Weed Infestation Patterns and Problem Species in Sunflower Crops:
 A Case Study from NARDI Fundulea

Mihaela Cergan, Gheorghe Măturaru, Elena Partal, Florin Gabriel Anton 

National Agricultural Research and Development Institute Fundulea

Keywords: sunflower, weed density, degree of infestation, weed species, yields.

Abstract: In Romania, sunflowers crop belonging to the order Compositales (Asterales), family Compositae (Asteraceae), are heavily level of infestation with annual and perennial weed species. This high weed diversity intensifiescompetition for the development of the crop plant, negatively affecting plant growth, grain yield, and overall crop quality when appropriate control measures are not applied.
Given the distinct biological characteristics of these weeds compared to the crop plant, their behavior under the climatic conditions of Fundulea requires detailed study.
In the experimental field at NARDI Fundulea, the sunflower crop showed a high degree of infestation (65-85%) with characteristic species, depending on the location area, the applied technological links and the preceding crop. The cause of the appearance of different weed species is correlated with climatic factors, with the seed reserve in the soil and the limited competitive ability of sunflower plants.
The research focused on determining the weeds, identifying and predominance of the existing weed species in the untreated variants located on the cambic chernozem soil type (3.2% OM; 37 clay, Ph 6.5) of the experimental field.
The main objective of the work was to study the weed species and identify the “problem weeds” (Setaria viridis, Echinochloa crus - galli, Sorghum halepense, Xanthium strumarium, Ambrozia sp., Cirsium arvense) that cause significant annual production losses and increased management costs.The presence of annual and perennial weeds in sunflower crops throughout the vegetation period is a reality that causes various quantitative (by reducing the level of production) and qualitative (by decreasing the quality of crops) problems.