(2) Zero Hunger Mycorrhizas

Sophie Nixon

What are the major agriculturally-driven sustainability issues

• Domestication of livestock → large GHG emitting slaughterhouses

• Landscape modification → destruction to local ecology and hydology

• Policy incentives → not globally uniform thus different pollutant acceptable levels

• Crop breeding → reduced genetic pool = disease easier spread

• Efficient tools & machines → pullutants

What are the underpinning mechanisms that lead to soil degradation 

• Grazing → removal of essential nutrients (NPK)

• Biomass removal → reduced water hold capacity, nutrient and biological activity

• Tilling → altered ‘physical’ soil properties

• Erosion → complete soil removal

What can be done to mitigate soil degradation 

• hand harvesting instead of tillage

• strip cropping to preserve soil nutrient

• complimentary crop planting of variety of plants to increase water capacity and hardiness

How do plants get resources 

Absorbing nurtients (NPK) through the soil

• nitrogren produced from denitrification

• symbiosis between plants and fungi/bacteria (or both)

What is denitrification and was affects its usefulness

nitrate reduction which turns N2O (GHG) into N2 (harmless nitrogen gas) through anaerobic/near-anaeroic processes preformed by a large diversity of organism

dependants:

• temperature

• soil moisture → prefers 60-100%

• soil redox

• substrate availability

• pH → low

Partnerships: mutualistic relationships between plants and other organisms  

• fungi

  • mycorrhizas

  • Abrbuscular mycorrhizal fungal (AMF) inoculum

• bacteria

  • denitrification

  • Fabacae/Leguminosae relation

What are mycorrhizas and their function

fungal colonies on roots which can be found on species 90% of plant species

mycorrhizal fungal hyphae reached to larger surface area in the soil and are able to access inorganic phosphurus which can transfer additional nutrients to plants assisting growth

types of mycorrhizas

Arbuscularr mycorrhizal (AM) fungi

• for wheat and beans

Ectomycorrhizal (ECM) fungi

• they have a fruiting body (sporocarp) and large mycelial networks

• in 3% of land flora → in boreal, north temperate and dipterocarps

  • boreal take uo more organic nitrogen resulting in a highly conservative nitrogen cycle

• found in plants from 2cm - 100m high

Discuss the mutually beneficial relationship with bacteria and Fabaceae/ Lugeminosae

bacteria can fix nitrogen and convert to ammonia which is catalysed by a nitrogenase enzyme

found in soybeans, lentils, peas, chickpeas as bacteria forms ‘nodules’ on roots

discuss AMF inoculum

Arbuscular mycorrhizal fungal inoculum is the introduction of AMF to the ~15% of plants which have evolved to not associate with microorganisms to aid growth

it is not widely used due to:

• expensive

• lack of technical knowledge

• context dependednt effectiveness

  • paper conducted to show there is a correlatio of growth for wheat with innoculation when rotation and tillage is used by not corn

  • how effective?