Earthworm Pontoscolexcorethrurus and Nitrogen Mineralization Rate in Incubation Experiment with Different Quality Organic Matters from Sugaragro-Industry Waste.

ABSTRACT

To investigate the effect of earthworm inoculation on N mineralization rates of different quality organic matters from sugar agro-industry waste, we conducted a green house incubation experiment for 14 weeks in pots containing 7 kg dry soil. There are 12 treatment combinations.Factor I waswith (P) and without inoculation of P.corethrurus (N). Factor II was the type of OM which consisted of six levels (1) without application of OM (control), (2) cow manure (CM), (3) filter cake (FC), (4) sugarcane trash (ST), (5) a mixture of CM + FC and (6) a mixture of CM + ST. The treatments were arranged in a factorial randomized block design with three replications. The amount of released N-NH4 +and N-NO3 - or mineral N was measured during incubation time from 1, 2, 4, 8, and 14 weeks after inoculation of earthworms. There was a significant effect of earthworm inoculation on N mineralization rate of different quality organic matters. Overall, rate of net N mineralization were higher in treatments with earthworm inoculation than without earthworm inoculation and the magnitude of the increase appears to dependent on the quality of organic matters. The largest difference were seen on ST and CM+ST treatments with the increase by 90 % and 157 % and the constant of N mineralization rate by 0.0147 and 0.0180 week-1 for the treatment with earthwormsinoculation.These results suggested that application of sugar agro-industry waste although having low quality can improve soil N availability in sugarcane land when aided by P.corethrurus activity.