BIOL 313 Ch 4 Agricultural Systems Notes

Overview

  • Agricultural system type depends on crops, soil, climate, topography, and socioeconomic factors.

Agricultural Systems

  • Best land for profitable plant crops; livestock on dry, rough, elevated land or far from market.

  • Midwest shifted to corn due to improved market access.

Rainfall Influence

  • <20\ \text{inches} (semiarid to arid): primitive agric., nomadic/herding.

  • 20\ \text{to}\ 30 (subhumid): shifting cultivation, rudimentary sedentary tillage; subsistence.

  • >30\ \text{inches} (humid): developed agric., ranching, grain, commercial livestock/crop farming.

Nomadism

  • Move based on food; subsistence herding in deserts, savannahs, cold areas; no land ownership; sustainable arid land use; vulnerable to drought/war.

Transhumance

  • Permanent settlement with seasonal livestock movement; common in mountains (summer in mts, winter in valleys).

Shifting Cultivation

  • Clear plot, farm for years until fertility declines, abandon for new plot; "slash-and-burn" provides nutrients; subsistence; in remote tropics; 10–20 year cycles; converting to sedentary tillage.

Rudimentary Sedentary Tillage

  • Sedentary but uses shifting cultivation techniques; primitive; repeated planting reduces soil fertility; keeps some animals.

Paddy Rice Farming

  • Rice grown with available water; labor-intensive; uses draft animals; pigs/poultry in fields; sustainable subsistence system; can include fish.

Peasant Grain & Livestock

  • Small, self-sufficient farms; mostly subsistence, small surplus; few multipurpose livestock; mostly grains, some cash crops; widespread.

Ranching

  • Commercial use of dry areas (<20\ \text{inches} rain); livestock (cattle/sheep); extensive mgmt; one species; owned/leased land; profit-driven; may include forage farming.

Commercial Livestock Finishing

  • Began ~50 years ago; US largest; High Plains concentrated; highly specialized; vertically integrated; swine/poultry common globally.

Commercial Dairy Farming

  • Milk near population centers; other dairy products farther; historically pasture-based, now more confinement/dry-lot; large-scale.

Commercial Grain Farming

  • Rainfall >20\ \text{inches}; some livestock; focus on grains (corn, rice, wheat).

Mediterranean Agriculture

  • Historically peasant subsistence (wheat/barley in winter, vines in summer); mountain grazing; irrigation shifted to citrus, grapes, market gardening.

Market Gardening

  • Produces for large urban areas; no livestock; focus on fruits, vegetables, flowers; labor-intensive, seasonal workers.

Urban Agriculture

  • In cities; mostly subsistence for urban dwellers; fruits, vegetables, herbs, bees, chickens, fish, pigs; sustainable practices (gardens, rooftops, hydroponics).

Commercial Plantations

  • Large landholdings; labor-intensive; single cash crop; tropical developing regions; owned by government/corporations; few animals; some mechanization.

Aquaculture

  • Historically subsistence, now growing commercially; half world’s seafood; sustainable fish source; can integrate with hydroponics.

Organic Farming

  • No synthetic pesticides, fertilizers, GMOs; growing globally; yields ~20% lower than conventional; requires more land.

Developed vs Subsistence

  • Subsistence: inefficient but sustainable; low capital; draft power; grow fuel; provides jobs.

  • Developed: higher startup costs (machinery, chemicals) but higher productivity/profit.

Developing Livestock

  • Developing countries: small farms, family labor, low productivity; Developed: massive operations, or small hobby units.