Effect of seaweed extract on growth and yield of onion

A field experiment was conducted during the Rabi season of 2009 to study the effects of soil applications of different concentrations of seaweed extract (prepared from Ascophyllum nodosum) on growth, yield and downy mildew severity of onion. The seaweed granules were applied as the basal dose (1.5, 2.0, 2.5, 3.0 and 3.5 g/m²). The soil application of seaweed extract significantly enhanced plant growth and yield. The highest yield was recorded with application of 2.5g/m² followed by 3.0g/m² that resulted in 120.8 per cent and 102.5 per cent increases respectively compared to control. The maximum increase in shoot height and number of shoots per plant and lowest disease severity were achieved with 2.5 g/m² seaweed extract application. Thus under sub–tropical, low hill conditions of Himachal Pradesh, soil application of seaweed extract could be a promising option for yield enhancement in onion.