Abstract:
Usage of organic fertilizers is the best solution to overcome the detrimental effects
caused by synthetic fertilizers. However, readily available quality organic fertilizers
are limited. Microalgae could be used as bio fertilizers to the crops. A pot
experiment (1kg soil/ pot) was conducted to assess the potential use of Chlorella sp.
grown in wastewater on growth and yield of Ipomea aquatica with different organic
fertilizer and application combinations. Treatments were T1 Control (No fertilizer
application), T2 Chlorella soil application (SA) – 2 g/pot soil, T3 Chlorella SA – 4
g/pot soil, T4 Chlorella foliar application(FA) – 165 mg live biomass /pot through
foliar, T5 Chlorella FA- 33 mg dry biomass/pot through foliar, T6 100% cattle
manure 3.23 g/pot, T7 Chlorella SA- 1 g/pot soil + 50% cattle manure, T8 Chlorella
SA 2 g/pot soil + 50% cattle manure, T9 Chlorella FA 82.5 mg live biomass/pot
through foliar + 50% cattle manure, T10 Chlorella FA 16.5 mg dry biomass/pot
through foliar + 50% cattle manure, T11 50% cattle manure (1.61 g/pot).
Treatments were arranged as completely randomized design with three replicates.
Plant height, number of leaves, leaf area, and fresh and dry weight of edible yield
were measured at the end of four weeks. Data were statistically analysed using
ANOVA and mean separation was done using Duncan’s multiple range test. Results
of nutrient analysis of Chlorella indicated that it has considerable amount potassium
(0.73%), phosphorous (3.23%), nitrogen (27%) and carbon (38.05%). At the time
of harvest, significantly higher plant height was recorded in T2, T7 and T8,
significantly higher leaf number was observed in T3, while the significantly highest
leaf area was found in T3 compared with other treatments. The fresh and dry weight
yield were significantly higher in T2, T3, T7 and T8, and T2, T3 and T7 respectively,
indicating a better response to soil application of Chlorella compared to foliar
application. It is interesting to note that the yield of Ipomea aquatica was either
equal or higher in treatments of Chlorella as sole soil application or combination
with cattle manure compared to 100% cattle manure treatment, indicating the
potential of Chlorella sp. as a bio fertilizer.
