Influence of organic and inorganic fertilizers on dynamics of nitrogen, phosphorus and potassium in relation to yield and proximate composition of Colocasia

Abstract

Field experiments were conducted during 2018-2020 to study the effect of integrated use of inorganicfertilizers and organic manure on the dynamics of nitrogen, phosphorus and potassium in relation to yieldand proximate composition of colocasia (Colocasia esculenta L) in an Alfisol. The inorganic fractions andavailable nutrient contents of N, P and K were found highest due to integrated application of FYM and½ NPK followed by application of 80-30-80 kg ha-1 of N, P and K. Sequence of occurrence of inorganicP fractions (mg kg-1) in the soils followed the order: Reductant soluble P (42.39) > Fe-P (38.10) >Ca-P (30.23) > Al-P (23.71) > Bray’s-1-P (17.86) > Water soluble P (2.94). Occurrence of differentK fractions (kg ha-1) was in the order: NH4OAc-K (210.05) > exchangeable-K (186.56) > nonexchangeableK (111.54) > water soluble-K (23.49). Available N was contributed mostly by NO3-N andtotal N. All the inorganic P fractions contributed significantly to the available P pool and the relationship(r) was found to be in the order of water soluble P (0.97**) > Fe-P (0.96**) > RS-P (0.95**) > Al-P(0.94**) > Ca-P (0.90**). However, exchangeable K and total K contributed significantly towards theavailable K content of the soil. Ammoniacal N showed a highly positive and significant relationship withcorm yield and biochemical constituents of taro. Iron bound P and Al-P fractions contributed mostlytowards the P nutrition of colocasia. Of all the K fractions, non- exchangeable K has recorded higher ‘r’values with cormel yield and bio-chemical constituents. Application of organic manure and half of thesoil test based NPK not only sustain the soil quality and enhanced the productivity of colocasia but alsohad greater impact on NPK transformations in Alfisols.