in the 1960s by a process called hybridization.

So we're talking about the original Green Revolution here.

And here I've got a line graph showing change in serial production in India over time from 1960 onwards.

And the red line is serial production, the bluey green line is serial yield, and we've also got population of India showing how that's changed over time, as well as land used for cereal, which doesn't look to have radically changed across that period.

However, cereal production and cereal yield has hugely.

Food supply in cereal crops like rice and wheat has increased dramatically since the 1960s.

While the Green Revolution benefited large scale farmers, however, few small holders in low income countries could afford high-yielding variety seeds along with the necessary fertilisers and pesticides.

And it's all about that.

It's about the cost of these inputs meant that big businesses benefited, but smaller farmers couldn't employ this strategy linked to what we call the Green Revolution.

Now, biotechnology has moved on since the 1960s when hybridization was being used, and we've now used that term to describe genetic engineering.

So we're talking about the manipulation of living organisms, taking the gene from one organism, and adding it to the genetic makeup of another in a laboratory.

So scientists, by doing this, can create crops with desirable characteristics.

For example, drought resistance, crucial for climate change adaptation.

Disease or pest resistance, reducing the need for spraying crops with pesticide.

And thirdly, we've got additional vitamins.

So adding those vitamins or higher protein content.

So the nutritional value of a product is being boosted.

And I can think of a real world example where the gene of, I think it was the snapdragon plant was added to the genetic makeup of a tomato to create a kind of a bluey-colored tomato that was high in antioxidants.

So that was one commercial product that was a GM food.

The use of GM crops is currently limited in the UK and the EU.

Well, why is that? Food containing GM ingredients must be clearly labelled, given concerns about unknown impacts on health and the environment.

After all, this is quite a new technology.

However, in other countries, including the USA, there's been less debate about the use of biotechnology in food production.

And Brazil and Argentina are the next largest producers of GM food after the USA.

In Asia, China is a major producer of GM food, including some fruits and vegetables.

This technology is really being used to boost food supply in some regions of the world.

Now, appropriate technology is a bit different.

It's technology suited to the needs, skills, knowledge and wealth of local people in the environment in which they live, and you might have come across this in other units of your studies.

And in the image, we've got an example here of appropriate technology.

We're looking at a solar-powered water pump that is providing a bucket of water that we can use to irrigate crops.

The term New Green Revolution refers to an approach boosting food production to benefit poor farmers bypassed by the original Green Revolution, that hybridization revolution I talked about in the 1960s, and conserve the environment.

Appropriate technology is part of this New Green Revolution and it's something that offers sustainable solutions to increase food supply as part of the new approach.

So the concern with the original Green Revolution linked to hybridization and fertilisers and pesticides you'll remember was about high cost and large numbers of inputs and a concern about the impact on the environment and also people that couldn't afford to take part in that revolution.

So techniques such as permaculture mimic natural ecosystems. So this is the idea of intercropping.

And we can see in the image, we can see lots of crops that appear to be different.

We can see different shapes, leaves, and the colour of the leaves, but they're planted very close to each other.

And this intercropping means different plants protect the soil year round from wind and water erosion and are also parts of this New Green Revolution.

So it's about conserving the soil whilst farming.

Check for you here.

Which of the following are linked to the New Green Revolution? So we have A, B, C, and D.

I'd like you to read those through.

Discuss it with a partner and then restart it when you have the answer.

Okay, how did you get on? If you said A, B, and C are all linked to the New Green Revolution, you'd be absolutely right.

High-yielding varieties of crops plus artificial fertilisers are not part of this New Green Revolution.

That was the original Green Revolution.

Okay.

Task then for you.

You might need to grab a pen or pencil for this one because we're going to complete the fact file on strategies to increase food supply.

So we've got three of the strategies we've looked at there; irrigation, hydroponics, and biotechnology.

And I'd like you to write me a short note about how it works and then think about what the advantages and the disadvantages are.

But as I say, putting pen to paper here.

Secondly, I'd like you to explain what is meant by the term New Green Revolution.

New Green Revolution.

So have a think about that.

So pause the video now and then restart it when you think you're ready to check your answers.

Okay, how did we get on? So we completed the table here and we can see that for irrigation, it's about the addition of water to land.

It has some advantages like higher yield, but the disadvantages are salinization or alternatively, waterlogging.

Hydroponics is about the growing of plants using mineral nutrient solutions in water, but without soil.

And the advantages are it's water efficient, it's also efficient in terms of nutrients, and produces a high yield and faster growth.

So loads of advantages, but also we know it has disadvantages in terms of cost.

Bio-technology is the use of technology to modify organic products or processes, for example, creating genetically modified crops.

But the downsides are that actually, it's unpopular in some parts of the world because the impacts are not known.

So, so far, it has had a sort of uneven impact on food production.

Okay, and question two, you were asked to explain what is meant by the term New Green Revolution.

So here's an example for you of what you could have written.

In contrast to the Green Revolution that took place in the 1960s or from the 1960s and in lower income countries in the 1970s and the 1980s, the New Green Revolution is an approach to boosting food production that seeks to benefit poor farmers bypassed by that original revolution and conserve the environment.

For example, there is a focus on small-scale farmers in the world's poorest countries.

While the introduction of high-yielding varieties of crops and the initial Green Revolution boosted harvests, but depended on the use of expensive fertilisers and pesticides, the New Green Revolution employs techniques that mimic natural processes such as permaculture.

Appropriate technology is also key, involving low tech, sustainable solutions such as solar-powered irrigation.

Now, if your answer gets some of that across about the key elements of the Green Revolution, then it's a very good answer.

Well done.

So in the second part of the lesson today, we're gonna think about, will Kenya's Mwea irrigation scheme help.

So we're gonna be focusing on a particular scheme in Kenya.

So here's a map of the scheme, quite detailed map, and we can see the little inset map locates the Mwea irrigation scheme within Kenya itself in East Africa.

You can see it's just north of Nairobi.

So Kirinyaga County is a hundred kilometres northeast of the capital Nairobi.

And within it, we have this Mwea area with the town of Wang'uru at its centre.

So Wang'uru is an urban centre with a population of seven and a half thousand people, and it's located at the heart of this scheme.

We look at the map, we can see that the yellow is the existing irrigation area and the green is something called irrigation extension, which I'm gonna flesh out in a moment.

But first, it's worth showing you that this is a scheme that hasn't just come about overnight.

It's come about over decades.

So in 1991, an inter-basin, so an inter-basin link was constructed to transfer water from the Nyamindi River to the Thiba River to increase irrigation.

And if I add this arrow, you can see how those two river, you see how those two rivers are linked.

And if you look for that red link canal, you can see how water has been transferred.

However, there's been an update on this scheme because in 2022, Kenya's first irrigation dam was built at Rukenya.

So it was the Thiba dam at a place called Rukenya, north of the Mwea irrigation scheme as was.

So the Thiba dam has stabilised the water supply for farmers to the south and increased meant, the increase is possible in terms of the area of rice farming from a hundred square kilometres to 140 square kilometres.

So that's where that green irrigation extension comes in.

And we can see the link canal has been extended to link that area up.

The dam and associated infrastructure will support double cropping.

So two crops within a year, increased food security for this area of Kenya and nationally, and create a hundred thousand farm jobs, increasing incomes and therefore quality of life.

So it's a really large impact scheme.

Here's a map of Kenya showing the location of Kirinyaga County.

And if we switch to looking at satellite imagery and aerial imagery, just to sort of locate this and get a sense of the impact of the scheme, I would say it's fairly easy to locate this area using satellite imagery because if you look at Kiranyaga County, it's quite a distinctive shape.

It's almost like an upside down ice cream cone to my mind.

So if we start with Mount Kenya, which is very easy to spot, if we look south of that, we can see, so there's Mount Kenya, and then south of that, we can see there's a little dark area on our image, which is in fact where the Thiba dam has created a reservoir.

So that's located in this too.

And then south of that, we can see Wang'uru, which is a settlement located at the heart of the irrigation scheme.

Can you see that green area? Let's zoom in a bit, make it a bit clearer.

Okay, so let's start with looking at the dam just to show you because it's recently been completed.

Using historic imagery, we can see how much the landscape of Rukenya has been changed as a result of the completion of the Thiba dam.

So here in 2021, I'm using historic imagery from Google Earth here.

We can see that actually, there's a lot of construction underway, but nothing's been completed and we don't have a large reservoir.

But by 2024, the reservoir is in place.

We can almost see clouds and mist forming over the water there.

And I can add the dam just to show you there's a huge dam involved which is 40 metres high and it's a kilometre in length, so not a small scheme this one.

Using current satellite imagery, we can zoom in to see the irrigated rice paddy fields far to the south of the dam.

So here we can see a bright green landscape in this satellite and an aerial imagery shot.

The area around Wang'uru appears to be much greener than the surrounding landscape.

It's almost in a sort of incomplete donut-shaped shape around Wang'uru.

And then here we're zooming into an area west of Wang'uru where we can see there's a label there, Karima village.

Let's just keep our eye out for that.

To the north and west of Wang'uru, there is a patchwork of irrigated fields which is visible at this scale, but we can zoom in a little bit further to have a look at this intensive irrigation and the impact on agriculture.

So remember, I talked about the Karima village label and this is zooming right in to look at that village, which appears to be surrounded by these green strips of land, which are being irrigated by canals.

Now, it's fair to say on Google Earth you can take a different view, you can take a 3D view.

And here I've used this GIS tool to get a sense of the 3D nature of the landscape.

So I hit, we can see Mount Kenya in the distance far, far away.

Karima Village in the foreground surrounded by that patchwork of fields.

And I've just labelled the canal to show you how water is being distributed and channelled long distances to supply the rice crop here.

Just flagging there the button on Google Earth so we know how you can switch between the 3D and the 2D view.

True or false for you then.

The Mwea irrigation scheme has boosted Kenya's food supply.

Is that true or false? Remember, I need you to explain why.

And if you said true, how has it boosted it? What's it made possible? Well, the new Thiba dam has, and the water supply for irrigation of crops has meant that this cropping process is more reliable and it means that two crops of rice within a single year is now possible.

It's also extended the actual land area in which rice is being produced.

Are there any downsides to the scheme apart from the fact I guess it costs a lot to build? Izzy asked.

Well, you're absolutely right.

It costs a lot to build.

It costs many millions of dollars to build this scheme and also involved international loans.

But thinking about other downsides, high-yielding varieties of rice may be vulnerable to disease.

And similarly, monoculture environments are vulnerable to disease where you're just growing one single crop.

And that's a bit of a concern when this large area of the county that's covered in one single cash crop.

So a few disadvantages.

The irrigation system needs constant maintenance to work effectively.

So that's, those are the canals.

This is expensive and it's not always been carried out in this context.

As a result of this and sort of teaming problems with the design of the network, uneven water distribution has resulted in some areas receiving too much water and others too little.

And we've talked about those issues, haven't we? About potentially salt crust developing or the other way around.

We've got to water logging issues.

As I say, over irrigation can lead to salinization where salt's drawn towards the surface and deposited to form an infertile crust on the soil.

So there is that concern about this process.

There are further disadvantages.

So intensive rice production can be vulnerable to rice disease such as rice blast and pests such as the invasive freshwater apple snail, which cuts rice stems at the base, killing the plants.

Poor infrastructure has led to difficulties delivering grain from farms to mills.

So that's perhaps less of a disadvantage, but a limitation of the impact of this scheme in this particular context.

Which of the two, sorry, which two of the following are disadvantages of Kenya's Mwea irrigation scheme? So pause the video now, have a read through, and then restart it when you think you've got the answer.

And if you said, well, A and B are both downsides, so uneven water distributions resulted in some areas receiving too much water and others too little, clearly that's a downside.

High-yielding varieties such as intensive rice production are vulnerable to pest and disease, you'd be absolutely right.

So task for you here.

Grab a pen and potentially grab a bit of technology so you can go online for this because the first task involves you using GIS to locate the Mwea irrigation scheme.

And I'd like you to sort of explore it, looking at it from the air 2D and and 3D view.

So I'd like you to locate these three features and I'd like you to describe the location of the Mwea irrigation scheme and describe the landscape specifically to the west of Wang'uru.

So you're gonna need to focus in for that task.

Secondly, I'd like you to outline the advantages and disadvantages of Kenya's Mwea irrigation scheme.

So thinking about what we talked through today.

Pause the video now and restart it when you want to check your answers.

Okay, and how did you get on? I hope you enjoyed using that GIS package, whether it was Google or another package to explore this area.

It's fascinating aerial imagery.

Here I've located the two, the, sorry, the three features I wanted you to identify, but let's have a look at 1A.

You were asked to describe the location of the Mwea irrigation scheme.

We have the answer as follows.

The scheme is located south of Mount Kenya in Kirinyaga County in Kenya, East Africa.

Irrigated rice paddies surround the settlement of Wang'uru.

Secondly, we had to describe the landscape to the west of Wang'uru using this aerial imagery.

And our answer is the relatively flat landscape west of Wang'uru is covered in small strip-like fields that appear to be intensively farmed, divided by network of narrow local roads.

Large canals deliver water to the fields.

So what I like about that answer is we've got a sense of the topography of the relief.

So it's talking about it being a relatively flat landscape, but we also get a sense of not only the physical geography, but the the human geography, what people have built in that environment in terms of the roads and the canals and the fields.

So if you have an answer like that, well done.

Secondly, I ask you to think about the advantages and disadvantages of the scheme.

There are lots of different ones, aren't there? We have as follows.

So advantages.

It's double the region's crop production because the water supply enables double cropping and extends the land area farmed.

It's expected to generate up to a hundred thousand farm jobs.

And clearly, with that secure income, we've got improved standards of living, which links to food security.

And we've also got the idea that not only does it boost the country's food security, but it potentially boosts Kenya's international trade and perhaps the food security of other countries as well.

The disadvantages of this scheme are that the canals need constant maintenance, which is very expensive and not always carried out.

As a result, we've got uneven water distribution and that's meant that some areas have received too much water and others too little.

Intensive rice production can be vulnerable to diseases and pests that destroy the crop.

So we've got a potential weakness there in terms of the design of the scheme in this sort of monoculture environment.

And over irrigation can result in salinization, creating an infertile crust or potentially that idea of waterlogging if the drains don't function correctly.

So in summary, what have we covered today? Different strategies can be used to increase food supply and we've looked at quite a few, haven't we? Strategies to increase food supply include irrigation, aeroponics, and hydroponics.

Biotechnology has a role, for example, the production of genetically modified crops that are drought or pest resistant.

And clearly, that drought resistance is gonna be important in the context of climate change.

A New Green Revolution is needed to increase the production of smaller farms without harming the environment.

And clearly, there are lots of organisations working on that.

We talked about that permaculture, didn't we? And intercropping.

Now, the Mwea irrigation scheme in Kenya, East Africa is an example of a large scale agricultural development designed to increase food supply.

Remember, we looked at that double cropping, but it has both advantages and disadvantages.

So well done for taking part in that lesson.

There was quite a lot to it, wasn't there? And we've looked at some real world examples, which hopefully brought it to life for you.

I look forward to seeing you again soon.

Well done.