Vol. 8, Issue 11 (2019)

Author(s):
B Gowthami, P Guru Murthy, Ch. Sujani Rao and M Sree Rekha

Abstract:
A field experiment was conducted to study the soil quality impacted by addition of various rates of biochar in combination of recommended dose (100% RDF or 75% RDF) of chemical fertilizers to groundnut crop in red sandy loam soils of North Coastal Andhra Pradesh during rabi, 2018-19. The quality of initial soil before imposing various treatments viz., control (T₁), 100% RDF only (T₂), 100% RDF + biochar @ 2 t ha^-1 (T₃), 100% RDF + biochar @ 4 t ha^-1 (T₄), 100% RDF + biochar @ 6 t ha^-1 (T₅), 75% RDF + biochar @ 2 t ha^-1 (T₆), 75% RDF + biochar @ 4 t ha^-1 (T₇) and 75% RDF + biochar @ 6 t ha^-1 (T₈) was belong to class III with soil quality index of 290 and relative soil quality index of 72.5%. After completion of the experiment with groundnut crop, the SQI and RSQI values for T₁ (control) treatment @ 284 and 71% respectively. The highest SQI and RSQI values @ 352 and 88.0% were recorded in the treatment received biochar @ 6 t ha^-1 + 100% RDF (T₅) which was followed by T₄, T₈, T₃, T₇, T₆, T₂ and T₁. The soil under control (T₁) and 100% RDF alone (T₂) treatments was remain in same soil quality class III after completion of the experiment. Substantial improvement in some of the soil quality indicators like cation exchange capacity (CEC), organic carbon content, available N, P₂O₅ and K₂O, microbial biomass, soil respiration, activity of urease and phosphatase enzymes, which in turn shifted the soil quality category of T₃, T₄, T₅, T₆, T₇ and T₈ treatments from Class III to Class II at the end of experiment.