Journal of Tropical Soils
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The Changes of Earthworm Population and Chemical Properties of Tropical Soils under Different Land Use Systems
Full text linkHilly area Sumberjaya, West Lampung Province, South Sumatra, Indonesia, is one of the Province where deforestation increasing in the past 30 years as a result of the implementation of agricultural systems, especially coffee plantation. it is important to study the soil fauna in these natural relicts. Six sites (3 naturals and 3 managed systems) were studied in order to identify earthworm species communities, using the hand sorthing method and soil chemical parameters (pH, avail-P, org-C., tot-N, and cation exchange capacity (CEC). Two species were found (Pheretima sp. and Pontoscolex sp.). All land use systems had very similar soil chemical characteristics, there can be characterised as acidic (pH between 3.6 and 5.0). A high content of organic carbon was in natural sites (bush 4.0 % and primary forest 3.9 %), and a low content was in managed sites (coffee plantation 2.1 %). Total nitogen (0.37 %) and CEC (21.84 Cmol-c kg-1) was in primary forest. However, the earthworm densities were significantly lower under primary forest than in the other sites. The acidity component explained mainly  the lowest earthworm population at the primary forest (soil pH 3.6). The use of succession forest (bush) and mix farming showed a positive effect on soil fertilit
Releasing Pattern of Applied Phosphorus and Distribution Change of Phosphorus fractions in the Acid Upland Soils with Successive Resin Extraction
No full textThe releasing pattern of applied P in the acid upland soils and the soil properties influencing the pattern were studied. Surface horizons of six acid upland soils from Sumatra, Java and Kalimantan were used in this study. The releasing pattern of applied P (300 mg P kg-1) of these soils were studied by successive resin extraction. P fractionation was conducted to evaluate which fractions released P to the soil solution after successive resin extraction. The cumulative of resin-Pinorganic (Pi) release of soils was fitted to the first order kinetic. Regression analyses using factor scores obtained from the previous principal components analyses was applied to determine soil properties influencing P releasing pattern. The results suggested that the maximum P release was significantly (P < 0.05) increased by acidity plus 1.4 nm mineral-related factor (PC2) i.e. exchangeable Al and 1.4 nm minerals (smectite and vermiculite) and decreased by oxide related factor (PC1) i.e. aluminum (Al) plus 1/2 iron (Fe) (by ammonium oxalate), crystalline Al and Fe oxides, cation exchange capacity, and clay content. P fractionation analysis after successive resin extraction showed that both labile and less labile in the form of NaHCO3-Pi and NaOH-Pi fractions, respectively, can be transformed into resin-Pi when in the most labile resin-Pi is depleted. Most of P released in high oxides soils were from NaOH-Pi fraction while in low oxides soils were from NaHCO3-Pi. P release from the former fraction resulted in the maximum P release lower than that of the latter one. When NaHCO3-Pi was high, NaOH-Pi was relatively more stable than NaHCO3-Pi despite resin-Pi removal. NaHCO3-Pi and NaOH-Pi are very important P fractions in replenishing resin-Pi in these acid upland soils
Local Rice Cultivars Grown On Tidal Swampland Near Coastal Area in South Kalimantan
Full text linkLocal farmers in South Kalimantan (Banjarese farmers) use to grow local rice cultivars. The local rice growing areas are varied with distance from the coastal line. Consequently, the degree of salinity also varied. To overcome the salinity problem, farmers do their last transplanting earlier than the farmers in the inland area and grow the local rice cultivars that they believe tolerant to salinity. In this study, we investigate the local rice cultivars grown by the farmers in the coastal areas. Sixty paddocks were selected in Pulantan, Aluh-Aluh, Simpang Warga and Bunipah Villages, Aluh-Aluh District, Banjar Regency, South Kalimantan. The rice yield of each paddock was estimated by sampling 3 x 5 hills in 3 replicates. The soil was collected within the 3 x 5 hills area and analysed their electric conductivity (EC) and pH. We found that there were four families of local rice cultivars grown, namely, Palas, Bayar, Pandak and Siam families. Among all local rice cultivars grown, it was revealed that Pandak Putih and Siam Unus produced the highest yields. However, according to the farmers, Palas and Bayar families are the common rice tolerant to salinity. The good price of Siam family and good yield of Pandak family at other paddocks might become the considerant of growing such rice families in the study site
Impact of Rainforest Conversion on Surface Runoff and Soil Erosion in Nopu Upper Catchment of Central Sulawesi
No full textRainforest conversion into agricultural lands in Nopu Upper Catchment such as cocoa plantations, maizes, cassava, peanuts, and scrub and bush were significantly increase soil erosions and surface runoffs, which in turn will decrease crops productivity and hydrologic functions of watershed. Soil erosion from maize and peanut rotation plots are higher 2.061,8% than soil erosions from natural forest plots. Soil erosions are higher also in intercroping young age cocoa, maize and cassava plots and maize plots respectively 2.023,8% and 2.012,3%.  Where as surface runoffs were increase up to 650,9% in medium age cocoa plots, 380,4% in intercroping young age cacao and cassava plots, and 347,1% in scrub and bush plots. The result of ANSWERS model simulation using daily C factors were indicate that rainforest conversion into agricultural lands in Nopu Upper Catchment causing soil and water loss respectively 3.190,5 ton/year and 115.441 m3/year.  Application of agroforestry systems in agricultural lands which in line with reforestation in stream line area of Nopu river and steepy agricultural lands (slope > 40%) are effectively reduce soil erosions up to 77,6% compare to soil erosion from existing land uses
Andisols from Tondano Area, North Sulawesi: Properties and Classification
No full textThree pedons of Andisol (TN-1, TN-2 and TN-3) developed from young volcanic materials of the Lokon, Soputan, and Lengkoan volcanoes respectively in the Tondano area, North Sulawesi, were studied in the field, and 18 soil samples were analysed in the laboratory for physical, chemical, and mineralogical properties, and they were classified according to Keys to Soil Taxonomy 2003. The results indicated that all the pedons meet the requirements of the andic soil properties, and thus classified into Andisol order. Pedon TN-1 meets bulk density < 0.90 g cm-3, P retention > 85%, and (Alo + 0.5Feo) content extracted by ammonium oxalate > 2.0%, while pedons TN-2 and TN-3 meet the requirements of P retention > 25%, (Alo + 0.5Feo) content > 0.4%, volcanic glass content > 5%, and value of [%(Alo+0.5Feo) x 15.625 + (% volcanic glass)] is > 36.25. Composition of sand mineral fraction indicate that pedon TN-1 and TN-3 show andesitic to basaltic volcanic materials, whereas pedon TN-2 with high olivin content belongs to basaltic volcanic materials. Clay minerals of all the pedons was dominated by hydrated-halloysite with few of disordered-kaolinite, which indicated a little weathering of the pedons. The pedons were classified at family level as Typic Hapludand, medial, amorphic, isothermic (TN-1), Humic Udivitrand, ashy, amorphic, isothermic (TN-2), and Alfic Hapludand, medial, glassy, isothermic (TN-3)
Relationship between depth of soil moisture assessment and turgidity of coffee plant in selected agroclimates
Full text linkObservation on the relationship between the depth of soil moisture assessment and turgidity of coffee plant has been carried out at 3 different agroclimates by survey method, i.e. Andungsari experimental station (Andosol soil type, >1.000 m asl. high, and rainfall type of C), Sumberasin experimental station (yellowish-red Mediterranean soil type, 450-500 m asl. high, and rainfall type of C, and Kaliwining experimental station (low humic glei soil type, 45 m asl. high, and rainfall type of D) in order to assess the depth of soil moisture through soil profile influencing turgidity of coffee plants at three different agroclimates.   The method of assessment is by fitting the relationship between the depth of soil moisture assessment and turgidity of coffee plant and their determination coefficients through the period of dry season up to early rainy season.  Plant turgidity is evaluated from its relative water contents of the leaves sampled periodically at the same time as observation of soil moisture content. Plant turgidity is affected by soil moisture condition up to a certain depth which looks to be typical of the agroclimates. At Andungsari experimental station (high land) it is necessary to assess soil moisture through the soil profile up to 100 cm deep in order to evaluate water stress of the plants; inversely, at Kaliwining experimental station in order to evaluate water stress of the plants it is just justified from the soil moisture condition of the soil surface layers (0-25 cm). Whereas at Sumberasin experimental station water stress of the plants could be predicted from soil moisture assessment of the surface layer depth or through the deeper layers of the soil profile either. Andungsari-1 and Lini S-795 clones are more resistant to drought than Kartika-2 clone at Andisol soil type with C rainfall type and elevation > 1000 m asl.  BP-308 clone showed its response as relatively resistant to drought at yellowish red Mediterranean soil type with C rainfall type at elevation around 500 m asl.  Robusta coffee clone with no name at Kaliwining experimental station showed wilting sign, reduction of its turgidity, and falling leaves during the dry season, and positively responding to soil moisture increase.  An effort to maintain plant turgidity with increasing soil water stress could be done by managing atmospheric demand to be lower. Practical implications of the findings might be discussed a bit more deeply in this paper.Â