Carbon Organic Content under Organic and Conventional Paddy Field and its Effect on Biological Activities (A Case Study in Pati Regency, Indonesia)

Abstract

The low organic matter content of paddy soils impacts the declining quality of land. Without the efforts to enrich the soil organic matter (SOM) content, the productivity of paddy fields will decrease or the need for inorganic fertilizers will increase to reach the level of yield. The present research aims to determine the effect of differences in organic and conventional paddy fields management practices on soil organic carbon (SOC) content and biological activities. The research was conducted from July to September 2018 on organic and conventional paddy fields in Dukuhseti Sub-district, Pati Regency, Central Java, Indonesia. Sampling points were taken from six organic samples in the organic paddy fields while the other six samples were taken from conventional paddy fields. The variables observed in this research were organic C, pH, total N soil, total bacterial colonies, soil respiration and microbial biomass C. The results show that the organic C content in the organic paddy field (2.4%) was higher than that of the conventional paddy field (1.8%). The C content of organic paddy fields increased by 0.6%. The differences of the total bacterial colonies, soil respiration and microbial biomass C between organic paddy fields and conventional paddy fields were 11.5 CFU g<sup>-1</sup>, 7.42 mg CO<sub>2</sub> week<sup>-1</sup> and 0.51 µg g<sup>-1</sup>, respectively, because the use of organic farming systems could improve the biological nature of soils and caused biological activity in organic paddy fields to have the highest value compared to conventional paddy fields.