5.3 Soil degradation and conservation

Question 1

outline how soil fertility changes throughout succession?

Answer 1

Initially, soil is little more than mineral particles, nutrient-poor with an erratic water supply.

STAGE ONE: simple soil starts developing from windblown dust and mineral particles.

STAGE TWO: invertebrate species begin to live in soil and increase organic matter (humus) content and water-holding capacity. Weathering enriches the soil with nutrients.

STAGE THREE: new species such as small plants and ferns colonise, soil continues to increase in organic matter content, water holding capacity and nutrient content.

STAGE FOUR: larger plants can grow in the deeper and more nutrient-rich soil.

STAGE FIVE:climax community dominated by shrubs and trees.

Question 2

explain how deforestation can affect soil fertility?

Answer 2

removal of forest increases soil erosion. The leaves of forest trees both deflect and slow down the progress of raindrops which helps stop them from removing soil particles. The root systmes of forests help to bind the soil together and give it stability.

Question 3

explain how intensive grazing can affect soil fertility?

Answer 3

overgrazing of grasslands leaves bare patches where roots no longer hold the soil together. When this is combined with rain and wind the bare patches become bigger and the soil is removed for the area.

Question 4

explain how urbanisation can affect soil fertility?

Answer 4

Land in cities is paved and built upon so removing it removes a source of agricultural land and increases run off which leads to ore erosion elsewhere. many citices have expanded into prime agricultural land.

Question 5

explain how irrigation can affect soil fertility?

Answer 5

In many irrigation systems, a mayor part of the water evaporates before reaching the crops. the minerals dissolved in the water remain on the top layer of the soil and form a hard salty crust (salinization) land is now unsuitable for growing crops.

Question 6

explain how monoculture farming can affect soil fertility.

Answer 6

the same nutrients are depleted from the soil leading to soil exhuasion. High yeilding viarities of crops require large amounts of nutrients to go and have a great impact.

Question 7

What are the processes of soil errosion?

Answer 7

sheet wash, gulliying and wind errosion.

Question 8

what is sheet wash?

Answer 8

large areas of surface soil are washed away during heavy storm periods and in mountain areas moving as landslides.

Question 9

what are gulliys?

Answer 9

chanells develop on hill sides following rainfall. Over time these channels become much deeper, increasing water flow.

Question 10

what is wind errosion?

Answer 10

on drier soils high winds continuously remove the surface layer.

Question 11

how do human activities affect sheet wash?

Answer 11

Sheetwash could result after a total removal of crops during harvest.

Question 12

how do human acitivies affect gullying?

Answer 12

Gullying could result from growing crops in rows with uncovered soil between, especially if the slopes are grown on a slope and rows are in the direction of the slope.

Question 13

how does agriculture affect wind erosion?

Answer 13

wind esorion will result from the removal of crops

Question 14

which farming practice tends to reduces soil fertility the most, industrialised commercial farming or small-scale subsistence farming? explain your answer.

Answer 14

Industrialised commercial farming will reduce soil fertility more due to soil erosion, exhaustion and toxification. This type of farm tends to grow monocultures which deplete the soil of nutrients and crops are completely harvested at the same time increasing soil exposure to wind and water.

Irrigation will be more intense leading to increased salinization of the soil and the overuse of pesticides will result in toxification.

small scale subsistence farming tends to grow a variety of crops, harvested at different times with less use of irrigation or chemical pesticides.

Question 15

Describe how soil conditioners can be used to improve soil quality.

Answer 15

Crushed limestone or chalk increases the PH and counters soil acidification.

Helps clay particles stick together so they act more like sand. (this helps with drainage, trapping air and aiding decomposition).

Organic materials improve the texture of the soil and act as a supply of nutrients (these are realsed slowly).

Question 16

explain how the terracing techniques are beneficial in conserving soil quality?

Answer 16

This reduces the steepness of the slope by replacing the slope with a series of horizontal terraces. these trap soil and water, reducing soil eruption.

Question 17

explain how the plowing techniques are beneficial in conserving soil quality?

Answer 17

breaks up soil structure and temporarily increases drainage. This makes a seed bed for sowing. However growing evidence suggest polowing is bad for soil structure and microbial activity.

Question 18

explain how the contour farming techniques are beneficial in conserving soil quality?

Answer 18

ploughing and cultivating along contour lines perpendicular to the slope. The furrows and ridges cut out as small terraces trapping soil and water (and water down hill), reducing erosion.

Question 19

explain how improved irrigation techniques may conserve soil quality?

Answer 19

Covering irrigation canals will prevent evaporation before the water reaches the land. Drip irrigation consists of a network of pipes covering the field. The pipes have small openings next to the plants so the p,ants they can absorb the drops of water before they evaporate. Both of these prevent salinization of the soil.

Question 20

explain how crop rotation may conserve soil quality?

Answer 20

growing the same crop year after year on the same land leads to pest and disease build up and impoverish the soil. Changing the crop grwon would allow the nutriet levles to recover. For example, planting Legumes between other crops woul add nitrogen to the soil.

Question 21

describe what is meant by the term Marginal lands and explain why their use must be considered carefully inorder to conserve soil quality?

Answer 21

marginal land is land that is found on the edge of cultuvaed areas and is often difficult to grow crops on. The soil is of poorer quality than the cultivated land and using it to grow crops would furthere deplete the nutrients nd increase the size of the marginal land.

Question 22

What is your researched soil management strategy for a named commercial farming system? Evaluate.

Answer 22

In 2025, British farmers will have access to an app that can help them record their soil analysis.

The app is called Soil Health Scorecard and is to be trialled on farms supplying UK supermarkets Asda and Tesco, and potato processor McCain, having been developed by agri-tech company Abaco Group.

The digital database will enable users to record soil sample results, and then offer advice to farmers on how to improve the quality of their soil.

The aim is to help farmers improve the targeted and efficient use of nutrients, increase yield resilience, reduce the need for fertilisers and provide better support for biodiversity.

McCain said Minimising soil disturbance is one of the core principles of its regenerative agriculture framework, which is promoted by the app and aims to see regenerative agriculture practices implemented across 100% of its potato acreage by 2030.

Question 23

What is your researched soil management strategy for a named subsistense farming system? Evaluate.

Answer 23

Instead of migrating to more fertile soils (nomadic farming), subsistence farmers in southern Zimbabwe are turning to an agroecology approach.
White commercial farmers had ranched cattle in the area prior to being pushed out during the reforms. The village has had soils categorised as loamy to sandy, and the new owners, who wanted to farm crops, experienced challenging conditions.

Some common agroecology approaches employed in the Shashe area include implementing crop rotations, diversifying crop species, integrating livestock into farming systems, employing organic farming methods such as the use of organic fertiliser, promoting natural pest control, mulching, soil fertility enhancement through techniques like composting, and green cover cropping.

A commitment to agroecology approaches had not only benefited local households but also inspired a larger movement towards a healthier future for their families.

Question 24

what are some strategies for increasing sustainability in food production systems?

Answer 24

organic farming, less pesticides and eutrophication, lower yields

polyculture instead of monoculture farming involves growing multiple crops rather than focusing only only one. Animals and plants, labour labour-intensive, and not done on a large scale. May have to import fish and ducks, if they get out they may be an invasive spcies.