Renán Agüero

Diversity and Spatial Heterogeneity of Weed Communities in a Sugarcane Cropping System in the Dry Tropics of Costa Rica

Weed diversity, structure, and distribution within and outside agricultural fields affect not only ecological processes but also weed management strategies. We studied how areas managed differently within and outside the field determine weed communities in a sugarcane cropping system in the dry tropics of Costa Rica. A total of 120 weed species were detected, which was similar to surveys conducted in subtropical and temperate conditions. Weed species richness was highest in undisturbed field borders and lowest in rows and furrows. The area where tractors turn within the field (turn area) had similar richness compared with the borders, despite being one of the most disturbed management areas studied. The most predominant weed species were divided between generalists and species that exhibited clear preferences for management area or soil texture. Soil texture was more important for determining weed community structure than management area when considering weed species affecting weed control decisions. The results indicated that disturbance in the management area and, especially, weed control practices are critical factors affecting weed diversity, but availability of resources for weed growth such as nutrients, soil moisture, and light can mitigate some of the limitations imposed by weed control on weed diversity, especially in the turn area. Differences in weed communities between management areas within fields indicated the existence of conditions that favor key weed species, and this information can be used to anticipate their population growth and help determine when and where more intensive control should be implemented. Nomenclature: sugarcane, Saccharum officinarum L.

Automation for Weed Control in Least Developed Countries (LDCs)

The state of the art in automation for weed control makes it foreseeable that the rate of adoption of these technologies will increase significantly in developed countries within the next decade, as specific applications that are effective and affordable become available. For least developed countries (LDCs), international cooperation must be sought in order to avoid a steep increase in the technology divide. Furthermore, automated weed control could play a significant role in supporting the adoption of weed control strategies that are less damaging to the environment while helping improve food supplies for LDCs. However, since the agricultural systems are rather diverse in these countries, several aid programs will be needed. As these programs develop, stories of success by early adopters could play an important role in promoting widespread use of these technologies among LDCs.