Module 3: dynamics in Soil Fertility Flashcards
What determines soil fertility?
A fertile soil is capable of supplying the nutrients essential for plant growth to the plant roots.
Another aspect, is soil structure which in turn affects water holding capacity.
What is Law of the Minimum by Justus von Liebig?
The Law of the Minimum relates to a barrel that can never fill up more than the lowest side, the water will always drip out. Plant growth similarly is limited to the nutrient that the plant is deficient in.
What are nutrient surpluses? Provide example of environmental consequences.
A nutrient surplus occurs when more nutrients in the form of chemical or animal mature fertilisers are applied than harvested in the crop.
What are ways to reduce phosphorus losses from agricultural soils?
What processes cause decreasing soil fertility?
?? Predict the loss of soil fertility by applying a simple soil model.??
What are nutrient essential for plant growth?
A nutrient is a chemical element and is essential when
- a plant cannot finish life cycle without it.
- the nutrient has a direct role in the plant’s metabolism and it cannot be replaced by another element.
What consequences do nutrient deficits have?
Lower crop yields as well as decreased nutritional value.
What nutrient deficiency do leaves with the following colour indicate?
- yellow-green coloured?
- purple ends?
- nitrogen, or other elements
- phosphorus
What is a big responsibility of the element nitrogen?
Photosynthesis.
What is at the root cause of nutrient deficits?
Rarely is it the ability of the plant to take up nutrients. More often it is either the total amount of the element in the soil or the available amount in the soil.
What can be a cause of low available nutrients for plants in the soil?
The pH of the soil is not at an adequate level.
What are the environmental consequences for a nitrogen surplus?
Nitrogen can
- leach into the ground water
- cause disappearance of fragile plant species when ammonium volatilises into the air and deposits close by
- it can escape as nitrous oxide into the atmosphere contributing to global warming through green house gasses.
What are the environment consequences of phosphorus surplusses?
Phosphorus leaches into the groundwater. In Western Europe this often leads to eutrophication. This is a bloom of algae in open water sources which leads to disappearance of other plants and animals.
What is soil organic matter?
Dead organic matter of plants in the soil, another word is humus. It is food for soil organisms.
How much carbon is stored in the ocean versus land? How much of the terrestrial carbon is stored in the soil?
The ocean stores ten times more carbon than the soil. Yet of the terrestrial carbon, soils are the largest sink.
