Agroecology and Conventional Agriculture Concepts

Vocabulary flashcards covering conventional agricultural practices, agroecological management strategies, water and wind dynamics, and systems research concepts from the lecture notes.

Intensive Tillage

Loosens soil initially, but destroys organic matter, degrades soil structure, and accelerates wind and water erosion over time.

Monocultures

Maximizes machinery efficiency, but drastically reduces agrobiodiversity and leaves crops highly vulnerable to widespread pest infestations and diseases.

Synthetic Fertilizers

Provides quick N, P, and K for high yields, but leaches into waterways (causing eutrophication) and emits greenhouse gases during industrial production.

Irrigation Overuse

Consumes $70\%$ of global water use, leading to aquifer overdrafting, river diversion, and soil salinization.

Chemical Pest Control

Drives the "pesticide treadmill" by eliminating natural predators and selecting for pesticide-resistant pest populations.

Genetic Homogeneity

Heavy reliance on uniform hybrid or GE crops (e.g., glyphosate-tolerant, Bt) accelerates superweed development and locks farmers into chemical dependence.

CAFOs (Concentrated Animal Feeding Operations)

Separates livestock from crops, turning animal manure from a valuable natural soil amendment into a major point-source of air and water pollution.

Excess Water Management (Agroecological)

Uses raised field platforms and canals (camellones and zanjas), integrates wetland-adapted crops, and builds soil organic matter to improve natural drainage.

Water Scarcity Management (Agroecological)

Relies on rainwater harvesting, organic mulches to restrict evaporation, fallow rest periods to recharge soil moisture, and deep-rooted or drought-tolerant cultivars.

Wind Impacts (Negative)

Strips the boundary layer of moist air around stomata (accelerating desiccation/wilting), causes crop lodging (flattening), accelerates topsoil erosion, and spreads pests/diseases.

Wind Impacts (Positive)

Facilitates pollination in wind-pollinated species, increases canopy air circulation to mitigate fungal pathogens, and helps regulate $\text{CO}_2$ exchange for photosynthesis.

Agroecological Wind Mitigation

Plants porous tree/crop windbreaks to reduce velocity, hills soil around roots, plants deeper, and breeds crops for stalk strength and shorter stature.

Boundary Layer

A thin layer of still, moist air surrounding plant leaf stomata. Wind removes this layer, increasing transpiration and risking plant desiccation.

Camellones and Zanjas

Traditional raised field platforms (camellones) and surrounding drainage/irrigation canals (zanjas) used in agroecology to manage excess water.

Environmental Complex & Safe Sites

Plant growth depends on a matrix of abiotic/biotic factors. Seeds require "safe sites"—microenvironments providing exact conditions for germination while remaining free of toxins, predators, and pathogens.

Spatial Heterogeneity

Natural landscapes are inherently varied. While conventional farming uses brute force (tillage, chemicals) to impose artificial uniformity, agroecology designs farming practices around natural landscape variation.

Reductionist Science

Research that isolates single variables in short-term, small-scale factorial trials (e.g., $\text{Yield} = f(\text{fertilizer})$), assuming system components combine linearly and ignoring real-farm complexity.

Systems Research & Emergent Properties Premise

Operates under the principle that the whole agroecosystem is greater than the sum of its individual parts, evaluating feedback loops, non-linear interactions, and long-term ecological shifts.

The 3 Shifts in Systems Research

1. Rethink (ask holistic questions about system interactions), 2. Redesign (use flexible, system-level experiments), 3. Regroup (build interdisciplinary teams with farmers).

Symbiosis: Mutualism vs. Commensalism

Mutualism is an interdependent interaction where both species benefit (e.g., Yucca plant and Yucca moth). Commensalism is where one species benefits without harming or benefiting the other.

Biological Nitrogen Fixation

A mutualistic interaction where legumes (e.g., clover, vetch, field beans) host Rhizobium bacteria in root nodules to convert atmospheric $\text{N}_2$ into plant-available soil nitrogen.

Allelopathy

The biological phenomenon where a plant releases biochemical compounds that actively inhibit or stimulate the growth, germination, or development of neighboring organisms (e.g., squash suppressing weeds).

Multi-Functional Roles of Cover Crops

Cover crops (e.g., crimson clover, hairy vetch) fix atmospheric N, suppress weeds via shade and allelopathy, build soil organic matter, prevent erosion, and provide habitat for beneficial insects.

Conventional vs. Agroecological Pest Control

Conventional uses synthetic pesticides (causing the pesticide treadmill); agroecology uses biological control, allelopathy, polycultures, and natural habitat enhancement.

Conventional vs. Agroecological Soil Fertility

Conventional relies on synthetic N/P fertilizers (causing water pollution and greenhouse gas emissions); agroecology builds fertility using legume N-fixers, cover crops, and integrated animal manure.