Improvement of Physical and Biological Quality of Soil in a Sugarcane Plantation through the Management of Organic Matter Input

Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicator. This research aimed to study the effect of the addition of various quality and quantity of organic matter on soil biology (earthworms) and physical quality (aggregate stability, macroporosity and infiltration rate). There were 15 treatment combinations tested. The first factor is the type of organic matter: (1) cattle manure (CM), (2) filter cake (FC), (3) sugarcane trash (ST), (4) a mixture of CM + FC and (5) a mixture of CM + ST. The second factor is the application dose of organic matter, which consists of three levels—5, 10 and 15 Mg/ha. The treatments were arranged in a factorial randomized block design with three replicates and one control treatment (without organic matter input). The result of this research showed that the highest population density of earthworms was found in the treatment of ST (78 individuals/m 2 ) and a mixture of CM + ST (84 individuals/m 2 ). The type of organic matter with C/N ratio ranged from 15.5 to 34.7 and cellulose content in 33.3%-40.1% gave better growth of earthworm. The effect of increase in earthworm growth on soil physical improvement is more apparent in the treatment of mixture of low quality and high quality organic matter. The increase of earthworm density and biomass enhanced soil macroporosity (from r = 0.683 to r = 0.606) and infiltration rate (from r = 0.669 to r = 0.756). The results of this study suggest a mixture of CM + ST or ST alone as organic matters, which is recommended to improve soil physical and biological quality of sugarcane land, with the dose application ranged from 10 Mg/ha to 15 Mg/ha.