Constant irrigation leads to salinisation of soil, how this happen is the water contains minerals (salt). When the water evaporates or used up by the plants, minerals (salt) are left behind on the soil.
Over time, the mineral (salt) build up and causes the soil to be too salty to grow. Imagine drinking saltwater everyday, you will end up looking like dried fish!
Irrigation (problem 2)= waterlogging
The other problem is when the soil is soaked up with too much water and the water can flow into ground anymore, this will lead to flooding.
Chemical fertiliser = eutrophication
As shown in class, when there is too much nutrients flowing from farmland to the river during rainfall, the nutrients are absorb by the algae living in the water, this leads to an algae bloom. When the nutrient level drops, alot of the algae will die, leading to a sharp rise in CO2 and excess nutrients in the water, this could also lead to poisoning of the water. This in turn will kill the ecosystem in the river. Textbook not very accurate.
Chemical pesticide and hebicide = water pollution
Like fertiliser, this also gets washed into the river. Take a guess what happens after that. Not sure? Go drink some pesticide and then tell me.
GM food = Potential health issues
We are not completely certain that GM food are the cause of concern on a large scale. However some modifications can cause allergy. Saying that, almost 90% of the food you eat are GM.
GM food = loss of biodiversity
Big issues rising from GM food is that plants can cause cross pollination with local plants that could make them pest resistant, meaning insects that are native to the area will die over time. In time animals that depend on the insects for food or other plants need them for pollination will suffer in decline. This is known as gene pollution.
Worst, the plants become superweeds, this makes them a pest plant as it is becomes very hard to remove them.
On the financial aspect:
GM food are not cheap!
This means LDC will have problems implementing them with government or international support establishing and maintaining GM food production in the early years.
Another issue rises when LDC are able to produce GM food, they are mainly producing cash crops such as coffee, oil palm and the likes. This becomes an issue as the locals that work in the agricultural sector will not have or afford a balanced diet. The lack of education in getting a balanced diet also comes into play. This will lead to malnutrition.
CHECK page 283 to 285 of your textbook! THAT IS AWESOME STUFF! just take my information on eutrophication from my blog.