University Of Lampung Journal Publication
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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
Pemanfaatan Tithonia Diversifolia pada Tanah Sawah yang Dipupuk P Secara Starter terhadap Produksi serta Serapan Hara N, P, dan K Tanaman Padi
Full text linkThe research of Tithonia diversifolia utilization in the paddy soil that was fertilized P-starter on yield and N, P, K uptake on rice crop, has been conducted from August to December 2005. The objective of this research was to determine interaction between P-starter levels, and tithonia levels on production and N, P, K element uptake of rice crop. The research was pot experiment in the green house in factorial design 4 x 4. First factor was 4 levels of tithonia with reduce dosage fertilizer aplied (T0 = 0 t tithonia + 200 kgUrea ha-1 + 75 kg KCl ha-1; T1= 2,5 t tithonia ha-1 + 150 kg Urea ha-1, without KCl; T2 = 5,0 t tithonia ha-1 + 100 kg Urea ha-1, without KCl; dan T3 = 7,5 t tithonia ha-1 + 50 kg Urea ha-1, without KCl). The second factor was 4 levels of P-starter (0, 2, 4, and 6 kg P ha-1). The result showed that combination T3 treatment and 2-4 kg P-starter ha-1 increased the grain yield 20,51-21,08 g pot-1 (18,65-19,21%). Effect of T3 treatment was not significant with T2 treatment on the grain yield. The best interaction was T3 treatment on N and K uptake ((0,84 g pot-1 for N, dan 0,82 g pot-1 for K).
Existing Versus Added Soil Organic Matter in Relation to Phosphorus Availability on Lateritic Soils
No full textLateritic soils (Ultisols and Oxisols) are commonly characterised by high phosphate sorbing capacity due to the type of clay and present high content of aluminium (Al) and iron (Fe) oxides. Addition of fresh organic matter (OM) may contribute to management of these soils by releasing more bicarbonate-extractable phosphorus (BP) through organic phosphorus (OP) transformation, or by the soluble component of OM additions desorbing phosphate by ligand exchange. It is not known, however, whether BP results solely from addition of new OM (by either mineralisation or desorption) or from transformation of inherent or pre-existing in soil. We considered that removing the existing soil OM and replacing it with an equivalent amount of new OM may help to resolve this issue, especially with respect to P transformation after OM additions. Three lateritic soils of Western Australia (including a deep regolith material with very low inherent soil OM (SOM)) were used, and sub-samples of the three soils were combusted (450° C) to obtain soils effectively free from existing OM. A further sub-sample of the soils was not combusted. Both soil groups, receiving the same amount of organic carbon (OC, from 80 ton ha-1 biomass + soil OM or biomass equal to soil OM) from peat, wheat straw (Triticum aestivum L.) and lucerne hay (Medicago sativa L.), were incubated for nine months. Soil bicarbonate-extractable P as well as non-extractable P (NP, measured as Total-P (TP)-BP) increased due to new OM application in the order lucerne hay>peat>wheat straw. The correlation between BP with soil organic carbon (SOC) became more positive over time. Microbial biomass phosphorus (MBP) was not well correlated with the increase of NP content and phosphatase was not related to the increase in BP. Overall, freshly applied (new) OM not only contributed to the increased level of P compared with the existing OM treatment
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