Dynamics of PH, Ferrum and Mangan, and Phosphorus on Newly Opened Paddy Soil Having High Soil Organic Matter on Rice Growth

Research had been carried out at the Research and Soil Testing Laboratory and Greenhouse of Soil Research Institute, Bogor using newly opened paddy soil from Pesisir Selatan districts, West Sumatra (one year old). Total treatments tested were 12 which were combination of farmer rate, NPK recommendation (½×; ¾×; 1½×), straw compost (½×; ¾×; 1½×), and dolomite. The trial was conducted using a completely randomized design with three replications. This research had been prepared in two units, one unit for observing plant response to nutrient management and another unit for incubation trial with the same treatment placed in the greenhouse.  Rice cultivar used was IR-42 in accordance to the preferred varieties of local farmers. The sampling method for measuring the solubility of Fe2+ and Mn2+, as well as the availability of PO43- was by centrifuge 50 g mud samples from the incubation pots then separated clear extract using filter paper. The observation results on dynamics of pH, Fe2+, Mn2+ and PO4-3 mainly occured in 1 to 14 days after submerging (incubation). After 14 days soil reaction had reached thermodynamic sequence of oxidation-reduction processes, the PO43- more available and pH of the soil reached the peak. The optimum dose of NPK fertilizer obtained 0.875 NPK or equal to 175 kg of urea, 87.5 kg of SP-36 and 87.5 kg KCl ha-1. The highest number of hills achieved from straw compost treatment 1½ organic matter (OM) or 3 tons with an increase of 20%. Application of ameliorant dolomite increased the number of tillers about 2-3%, but insignificantly different with no dolomite treatment.Keywords: Ferrum, mangan, paddy soil, phosphate,, rice, soil pH[How to Cite: Widowati LR and Sukristyonubowo. 2012. Dynamics of pH, Ferrum and Mangan, and Phosphorus on Newly Opened Paddy Soil having High Soil Organic Matter on Rice Growth. J Trop Soils 17 (1) : 1-8. doi: 10.5400/jts.2012.17.1.1] [Permalink/DOI: www.dx.doi.org/10.5400/jts.2012.17.1.1

Pengaruh Pupuk Majemuk NPKS Dan NPK Terhadap Pertumbuhan Dan Hasil Padi Sawah Pada Inceptisol

Rate of NPK fertilization on rice using NPK compound fertilizer needs to consider soil nutrient status and plant nutrient requirement. The research was aimed to determine the optimum rate of compound fertilizer and the effect of enriched S nutrient of NPKS compound (15-15-15-5S) and NPK compound fertilizer (15-15-15) on the growth and yield of rice. The experiments were conducted at two sites in Galuga, Ciampea Bogor, West Java from April to September 2013, using randomised complete block design with 3 replications. Experiment at site I consisted of 9 treatments: six levels of fertilizers NPKS i.e. 0; 150; 300; 450; 600; and 750 kg/ha, standard fertilizer, NPK compound fertilizer equivalent to standard, and standard fertilizer plus S. Rate of urea, SP-36, and KCl for standard fertilizer treatment was respectively 250, 75, and 50 kg/ha. At site II the treatments consisted of 6 levels of NPK compound fertilizer i.e. 0; 150; 300; 450; 600; and 750 kg/ha and the standard fertilizer with rate of 250 kg/ha of urea, 50 kg/ha SP-36, and 75 kg/ha KCl. Plot size was 4 m x 5 m planted with Ciherang variety. Data collection included chemical properties of soil before and after the experiment, plant height, number of tillers, straw weight, and dry grain weight and the nutrient uptake. The effectiveness of fertilizer was calculated by RAE (Relative Agronomic Effectiveness). Results showed that fertilizer NPKS (15-15-15-5S) at 600 kg/ha effectively increased dry grain weight from 3.63 t/ha to 4.67 t/ha, but was not significantly different from a standard fertilizer treatment. It increased dry grain weight by 29% compared to control. NPK fertilizer (15-15-15) effectively promoted growth and dry grain weight equivalent to standard fertilizer at rate of 300-750 kgha. The optimum rate of NPK compound fertilizer (15-15-15) was 440 kg/ha as was shown with the production performance of 4.12 t/ha with RAE by 58%. NPKS compound fertilizer with rate of 750 kg/ha showed the highest uptake of N, P, and K nutrients and significantly increased the available P in the soil. Whereas NPK compound fertilizer with a rate of 600 kg/ha indicated the highest P nutrient uptake. Fertilizer enrichment with sulfur on NPKS fertilizer (15-15-15-5S) did not significant affect on grain dry weight

Nitrogen Dynamics and Nitrate Leaching in Intensive Vegetable Rotations in Highlands of Central Java, Indonesia

High rainfall intensity is major factor governing leaching process, where leaching is often the most important process of N loss from the field and lead to agricultural environmental pollution. In order to measure the movement of mineral-N in soil profile, a field research had been conducted in two sites of center vegetable farming area with six farmer cooperators in Central Java, Indonesia. Regular soil sampling was done from Improve Practice (IP) and Farmer Practice (FP) treatment for three planting seasons during 2007. Almost all treatments FP applied higher rate of N fertilizer compare to IP, but it was not reflected in N profile.  Comparison of predicted and measured mineral N content was simulated using Burns α  model, then the closeness of the estimation and measured calculated using Coefficient of Residual Mass (CRM) calculation as an indicator with 0 as ideal value.  Out of 9 measurements of IP and FP treatment, eight and seven measurements had negative CRM  representinga slight overestimation. The NO3-N loss estimated using the Burns α model for IP and FP was in average of 67% for IP and  71% for FP of total N fertilizer added or 67% for IP and 76% for FP of total-N surplus, respectively. The calculation of potential nitrate concentration (PNC) at 1 m soil depth at the end of the third season showed a high concentration with significant different of IP and FP having mean value of 59.8 and 82.5 mg N L-1. From the gathered data it was obvious that over N fertilization had negative effect to agricultural environment