Ulvaceae

Visually, these organisms resemble bright green mats or sludge that can densely cover the water surface or substrate. Their tissues are very fragile, easily broken by mechanical disturbance, and have a characteristic intense grass-green color.

The cellular structure of Ulvophyceae features chloroplasts, which enable intense photosynthesis. The primary method of reproduction is spore formation, where the algae release thousands of zoospores into the water, rapidly colonizing new areas.

In field conditions, these algae are often confused with other filamentous species. However, unlike others, Ulvophyceae have a specific life cycle with an alternation of generations, making them extremely resilient to external environmental factors.

Accurate identification often requires microscopic analysis, as macroscopically they can appear as a uniform green mass filling irrigation canals or rice paddies.

Ulvophyceae primarily inhabit aquatic environments, including stagnant and slow-moving bodies of water. In agriculture, their main locations include irrigation systems, canals, and flooded rice fields.

They prefer waters rich in nitrogen and phosphorus, which is often linked to the active use of mineral fertilizers. An excess of nutrients in the water triggers rapid blooming and swift coverage of large areas.

The algae can withstand temporary fluctuations in water levels, surviving in damp soil as spores or resting stages until the next flooding cycle. This makes them constant inhabitants of rice crop rotations.

Ulvophyceae spread mainly via irrigation water currents that carry their reproductive parts to new zones. Furthermore, birds and agricultural machinery can act as vectors for spore dispersal over long distances.

In warm climates with high solar activity, Ulvophyceae form massive clumps that can completely block the water surface, disrupting the normal hydrological regime of the irrigation system.

The harmfulness of Ulvophyceae lies in the creation of a dense "carpet" on the water surface, which sharply limits the penetration of sunlight to crop plants, particularly rice during early growth stages.

Massive algae clusters absorb significant amounts of mineral elements from the water, competing with crops for nutrients. This leads to stunted growth and a reduction in potential crop yields.

During the decay of dead Ulvophyceae mass in the rice root zone, large amounts of oxygen are consumed. This triggers anaerobic processes in the soil, promoting root rot and the release of gases toxic to rice.

The proliferation of these algae physically hinders agronomic practices, including crop maintenance and the management of water levels in fields. They clog water intake units and filtration systems.

The constant presence of dense algal masses facilitates the multiplication of harmful insects and pathogens that find shelter and an additional moisture source in them, creating a favorable microclimate for diseases.

The primary agronomic method for control is thorough field preparation and adherence to proper flooding regimes. It is important to prevent water stagnation and ensure circulation, which slows the growth of green algae.

An effective control method is the timely cleaning of irrigation canals from plant residues and bottom sediments where Ulvophyceae spores may persist. This reduces the primary algal population before the season starts.

Chemical control includes the use of specific algicides based on copper or other compounds authorized for regional use. It is crucial to strictly adhere to dosages to avoid negative impacts on the main crop.

Fertilizer application must be strictly measured, as excessive nitrogen input directly provokes spikes in Ulvophyceae populations. Optimizing mineral nutrition allows for reduced pressure on the ecosystem of the field.

• Mechanical removal of algae mass using rakes for smaller volumes.
• Use of biological agents that promote natural inhibition of algae growth.
• Timely water drainage to dry the surface and dehydrate the algae.