Soil fertility status in tidal land of Tirtomarto reservoir, Central Java, Indonesia

Reservoir tidal land used for agriculture is generally done when the reservoir water level begins to shrink. This land is used as a moor in dryland or lowland rice fields in the wetland. The purpose of the study was to determine the soil fertility status of the tidal land of the Tirtomarto reservoir, Central Java. Parameters tested include cation exchange capacity (CEC); base saturation (BS); C-Organic; total soil P and K levels according to the technical instructions for evaluating soil fertility. Soil samples were taken from three location points by the purposive sampling method. The results showed that most of the soil samples contained low to very low nutrients, except for the total P content which had a high value. Therefore, the fertility status in the tidal land of the Tirtomarto reservoir, Central Java, can be categorized as low. The low fertility status of the soil at the study site was due to the limiting factors, namely the low C-organic content of the soil, low K total soil, and low cation exchange capacity and base saturation.