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close this bookAmazonia: Resiliency and Dynamism of the Land and Its People (UNU, 1995, 253 pages)
close this folder6. Agro-forestry and perennial cropping systems
View the document(introduction...)
View the documentDiversity in space
View the documentDiversity in time
View the documentAgro-forestry integration with aquaculture and livestock
View the documentLaissez-faire biocontrol
View the documentInnovation at Tomé-Açu
View the documentRevival in the Bragantina zone
View the documentThe pioneer experience: Transamazon and Rondônia
View the documentThe emergence of nurseries for perennial crops
View the documentComparisons with the Old World tropics
View the documentCash crops on the horizon
View the documentConstraints on further intensification

Laissez-faire biocontrol

Few farmers routinely use pesticides on their perennial crops in the Amazon, and then only sparingly. Vegetable growers, particularly near the major cities, use the most pesticides. The high cost of pesticides is a major constraint to their use. Experience is showing, however, that growing perennials in discrete patches or in mixed cropping systems often reduces the need for pesticides. Also, patches of forest and old second growth may allow biocontrol agents to thrive, as appears to be the case with oil-palm plantations along the PA 150 road in Pará, Much research remains to be done, however, to understand the interaction of crops and pest populations, and the role of vegetation in suppressing or encouraging pests.

The owner of the Rio Branco ranch near Ariquemes, Rondônia, notes that orange trees appear more vigorous near a strip of exotic bamboo he has planted along the road dividing his property. The bamboo was originally planted for ornamental purposes, but the rancher plans to plant more near his orange plantings. Bamboo's effects on the orange orchards are unclear; the perennial grass may be benefiting the orange trees by providing a haven for predators of insect pests, or it may be serving as a windbreak. Elsewhere in pioneer areas of Amazonia, bamboo is planted as a door yard plant for construction material; Japanese-Brazilians also harvest bamboo shoots for a variety of dishes.