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Broccoli/Lettuce Intercropping in California, USA
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| Overview | Mixing broccoli and lettuce in an intercrop creates complementary patterns of resource use. |
| Scale | field, patch, local region |
| Location | Santa Cruz, California, USA (36.6N, 122.0W) |
| Elevation | 0 to 150 meters |
| Climate | Mediterranean or Dry Summer Subtropical (Cs) |
| Agricultural Region | Mediterranean Agriculture - (H) |
| Population Density | >35 persons / square kilometer |
| Principle Crops | Broccoli (Brassica rapa cv Premium crop), Lettuce (Lactuca sativa cv Deep red) |
| Domestic Animals | none |
| Soils | Mountain Soils, ustic great groups of Alfisols, Entisols, Inceptisols, Mollisols and Ultisols |
| Natural Vegetation | Needleleaf evergreen trees (E), Douglas fir- Redwood (29) |
| Ecoregion | Mediterranean Province (H11) |
| Basic Principles addressed | Conserve resources, Manage Ecological Relationships, Diversify, Empower People |
| Page Author and Date | Chris Bley from studies by Steve Gliessman |
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The yields of broccoli and lettuce grown together at three different planting densities were compared with yields from their conventional monocrops. Results demonstrate that broccoli/lettuce intercropping results in higher yields than can be produced by monocultures of lettuce and broccoli grown on the same area of land, a process known as overyielding. All three intercrop densities produced higher total yields than the combined monocrops, ranging between 10% and 36% greater yield. Lettuce heads in the intercrop were of slightly lower mean weight, but the combined production still exceeded the total that was produced by a combination of monocrops on the same amount of land. |
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Successful intercropping systems produce higher yields than is possible from monocrops on the same area of land (overyielding). Overyielding is attained when species' life histories and niches have complementarily resource use patterns, minimizing competitive interferences between crop species. Lettuce and broccoli have differing resource use patterns, because lettuce matures rapidly (within 45 days of being transplanted) and has a shallow root system, while broccoli has deeper roots and much slower growth. Broccoli and lettuce competition is minimal, because lettuce receives all the resources it needs to complete its growth before rapid broccoli growth begins. After lettuce harvest, broccoli takes full advantage of all available resources to complete its growth. Broccoli/Lettuce intercropping is therefore an ecologically successful intercropping system. Though intercropping can produce yield benefits, the economic and labor issues involved in large-scale intercropping, such as the sequential harvest of dense plantings, remain to be solved in California. |
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Conserve Resources Broccoli/lettuce intercropping conserves land and water resources over conventional monocropping systems. Manage Ecological Relationships By intensive intercropping of lettuce and broccoli, plants with complementary growth patterns in time and space, weeds can be managed and tillage reduced. Diversify Increased biodiversity is achieved by intercropping. |
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A Broccoli/Lettuce Intercrop Experiment at UC Santa Cruz
Aoki, M., A. Gilbert, A. Hull, M. Karlberg, and M. MacDonald. 1989. Multi-variable ecological analysis in a broccoli-lettuce intercrop. Unpublished data compiled for Environmental Studies 130. University of California, Santa Cruz.
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