C.C. HEMANTH*, M. MADHAN MOHAN, K.V. NAGA MADHURI AND P. MAHESHWARA REDDY

Department of Soil Science and Agricultural Chemistry, S.V. Agricultural College, ANGRAU, Tirupati.

ABSTRACT

An experiment on long-term application of fertilizers and manure was initiated in the year 1981 during kharif season

at Regional Agricultural Research Station, Tirupati, Andhra Pradesh, India in rainfed Alfisols under groundnut monocropping system. The same experiment was used for the present investigation during kharif, 2021 season, to study the influence of long-term application of fertilizers and manure on soil aggregate and aggregate associated carbon. The experiment has eleven treatments each replicated four times in a randomized block design. The results revealed that the soil aggregate fractions under long-term application of FYM @ 5 t ha-1 (T₂) and treatmental combinations viz., NPK+gypsum+ZnSO₄ (T₁₁), NPK + lime (T₁₀), NPK + gypsum (T₉) and NPK (T₈) recorded significantly higher in large and small macro-aggregates fractions compared to control and single nutrient fertilizers, which recorded highest in micro-aggregates fractions. The aggregate associated-C recorded significantly higher in large macro-aggregates compared to small macro and micro-aggregate fractions in both the soil layers. However, the aggregate associated-C was higher in surface layer compared to sub-surface layer.

KEYWORDS: Aggregates, Alfisols, long-term, treatment combinations.