Akhmad Mustafa, Muhammad Chaidir Undu and Kamariah
Soil quality plays pivotal role in increasing productivity and brackish water ponds successfulness, including ponds of Java Island, Indonesia. However, the availability of data on concentration categories for soil quality variables for ponds soils in Java Island, which is volcanic-dominated soils and the largest area for ponds in Indonesia, is still scarce. This study was aimed to categories soil quality variable concentrations as an initial point in interpreting pond soils quality of Java Island. Soil samples were collected from two different soil depths of 923 sampling points representing 13 regencies/cities of West Java, Central Java, and East Java Provinces. Twenty soil quality variables were measured based on in-situ and ex-situ measurements. The t-Student and U-Mann Whitney tests were applied to analyses the differences in soils quality at each soil depth which were firstly analyzed using z-score to eliminate outlier data. The data were firstly rearranged from the smallest to the largest data prior to measuring data deciles; the deciles, as considered as the basic measurement, were used for categorizing each soil quality variable. The results of this study indicated that the pH and nutrients are higher at pond top soils, 0-0.2 m compared to that observed on the depth of 0.2-0.5 m. Concentration of soil quality variables such as SKCl, SP, SPOS, TPA, TAA, TSA, and pyrite relatively similar between the two depths. Data of each soil quality variable were categorized into very low, low, moderate, high, and very high to facilitate a comparison to other data of ponds soil qualities. The results of this study are not recommended for assessing the relationship between ponds soil quality and ponds productivity; yet are usefull in measuring which variable of ponds soil quality is categorized as very low, low, moderate, high or very high; and also useful in making decision on pond soils quality management in Java Island.
