Case Study: Algae in Agriculture

Algae in Rice Crops

Algae, or slime, is a perpetual problem in rice crops in Australia and in other parts of the world. In some years, it is so prevalent in the water, that large slabs of algae cover the surface, smothering the emerging rice crop.

Algae thrives where they are plenty of nutrients in the water and when plentiful sunlight encourages photosynthesis. The usual rice crop conditions of shallow water, fertiliser and sunlight create an ideal environment for the growth of algae.

Coptrol has adaptable application methods in the prevention and control of free-floating and filamentous algae in rice.

Far from being irritant and invasive, it is extremely adaptable in application. It can:

During wet seasons, the conditions for algae growth are also enhanced, as the water from rivers, creeks and reservoirs used on the rice crops contain a higher level of background nutrients.

Algae is commonly present in irrigation water and generally the rate they multiply is balanced by natural degeneration. However, when the balance is upset through increased energy from sunlight or extra nutrients, the rate of growth increases and the algae blooms become a problem in rice crops.

What are the effects of algae?

Inhibition of seedling germination and vigour

Plant pathologists suggest the possible effect of algae could be greater than that of fungi on germination during early growth of rice seedlings.

Uprooted seedlings

Respiratory and photosynthetic gases become trapped in the filaments tangled around seedlings, uprooting many seedlings which are not yet securely anchored.

Competition for nutrients

Slime lives and grows on the same nutrients as rice seedlings. In a blooming population, the sheer numbers of algal cells are enormous and represent a severe drain on the available nutrients.

Seedling knockdown and smother

When filaments of algae are in huge numbers, they smother and drown the emerged seedlings and a tremendous amount of damage has already been done. Remedial treatments will salvage the crop, but it is obviously better to avoid this damage before it happens. A good seedling stand is essential for high yields.

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