PJB-2022-373
A combined application of humic acid and farmyard manure revamp soil fertility and microbial activity under alkaline condition
Shahzad Afzal
Abstract
Humic acid (HA) improves soil solids surface chemistry and thereby optimizes biological activity and fertility of soil. However, its interactive effect with farmyard manure (FYM) under calcareous soil is not fully explored. Therefore, laboratory incubation experiment (1st) was conducted to investigate effect of various levels of lignitic coal derived humic acid (0, 100 and 200 mg kg-1 soil) applied alone or in conjunction with 10 g FYM kg-1 on soil fertility and microbial activity for 79 days. In other experiment (2nd), the same soil was remoistened and treated with lower levels of HA (0, 2, 4, 6, 8 and 10 mg kg-1) for 14 d for further verifying its effect on soil microbial activity. The combine application of humic acid and FYM significantly increased CO2 release except at 2nd d, however, application of 100 and 200 mg HA produced non-consistent supremacy over each other at different incubation intervals. Conjunctive use of HA and FYM consistently accelerated the rate of CO2 production over all incubation intervals as compared to sole application of HA or control. Cumulative release of CO2 also showed that application of HA either as 100 or 200 mg produced higher (1014 and 1035 mg CO2 kg-1), respectively as compared to 918 mg kg-1 of control at the end of 79th day. Integrated use of HA+FYM amplified cumulative CO2 releases as compared to control or alone HA at both levels. In the second experiment, application of HA consistently increased CO2 release with increasing doses up to 6 mg HA kg-1 at all incubation intervals. So the conjunctive use of HA with FYM further accelerated the good results of HA on soil and the lower dose of 6.0 mg kg-1 seemed to be the appropriate dose.
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