Field scale method

Field scale method: Demarcate the area in the field for algal production: - The suggested area is 40m². No special preparation is necessary although algal production is envisaged immediately after crop harvest, the stubble is to be removed and if the soil is loamy it should be well puddled to facilitate water logging conditions.

Prepare a bund with earth so as to store the water.
Flood the area with water to a depth of 2.5 cm.
In trough or pit methods flooding is done only in the beginning, while in field scale method flooding is repeatedly needed to keep the water standing.
Then apply superphosphate 12 kg/40 m².
To control the insect-pests attach, apply carbofuran (3% granules) or Furadon 250 g/ 40 m².
If the field has received previously algal application for at least two consecutive cropping seasons no fresh algal application is required. Otherwise apply the composite algal culture of 5 kg/40 m².
In clayey soils, good growth of algae takes place in about two weeks in clear, sunny weather, while in loamy soils it takes 3-4 weeks.
Once the algae have grown and formed floating mats they are allowed to dry in the sun in the field and the dried algal flake, are then collected in sunny bags for further use.
One can continually harvest algal growth from the same area by reflooding the plot and applying superphosphate and pesticides. In such situations an addition of algal inoculum for subsequent production is not necessary.
During summer months (April-June), the average yield of algae per harvest ranges from 16-30 kg/40 m².