Vol. 11, Issue 5 (2022)

Author(s):
Chetana Banasode and Channakeshava S

Abstract:
A field experiment was conducted during Kharif and Rabi season of 2019-20 in paddy - cowpea cropping system at Bhairapura village, Hassan district, Karnataka to study the effect of zinc and boron application on fractions of zinc and boron in soil of paddy-cowpea cropping sequence. Paddy was the test crop to study the direct effect and cowpea crop was raised to study the residual effect. The experiments were laid out in Randomized Complete Block Design with thirteen treatments and replicated thrice. At harvest of paddy and cowpea crops, T₇ treatment (NPK + FYM + 25 kg ha^-1 ZnSO₄+ 10 kg ha^-1 Borax) recorded significantly higher water soluble and exchangeable, organically complexed, amorphous and crystalline sesquioxide bound, manganese oxide bound and residual zinc and it was at par with T₅ (NPK + FYM + ZnSO₄ @ 25 kg ha^-1 + Borax @ 5 kg ha^-1). Among the fraction, the residual zinc recorded highest zinc fraction and water soluble zinc recorded lowest zinc fraction. Significantly higher readily soluble, specifically adsorbed, oxide bound, organic matter bound, residual and total boron was observed in T₇ treatment (NPK + FYM + 25 kg ha^-1 ZnSO₄+ 10 kg ha^-1 Borax) compared to other treatments at harvest of both crops. Residual boron has highest contribution to total boron as compared to other fractions.