Agroecology Flashcards
(25 cards)
Food security
The reliable supply of food
Issues threatening food security
Geopolitical unrest
Climate change
Human population growth and food expectations
Ecological and environmental effects of agriculture
Ecological consequences of agriculture
- Taking up more space- habitat change/destruction
Almost 90% of the world’s animal species will lose some habitat to agriculture by2050
-environmental effects of ag-chems.
- collateral effects of agrochemical use
The active sites pesticides target are taxonomically generic: i.e. they work on most/all insects, fungi etc.
Agrochemicals
Fertilizers
Pesticides
Neonicotinoids
class of neuro-active insecticides chemically like nicotine, developed at Shell and Bayer in the 1980s. Are among the widest-used insecticides in crop protection. Are also widely employed for veterinary purposes including tick and flea control.
usually used as seed treatments to protect seeds and young plants from various insect pests.
Compound integrates into plant tissues for a while as it grows
Why are neonicotinoids insecticides useful
1: Allow farmers to control damaging pests and therefore protect food supplies and farmer livelihoods.
If yields fall, food prices will rise and increase food insecurity.
2: Seed dressings control only the insects eating the crop, not those which use the crop as a habitat.
3: Reduce the need of farmers to spray insecticides onto crops: spraying will affect all insects over a larger area.
Issues with the use of neonicotinoids
Food source depletion
Direct poisoning
Leaching
Translocated to nectar and pollen where they can be consumed by pollinating insects
Effect of agrochemicals on soil microbiome
No effect on number of taxa
But types and abundance are affected
Glyphosate
Broad-spectrum systemic herbicide and crop desiccant
Main ideas to balance the need for food and environment
Soil management
Alternative fertilisers and pesticides
GMO crops
Land sharing v sparing
Rewilding/nature recovery
Conservation/sustainable/organic agriculture
Proactive climate change agri-interventions
Soil microbial carbon use efficiency (CUE)
Dictates how much C is stored vs lost to atmosphere
CUE: The ratio of carbon that is used to derive energy (via catabolism) verses build biomass (anabolism) by all microbes in a soil sample.
Soil management and alternative fertilisers
Cover crop = green manure
Overwinter/fallow
Between crops
Bioprospecting for microbes that can replace artificial fertilisers
Potential benefits:
Reduce N2O emissions
Reduce runoff
Reduce N-fertiliser used (and the impact of manufacturing these)
Reduce costs
The idea is to find plant ‘probiotics’:
Microbes that prevent pathogens establishing by occupying niches (exploitation competition) and/or by interference competition.
Classic plant breeding
Slow and relies on existing gene pool
GM crops
Potentially quicker and can use any genetic material – e.g. genetically engineer insect-resistant plants by incorporating genes that produced insecticidal proteins from Bacillus thuringiensis (Bt)
Have also engineered herb and pesticide resistance into crops (thus not affected by sprays)
Land sparing
focuses on maximizing agricultural production on some land and dedicating other land to conservation
Production and conservation in distinct areas
Production intensification
Less land allocated to production
More inputs to agricultural production
Mono-cropping
Land sharing
integrating agriculture and biodiversity conservation on the same land
Conservation in agricultural areas
Agricultural production benefits from ecological systems
More land allocated to agriculture
Less inputs - self-sustained agriculture
Diverse or associated crops
Is land sparing or sharing better
Sparing
Rewilding / nature recovery
Rewilding is essentially stopping any/most management interventions: letting it go…
It differs from more traditional conservation or restoration approaches in its focus on reducing human interference and restoring ecosystem functioning through self-regulation
Not a solution for food security as there is no agricultural production, unless this is part of a ‘land-sparing’ strategy’.
Is a solution for biodiversity gain and ecosystem services
Conservation agriculture
sustainable farming approach focused on protecting soil, improving its quality, and optimizing yields while minimizing negative impacts on natural resources and biodiversity.
How does climate change threaten agriculture
Changing temperatures and rainfall
More extreme events
Directly affects crops
Changes susceptibility to pathogens
Changes the types of pathogens
Effects of increased soil salinity
salinity damages soil structure, reduces organic availability, fertility and crop yields.
Bacteria and fungi: key drivers of soil nutrient cycles and fertility
Limited work shows short term negative effect in soil microbial respiration and activity, and there are only 4 studies analysing the effect on the composition of microbial communities.
-> effects of changes in salinity on soil biological communities are not well understood
SoilSalAdapt
the deliberate sustained use of part-saline irrigation across the growing season will apply a selection pressure resulting in soil and rhizosphere biological communities becoming adapted to be more robust and resilient to increased salinities predicted under climate change
This work:
Provides a useable on the ground pro-active agricultural intervention for growers to protect yields in the face of climate change
Addresses climate-smart sustainable management and the application of practices to protect soil and enhance its performance
Is the first attempt to conduct large scale ‘experimental evolution’ with soils
Provides solutions to local (Lincolnshire and East coast) and global challenges
