Amazon Basin Soils: Management for Continuous Crop Production

Abstract

Technology has been developed which permits continuous production of annual crops in some of the acid, infertile soils of the Amazon Basin. Studies in Yurimaguas, Peru, show that three grain crops can be produced annually with appropriate fertilizer inputs. Twenty-one crops have been harvested during the past 8(1/2) years in the same field, with an average annual production of 7.8 tons of grain per hectare. Soil properties are improving with continuous cultivation. The technology has been validated by local farmers, who normally practice shifting cultivation. Economic interpretations indicate large increases in annual family farm income and a high return on the investment of chemical inputs. Other promising land use alternatives include low-input crop production systems, paddy rice production in fertile alluvial soils, and pastures or agroforestry in rolling areas. Stable, continuous food crop production is an attractive alternative to shifting cultivation in humid tropical regions experiencing severe demographic pressures. For each hectare of land managed in a highly productive manner, there may be less need for clearing additional tropical forests to meet food demands.

In vitro susceptibility of Plasmodium falciparum Welch field isolates to infusions prepared from Artemisia annua L. cultivated in the Brazilian Amazon

“…Previous studies have reported that leaves of this hybrid have artemisinin levels in the range 0.8-1.2% (Magalhães et al 1997, Marchese et al 2001. No large variation in the levels of artemisinin among the hybrids in the three Amazonian ecosystems was observed despite the rather large differences in the nutritional composition of soils of the várzea, terra preta de índio and terra firme areas (Sanchez et al 1982). The levels of artemisinin found in these hybrids cultivated in the Amazon are similar to those found in the standardised and stabilised plants from Paulínia from which the Amazon hybrids are derived.…”

Dinâmica de íons em solo ácido lixiviado com extratos de resíduos de adubos verdes e soluções puras de ácidos orgânicos

“…Efeitos benéficos do manejo orgânico de solos ácidos têm sido observados em diversos sistemas agrícolas, cujas principais alterações químicas na camada de 0 a 20 cm de profundidade são: elevações do pH e do teor de Ca em detrimento do Al (Sanchez et al, 1982;Hue & Amien, 1989;Bessho & Bell, 1992). Em alguns casos, esses efeitos se estendem à subsuperfície do solo (Watt et al, 1991;Pavan, 1994;Liu & Hue, 1996;Oliveira & Pavan, 1996).…”

Fungos micorrízicos arbusculares em seringueira em latossolo amarelo distrófico da amazônia ocidental

“…Os principais fatores para que isso ocorra são: baixa fertilidade do solo, com elevada acidez e baixa soma de bases (SANCHEZ et al, 1982;MOREIRA e FAGERIA, 2009) brasiliensis), a presença do fungo Microcyclus uley (mal-das-folhas) reduz significativamente a produção de látex (GASPAROTTO et al, 1997).…”