Agriculture and food - applied science

Harvests are when a produce is collected so that it can be used, they're two types of harvests, these are:

• Gathered harvests: this is when a microorganism is kept alive and their produces and collected to be used, for example milk from a cow, wool from a sheep or fruit from a plant.
• Whole-organism harvests: this is when the microorganism is used or consumed, for example meat from an animal or using whole plants, e.g. sugar beet.

Living organisms aren't just used for the consumption of humans, they are also used for other tasks and products, for example:

• Producing fuels for transport - sugar beet and microorganisms help to produce gasohol, microorganisms produce biogas and vegetable oils produce biodiesel.
• Waste treatment - microorganisms' are used in sewage treatment.
• Food processing - bacteria is used to make some of our foods, for example it is used to make yoghurts and cheeses.
• Environmental management - this is also known and biological control, this is when predators are used to try to control pests.

Agriculuture is another word for farming, they're five main types of agriculture, these are;

• Arable farming, this involves growing crops for humans and animals to consume and also growing crops for other products such as producing biodiesel. People working on these kind of farms do these kind of jobs:

--> Ploughing - this involves turning the soil over and sometimes adding fertilizer    in order to prepare the soil for the planting of the crops

--> Agricultural engineering - this involves looking after the farming equipment, such as the combine harvesters or the tractors.

--> Planting, irrigating and harvesting - this means planting the seeds, watering the crops and collecting the produce.

Another type of agriculture (or farming) is horticulture, this is:

• Growing plants and flowers for gardens, the work types are similar to arable farming, such as ploughing, planting the seeds and harvesting the produce, but it has other slightly different jobs such as: collecting and storing seeds.

Another type of agriculture is:

• Beef Cattle, Sheep and Pig Farming: this involves rearing the cattle, sheep and pigs for meat and other products such as wool or milk. Jobs at these types of farms would include:

--> Feeding and looking after the animals

--> Shearing sheep on 'sheep farms'.

Dairy Cattle is another type of agriculture, on these farms:

• they produce milk, which is then used to make milk products such as cheese and yoghurts. Jobs on a dairy farm are pretty similar to those on a cattle, sheep and pig farm, they include

-->Milking the cows.

--> Maintaining the equipment that is used in the process of milking a cow.

The last type of farming is called Poultry Farming, here they:

• Keep domesticated birds, such as chickens, turkeys and ducks. They keep them for their production of food and eggs. The jobs at these farms include: Feeding the birds, slaughtering the animals and collecting the eggs, some of these jobs are carried out by hand, some by machines.

The chain of food production - from the farm to your fridge:

1. Growing - crops and animals are grown on farms, whereas microrganisms are grown in fermenters in factories.

2.Transporting - the harvested product may be transported from the farm to another site for processing.

3.Processing- the product may need to be processed, for example milk needs to be pasteurised. Microorganisms can also be used in processing.

4.Storing - if not all the processed product is required right away, then some of it is stored until it is needed. Supermarket chains store goods at large distrubution centres before they need them.

5.Delievering - this is the process where the food is delievered to your local shops for you to take home and consume.

Biotechnology is the process of using microorganisms during food processing and production, for example:

• Yeast is used in the brewing industries to make alcohol
• Yeast is also used to make bread
• Bacteria is used to turn milk into cheese and yoghurt
• Fungi make mycoprotein - a meat substitue for vegetarians.

Basically, it just means using a microorganism to help produce and food or to help with the process of turning something into a food.

Agriculture and Food Production has to be regulated, this is because of the following reasons:

• Health and safety: farms and factories involved in food production have to be checked regularly so that they can see that they are wokring in a safe manner and the health of the workers is being considered.
• Animal welfare: by law, animals have to be treated humanely, this includes on farms, at slaughter houses, at the market and during transportation.
• Environmental protection: some fertilizers can be harmful if they get into the water system, therefore farms have to have their methods checked to ensure they are not harming the environment.

Two organisations regulate agriculture; defra and fsa.

• Food Standards Agency (FSA) was set up by government but is independent of it. They help regualte production, storage and transport of foods to protect consumer interests and public safety.

The other organisation that regulates agriculture is DEFRA.

• This stands for: 'The Department for Enviornment, Food and Rural Affairs', this is the government department responsible for farming and food production. Defra looks after everyone involved in farming, agriculture and the environment and consider there ideas to work towards sustainable development.

Enforcement Officers monitor the Food Chain. They work for many organisations and are there to ensure rules and regulations are being carried out throughout the food chain. For example:

• Factory inspectors: making sure that workplaces stick to health and safety rules.
• Enviromental health practitioners: they visit factories, shops, restaurants, houses and offices to ensure they're safe and hygienic. They are allowed to wihtdraw products if they endanger the publics' health. They also monitor pollution levels to help protect the environment.

There are some organisations that support the food industry, they help to promote particular parts of the food industry and carry out research and provide practical advice to the producers in that part of the industry. For example

• 'The Milk Development Council', they run marketing campaigns to help promote milka nd dairy products to the public, therefore help dairy farmers increase their profits.
• 'The British Potato Council', this is funded by potato producers and commercial potato buyers, they help to advertise and promotes potatos both in the UK and abroad.
• 'The Meat and Livestock Commission', they help to promote British meat in the UK and abroad and they aim to improve the efficient of the UK's livestock industry.
• ADAS - gives advice on all aspects of farming, for example animal welfare.

There are lots of plants that produce food, in other words they don't require any processing. This is for both animals and humans, for example:

• For humans: Apples form orchards, Lettuce and Potatoes.
• For animals: Grass, Silage to feed cattle over the winter and Hay.

However some plant materials have to be processed before it can be used for anything, some examples of these plants are:

• Sugar beet is used to make sugar. After it is harvested it is sent to factories to be cut into chips and put in tanks of water. The sugar then leaks from the chips into the water. The chips are removed and crushed so all the sugar juice is squeezed out of them. The sugary water is then filtered and evaporated leaving behind sugar crystals that are then packaged and sent to supermarkets.
• Flour - grains from cereal crops are ground between stones or steel wheels to produce flour, this is called milling. Which part of the grain that are milled determines the type of flour produced e.g. wholegrain or white.

Another type of plant that has to be processed before it can be used is vegetable oil:

• Vegetable oil can be extracted from plant seeds (e.g. sunflower or **** seeds) or fruit. The plant material is crushed and squashed and the oil is seperated, however the oil can also be extracted chemically.

Plants provide other useful products:

• Materials: wood from trees makes furniture and paper
• Fibres and fabric: cotton from the cotton plant and linen form the flax plant
• Biofuels: these are fuels that're made from biological products, for example ethanol can be produced from the sugar extracted from sugar beet and biodiesel can be made from the oils processed from vegetables.

The Life-Cycle of a Flowering Plant has Five Main Stages:

• Pollination: this is the transfer of the pollen (the male sex cell) into the female part of the flower, for example by insects.
• Fertilisation: The male and female sex cells join together.
• Production of seeds and/or fruit: The seed is formed and in some plants the fruit develops around the seed.
• Dispersal of seeds and/ or fruit: Small, dry seeds are blown away by the wind and fruit can be eaten by animals, so then seeds are dispersed and scattered around by their poo.
• Germination of seeds: The seed starts to grow into a new plant.

Often seeds will lie dormant until the conditions are right for germination. The three things needed for seeds to start germinating are; water - to activate enzymes that break down the food reserves in the seed. Oxygen - needed for the process that provides energy for growth. A good temperature - this is needed to allow the enzymes to begin working, however this depends of the type of seed that needs to be germinated.

Photosynthesis is needed for plant grow because it allows the plant to produce food in the form of glucose. Four things are needed for photosynthesis, these are:

• light: this is usually gotten from the sun
• chlorophyll: this is found in the chloroplasts and is the pigment that makes the leaves look green. This is the 'magic stuff' that makes the photosynthesis happen. It absorbs the energy in the sunlight and uses it with carbon dioxide and water to produce the glucose, oxygen is also made as a by-product.
• carbon dioxide: this enters the leaf from the air.
• water: this comes from the soil through the roots and travels up the stem into the leaf.

this is the equation for photosynthesis:

carbon dioxide + water --> glucose and oxygen

Some farmers artificially create the condiitons needed for photosynthesis because sometimes the things needed for photosynthesis aren't naturally there in the right amounts. These are done in glasshouses ( big greenhouses) or polytunnels.

1.Farmers used artificial light supplies and the sun goes down so that photosynthesis can continue to occur.

2.Farmers can increase the levels of carbon dioxide in glasshouses by burning fuels, because carbon dioxide is a by product of this.

3.Keeping plants enclosed in a glasshouse keeps away natural predators so keeps the plants free from disease.

4.Glasshouses trap the sun's heat so the temperature continues to be high.

5.These conditions are used so that the farmers can produce more high quality plants more often.

Pests can reduce crop yields ( the amount of crops that are harvested ) by damaging seeds, fruits, flowers, stems, leaves and roots.

• They may damage the actual harvest, for example the fruit. This means they have to be thrown away
• They can slow the growth of crop, by damaging leaves which means less of the crop grows.
• They spread diseases between plants when collecting nectar and pollen.

If a pest gets into a farmhouse it causes many problems, because it's warm and there's lots of food around. To get rid of these you can use chemcials or predator organisms. Chemicals use pesticides to kill pests and natural predators can also be used.

For example, aphids eat roses and vegetables, ladybirds are aphid predators, so are released into glasshouses to keep the number of aphids down.

Chemical control vs Natural predators: advantages and disadvantages

Chemical control advantages and disadvantages:

• Cost efficient
• Easy to apply to plants
• Could remain on food
• Could kill harmless, useful insects, e.g. pollinating insects

Natural predators advantages and disadvantages:

Less poluting, usually only affects pest animal. Wont kill all pests, takes management and training, predators could escape into the natural environment.

Wet mass is the mass of all fresh plant material (including all the water in the plant tissues). Potato and pea yields are measured as wet mass.

Some crops are measured by dry mass, this is when the water is removed from the plant tissues before it is weighed. Tea and cereal grain yields are measured as dry mass.

Yields are usually measured as the amount of harvestable material produced from one plant or from an area.

Generally, the growing media for plants is soil, sometiems compsot is added to improve the soil. However, plants can be grown without soil using a process called hydroponics, this is when the plant is grown in a nutrient solution instead. The nutrients contain everything a plant needs to grow, these are:

• Water: needed for photosynthesis and is taken up through the roots of the plant.
• Nutrients: help the plant to grow , e.g. nitrates, phosphates and potassium help good root, shoot and flower growth. This is also taken up by the roots
• pH: the availability of the nutrients in the soil depends on the pH of the soil, this is because different plants grow better in different pH's, for example, potatoes grow best is slightly acidic soil, whereas sugar beet grows best in netural-slightly alkaline soil. 

Good soil:

• contains a lot of nutrients, the nutrient content of soil can be omproved by mixing in compost, which is high in nutrients.
• sometimes, farmers add fertilizer to aid the plant's growth.
• holds water and nutrients, therefore making them available for the plant to use, how well a soil does this depends on:

-The soil structure: good soils are a mix of clay, slit and sand.                                 -The humus content: humus is a natural compost that is made of decomposed animals and plants. Therefore the higher the humus content, the higher the nutrients.                                              

• A good soil supports the plant so that it doesn't blow over or fall over.

Hydroponics is literally the process of growing a plant in a nutrient solution. A nutrient solution is a mixture of water and fertilizers. Tomatoes and cucumbers are grown using hydroponics.

Advantages:

• Less land is required and no soil preparation and weeding is required.
• Plants can still grow in places with bad soil
• Most pests live in soil, so hydroponics avoids these.
• Mineral levels can be controlled accurately.

Disadvantages:

• It can be expensive to set up and run and growers need skills and training.
• Plants need support as there's no soil to anchor the roots
• Specially formulated soluble nutrients have to be used. 

Genetically identical plants can be produced from a process called 'cuttings'. You do this by:

• Snip off parents of the 'parent' plant, usually a stem with leaves on and pot them up.
• Each cutting will grow into a new plant that is genetically identical to it's parent.
• Plants are produced quickly, and cheaply.

However, there are pro's and con's to producing identical plants, these are:

• You are sure of the characteristics, so each plant will be good quality
• You can mass-produce plants that are naturally difficult to grow.
• No fertilisation or pollination is need to produce seeds for new plants
• The main drawback is a reduced gene pool, a reduced gene pool means less alleles (variations of the same gene pool). Therefore if a plant catches a disease, it is possible it can wipe out the entire plant or animal because they are identical and are not resistant.

Tissue culture is also used to make genetically identical plants, for this you:

1.Remove a small amount of tissue from the 'parent' plant, you only need a tiny amount and this is normally taken from the fast-growing roots or shoot tips.

2.Then you grow the tissue in a culture of nutrients and growth hormones, you also do this under sterile conditions so that microbes cannot harm the plant tissue.

3.As the tissues produce roots and shoots then are transferred to potting compost to carry on growing

Animals provide use with food, textiles and fertilizers:

• food: they produce milk, eggs and are meat as well as contributing to dairy products
• textiles: leather (from animal hides) and wool from sheeps.
• fertilizers: manure from animals or using the animals bones for ' bonemeal'.

Some animals are processed before they can be used, for example:

• Slaughterhouses: the animals are transferred from the farmers onto slaughterhouses where they go through stages of processing, these are: stunning and slaughtering the animals, removing and skin or feathers, inspecting the carcass to ensure it is safe and a good quality and then breaking down the carcass.
• It is then sent to the butchers, where the cuts are prepared and sold.

Farmers need to know what animals need in order to grow. These are:

• warmth: this way the animals waste less energy keeping warm so therefore grow faster.
• shelter: animals grow faster if they have a shelter to keep them warm.
• food and water: both food and water provide the animals with energy to grow.
• Good health: pests and diseases can weaken the animals meaning either they grow slower or die.

If you are asked to interpret data on the best techniques or feeds used to promote an animals growth you just need to look at the changes of mass in the animal.

Intensive farming: this is when animals are kept in limited spaces in controlled conditions of temperature, ventilation and light so that the animals don't have to waste energy moving around and keeping warm so therefore can grow faster on smaller amounts of food. They are also sometimes feed growth hormones in their concentrated feeds to promote their promote evenmore.

However, intensive farming has a few ethical issues surrounding it. These are:

• People think forcing animals to live in such unnatural conditions is cruel.
• The crowded conditions the animals live in are a favourable place for disease and illness and, because of the crowded conditions, it spreads quickly. An example of a disease in these places are foot-and-mouth disease.
• Sometimes if the animals are kept in crowded conditions in can cause they to become stressed and it is deemed as unethical.

Organic farming is a more traditional way of farming, unlike intensive the animals are allowed to roam free in big spaces and are fed organically grown food, however, because the yields are lower, the food is more expensive.

There are pro's and con's for organic farming, these are:

• Organic farming uses less chemicals so there is less risk of toxics being left on food.
• Follows the guidelines of how to ethically treat an animal

• Needs more space, so more land is farmland rather than wildlife.
• More labour-intensive: provides more jobs but is more expensive.
• can't grow as much food as intensive if they had the same amount of land.

Sexual reproduction in a mammal has five main stages:

1.Formation of gametes: The male and female sex cells, called gametes are formed.

2.Fertilisation: The male and female sex cells join together inside the female to form a zygote.

3. Internal development: The zygote develops into a fully growth fetus.

4.Birth: When the fetus has developed enough, chemical signs star the birth and the baby is born.

5.Growth and development: The baby grows and develops into an adult mammal.

Reproduction can also be carried out through a process known as artificial insemination, this involves four stages

• Selection of animals: animals with good 'characteristics' e.g. high milk/meat yield, good fertility etc. are chosen to mate
• Collection of sperm: The sperm is collected in a device with stimulates the male to ejaculate and then keeps the sperm at a good temperature
• Storage of the sperm: The sperm is checked for quality to ensure fertilsation and is then transferred to plastic straws where it is frozen in liquid nitrogen until it is needed.
• Insertion of the sperm: A long pipette with the contents of the straw is inserted into the cow, this has to be done just before the cow releases an egg to have a greater chance of fertilisation.

Artificial insemination has advantages over natural mating, these are; reduced cost: it is safer and cheaper to buy the sperm rather than the male animal, decreased risk of disease: sperm is checked, therefore they can notice any STI's, increased quality: sperm is from a known, high quality bull.

Selective breeding is used in farming, this is when cattle or plants are chosen to mate based on the characteristics we want the offspring to have, this is also known as artifical selection. Here are the basic stages:

• From the existing stock the cattle with the 'best' characteristics are chosen to mate
• The best of the offspring are selected and bred.
• This process is repeated many times through many generations to ensure the genrations develop the desired traits, these traits are normally things like: high yield of milk, meat, grain etc., good temperament and fertility, good appearance/ smells for plants and good health and disease resistance.
• The only drawback of selective breeding is the reduced gene pool, this occurs because of the inbreeding.

Generally farmers only breed their best animals. Traditionally, farmers only allowed their prize female to produce one offspring per year. However this process has been transformed by embyro transplants:

1.Sperm and egg cells are taken from the prize winning cattle.                                  2.The sperm artificially fertilises the egg.                                                                   3. The fertilised egg divides and ends up having a ball of genetically identical cells, which then develops into an embryo.                                                                         4.The embryo is split into seperate cells and each grows as a new embyro, all clones of the original one.                                                                                          5.The embryo's are implanted into lots of females, called 'surrogate mothers' and they are grown, however they can also be frozen and used later if needed.              6.The offspring are clone's of one another, not their parents

Advantages: Hundreds of 'ideal' offspring can be produced every year from the prize winning male and female, and the female can continue producing eggs.

Disadvantage: Reduced gene pool.

Microorganisms helps use to make lots of useful products. Microorganisms are bacteria, fungi (including yeast) and viruses. Here are how they help us:

• Food: e.g. cheese, bread, yoghurt and mycoprotein
• Alcohol: for drink or petrol e.g. ethanol- which is mixed with alcohol to produce gasohol.
• Enzymes: e.g. chymosin, used for cheese making

Microorganisms convert sugar into other substances duirng respiration, there are two types: aerobic and anaerobic. In an industry this process is called fermentation.Microorganisms need the right conditions in order to ferment, for example:

• food sources
• right temperatures
• and oxygen if they are respiring aerobically.

Some products are made from the microorganisms themselves, for example mycoprotein. However others are a product of the microorgansim, for example yeast extract. Microorganisms grow faster by aerobic respiration. The equation is:

• sugar + oxygen --> carbon dioxide +water

Mycoprotein is a fungi used to make meat substitutes for vegetarians, for example quorn. This is how it is made:

• The fungus is grown in fermenters using sugar for food. The sugar is obtained by digesting maize strach with enzymes.
• The fungus respires aerobically, so oxygen's supplied together with nitrogen and other minerals. The mixture also maintains a correct temperature and pH.
• When the fungus has grown, it is extracted and dried.
• It is then processed even further by adding flavourings and other ingredients.

Anaerobic Fermentation is used when making bread. This is because the yeast produces carbon dioxide when it ferments anaerobically. The equation for this process is:

• sugar --> ethanol + carbon dioxide

1.Grains are milled to produce flour

2. Yeast and sugar are added to the flour to produce dough

3. The yeast feed on the sugar, producing carbon dioxide that makes the bread rise.

Anaerobic fermentation in bacteria helps use to make some dairy products, such as cheese and yoghurt. This is because anaerobic respiration produces lactic acid. the equation for this is:

• sugar --> lactic acid

Making cheese:

1.A culture of bacteria is added to warm milk

2.They turn the sugar in the milk into lactic acid, which causes the milk to curdle.

3.Enzymes (e.g. chymosin) are often added to help produce solid curds in the milk.

4.These curds are seperated from the liquid whey.

5.The curd is left to ripen for a while before it's processed.

Yoghurt is basically a fermented milk, this is how it is made:

1.Milk is pasteurised (heated) so that any unwanted microorganisms are killed. All the equipment used is sterilised and the milk is then cooled.

2.A culture of bacteria is added and the mixture is incubated (heated about 40C) in a fermenter.

3.The bacteria turns the sugar in the milk to lactic acid and causes the milk to clot and solidify into yoghurt.

4.Flavours and colours are sometimes added before the yoghurt is packaged to make it look more appealing.

Large amounts of useful proteins from microorganisms can be produced if their genetic material is modified. This is done by

• Selecting a gene from a useful protein and adding it to the genetic material of another organism.
• This genetically modified organism can produce the useful protein as well.
• If you grow large amounts of the genetically modified organism, then you get large amounts of the protein too.

Chymosin:

This is a enzyme used in cheese making, it clots the milk to help the production. Scientists have genetically modified yeast so that it also produces this enzyme.

Chymosin is traditionally taken from the lining of a calf's stomach - so by using chymosin from genetically modified organisms, cheese suitable for vegans can be produced.

Sometimes microorganisms such as bacteria and fungi 'go off' and this causes food spoilage. This can be spotted in many ways, by:

• Visible growth such as mould on bread

However, food spoilage is also caused by waste products. Microoragnisms can break down the food and feed on it, this produces waste products that can contaminate the food.

With some microorganisms, if you digest them, then you can become extremely ill and get food poisoning. Of course they can cause other illnesses too, such as flu virus. To make sure these things dont happen, you have to avoid getting unwanted  microorganisms into the food production. If you do allow this to get into the food production dangerous microorganisms can grow in the contamination.To avoid this, equipment is sterilised and clean. You can also heat and use chemicals to kill unwanted microorganisms and make sure you food is safe.

There are three ways to measure the number (or population) of microorganisms in samples:

Colony counts:

• A sample of the stuff you're growing is diluted and spread over an agar plate. This is incubated to allow microorganisms to grow.
• Each microorganism produces a colony ( a clump of cells). By counting the colonies you can calculate how many microorganisms were in the original sample.
• If there are too many colonies to count, repeat the process with a more diluted sample.

Biomass:

• The amount of organic material (biomass) in a smaple is weighed. The biomass gives an indication of the number of microorganisms growing.

The last way to monitor the number of microorganisms is a process called turbidity:

• This is a measurement of the cloudiness of a liquid - the more cloudy it is, the more microorganisms there is in the liquid.
• The amount of light that travels through the liquid can be measured. The more cloudy it is, the less light can pass throughit, and this gives an indication of the amount of microorganisms.

Safety and Quality of food is very important to consider. If the food isn't safe it could cause food poisoning and if it isn't of a good quality customers won't buy it.

There are three types of testing techniques, qualitative, semi-quantitative and quantitative.

Qualitative: These tests generally give you a yes / no answer, they don't provide numerical data.

• You can tell if a plant lacks a mineral by looking at it, e.g. if a plant doesn't have enough nitrogen it will have stunted growth and yellow, old leaves.
• In brewing you can see when the fermentation is complete when you the gas bubble production slows down.
• If you are inspecting a crop for damage you can gain a good understanding of it's quality.
•  Quality of dyes are determined by their colours and..
•  You can see whether it has gone off because it'll look green, mouldy, furry etc.

Semi-Quantitative: These tests give you an estimate of something, but are not as accurate as quantitative tests. E.g.:

• Soil's pH can be identified by usingtest strips to indicate pH to 1-2 units.

Quantitative: These tests give an accurate measure of something:

• Soil pH can be measured accurately using a pH meter than measures to 0.1
• The level of alcohol in beer can be measured using a hydrometer.
• Percentage of germination rate (a measure of seed quality) can be determined by growing seeds.
• The concentration of dyes present in foods can be measured in colorimeter.
• Carbohydrates and protein levels in cereal grains can be measured by using chemical tests.

Prices of food can be affected by different factors, these are according:

Supply and Demand:

• The amount of a product that can be bought (supply) and the amount people want to pay (demand) affects the price of the product. 
• If there is more of a product than wanted , so basically there isn't enough demand for it, the product is cheaper.
• If theres an increase in demand and not enough product (supply) then it'll be more expensive.

Government Intervention also affects the price of a product:

• The government provides money (known as subsidies) to the producers in some industries,
• Subsidies are given to ensure products are continuously made in the UK, because it provides jobs and if not UK industries would be outcompeted.

Marketing products let people know what products are available to buy:

• Producers can use advertising to tell you about their product
• They can make their products look nice - therefore people will buy them.

Quality marks indicate certain standards:

• Quality marks let you know the product you're buying has reached certain standards. E.g. The lion quality stamp on an egg indicates that the egg has come from a hen that has been vacinated against salmonella.
• Soil Association Organic Standard - this shows food has been processed to strict organic standards.

These quality marks increase the market value for a product, simply because people are more willing to pay for products that they know are safe and of a good quality.

Sustainable agriculture : farming that follows the production of crops or livestock without damaging the environment. Basically we make sure we farm responsibily so that we don't ruin things for future generatons.

Quality of soil needs protecting because it is vital to farming:

• Plants take essential nutrients from soil to grow and reproduce.
• When plants die, they're broken down by microbes - so nutrients are returned to the soil, fro other plants to use.
• If plants are taken away by the farmer, then the nutrients are also taken away.
• This means nutrients aren't naturally replaced so farmers use other methods:

- Planting legumes: plants put nutrients back into soil as nutrient compounds. Longer these crops are growth the more nutrients are put back into the soil.           - Fertilizers: these put nutrients back, but make sure they aren't harmful.

Non-renewable resources are natural resources that will eventually run out. These include some fuels and chemicals used to make synthetic fertilizers and pesticides. Farmers should reduce their dependence of non-renewable resources by:

• Using renewable resources, such as wind, sun and waves or natural fertilizers and using less fuel, synthetic fertilizers and pesticides

Farming can also have harmful affects on the environment, if they use harmful things such as: using too much fertilizers can cause it too run into rivers and kill the fish, pesticides can build up toxic levels in predators and also farming destroys natural habitats and wildife, to reduce this damage farmers can:

• Growing hedgerows between fields to provide a valuable habitat for wildlife, especially insects and can reduce soil erosion.
• Farmers can also set aside large areas of land and field and not actually use them for farming.