Fertilizer Potential of Sea Weed (Kappaphycus and Gracilaria) Saps in Potato Crop

Potato (Solanum tuberosum Linn.) is one of the most important crops in Bihar after rice, wheatand maize. It is well known fact that potato crop is a heavy feeder of nutrients. However,sole dependence on chemical fertilizers to meet its nutrient demandmay pose a great threat to sustainability of its production as the dosage of fertilizer used per unit area tends to increase year after year to obtain the same yield. This condition certainly not only increases cost of cultivation, but also resulted in decline in factor productivity and deterioration of soil health vis-à-vis soil fertility and causes environmentalpollution (Kumar et al., 2008). The ever increasing production cost of chemical fertilizers are also stressing to search for sustainable and eco-friendly alternative which can maintain high yield yet preserve ecological balance. Integrated plant nutrient supply is an important and promising component for sustainable productivity of crops and restores soil fertility (Kharub et al., 2003). In this context low input sustainable agriculture and reduced chemical input concepts with focus on green manuring, recycling crop residues inclusion of legumes in rotation and use of bio- fertilizers or other cheaper organic sources of nutrients to substitute a part of nutrient requirement are important, to make potato production an economically viable proposition.Integrated use of organic and inorganic fertilizers in potato based cropping system improves the soil health and productivity of the system (Singh and Lal, 2011). Seaweeds have been recognized as potential bio-fertilizer (Zhang and Ervin, 2008) and bio stimulant for improving growth and yield of many crops worldwide as it contains all the trace elements and plant growth regulators such as auxins, gibberellins and cytokinins in varying amounts. The information on the role of seaweed as a source of nutrients and as a growth promoting substance has also been established by Datta et al., (2003), Saravanan et al., (2003) and Shankar et al., (2001).