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Ladiyani Retno Widowati, Ladiyani Retno
Balai Penelitian Tanah Jl. Tentara Pelajar 12, Bogor 16114
Agriculture, Biological Sciences & Forestry Environmental Science

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The Rule of Organic Fertilizer on Fertilizer Efficiency and Requirement Rate for Vegetable Crop on Inceptisols Ciherang, Bogor Widowati, Ladiyani Retno
JOURNAL OF TROPICAL SOILS Vol. 14 No. 3: September 2009
Publisher : UNIVERSITY OF LAMPUNG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5400/jts.2009.v14i3.221-228

Abstract

Utilization of organic fertilizer is an alternative to increase soil health and supply a small amount of plant nutrient. Meanwhile agricultural soil in Indonesia commonly have low organic carbon content (<2%) therefore application of organic fertilizer is recommended. Based on that, the aim of the research is to measure the effectiveness of organic fertilizer on caisim (Brassica chinensis L.) growth, to measure the release of  N-NO3- and N-NH4+, to determine the recommendation of organic fertilizer for caisim on Incentisols Ciherang, Bogor. The research had been conducted at Research and Soil Testing Laboratory and green house of Soil Research Institute, Laladon – Bogor on April to July 2008 using soil sample of Inceptisols Ciherang, Bogor.  The treatments were:  Control (No fert.), NPK, rates of NPK + 500 kg organic fertilizer, 500 kg and 1000 kg organic fertilizer (No NPK), NPK+250 and 750 kg organic fertilizer. The five replications research had been conducted with Completely Randomized Design. The result indicated thats: (1) NPK fertilizer increased with addition of organic fertilizer approved by the evidence of increasing of  plant high 2-10%, leaves number 1-2%, and crop production 16-36%. The relative agronomic effectiveness (RAE) of treatment NPK+various rate of organic fertilizer were higher than NPK alone with value of 136-181%. (2) The release of NH4+-N and NO3--N from anorganic  fertilizer (NPK treatment) in four weeks incubation period  showed balance proportion with N rate. Nitrogen released from organic fertilizer in the same incubation period are 5.39 mg  NH4+-N kg-1 and  12.39 mg NO3- -N kg-1.  (3) The best organic fertilizer rate based on fertilizer curve for Inceptisols Cicadas-Bogor  having low C and N-organic is 560 kg organic fertilizer + NPK (300 kg Urea ha-1; 50 kg SP-36 ha-1; 50 kg KCl ha-1) produce caisim 134 g bag-1.
Nitrogen Dynamics and Nitrate Leaching in Intensive Vegetable Rotations in Highlands of Central Java, Indonesia Widowati, Ladiyani Retno; Neve, Stefaan De
JOURNAL OF TROPICAL SOILS Vol. 21 No. 2: May 2016
Publisher : UNIVERSITY OF LAMPUNG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5400/jts.2016.v21i2.67-78

Abstract

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 &alpha; 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 &alpha; 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.
Dynamics of pH, Ferrum and Mangan, and Phosphorus on Newly Opened Paddy Soil having High Soil Organic Matter on Rice Growth Widowati, Ladiyani Retno; Sukristyonubowo, .
JOURNAL OF TROPICAL SOILS Vol. 17 No. 1: Januari 2012
Publisher : UNIVERSITY OF LAMPUNG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5400/jts.2012.v17i1.1-8

Abstract

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.
Co-Authors Neve, Stefaan De Sukristyonubowo, .