Robiyanto Hendro Susanto

Fire and land use effects on biodiversity in the southern Sumatran wetlands

We studied the long-term effects of an intensified fire regime following logging and altered land use practices on the biodiversity and successional dynamics of forests on three sites (Sugihan, Mesuji, and Pampangan) of roughly 300 km2 each, distributed across the continuous wetland ecosystem of southern Sumatra. Satellite image analysis and ecological and socio-economic surveys were combined to reveal the vegetation characteristics, and links to fire, land use history, and site conditions.

Developing Seasonal Operation for Water Table Management in Tidal Lowland Reclamations Areas at South Sumatera Indonesia

This research was completed using mixed qualitative and quantitative methods. Field surveys were executed in sugar cane plantation throughout South Sulawesi Indonesia. Land suitability analyses were performed using a parametric approach with Storie’s index equation followed up with correlation analysis using the Pearson correlation. Results revealed that the period for sugarcane crop growth in the humid tropic relatively dry regions of South Sulawesi Indonesia lasted for the months of November to July. The land suitability for sugar cane in the research location was moderately suitable (S2c) and marginally suitable (S3c, S3s, S3s,f and S3c,w) with limiting factors such as relative humidity during crop maturation phase, the duration of sunlight, soil depth, soil texture, soil pH and soil drainage. Land suitability index at the research location ranged from 25.2 to 55.0; sugar cane yields ranged from 30.3 to 62.0 Mg ha year. Pearson correlation coefficient (r) between LSI with cane and sugar productivity were 0.81 and 0.84 respectively, signifying the strength of the correlation between the two values. This also indicates that land suitability index can be estimating the potential crop yield in the humid tropicsthat relatively dry climate regions.Field experiment with a split plot design has been carried out in order to assess the growth characteristics and yields, and effectiveness of MVA upland rice which were given potassium fertilizer in two growing seasons. MVA inoculation consisted of three treatments (without MVA, Glomus sp. and Gigaspora sp.) while potassium fertilizer consisted of five levels (0, 12.5, 25, 37.5, and 50 kg ha-1 K). The results showed that plant growth variable which was inoculated by MVA at any levels of K fertilizer was higher in the dry season than that in the wet season, whereas the opposite occurred for net assimilation rate. Potassium content of leaf tissue, shoot/root ratio, and grain weight per hill was determined and mutually dependent on genus MVA, dosages of K fertilizer, and growing season. Harvest index and grain dry weight per hill were influenced by the growing season and the genus MVA but the effect did not depend on each other. At all dosages of K fertilizer and any MVA genera, Gigaspora sp. inoculation was better than that of Glomus sp. Dry weight of grains per hill was affected by the contribution of grain content per hill, weight of 1000 grains and number of productive seedlings per hill. The optimum dosage of K fertilizer in the dry season was 32.4 kg ha-1 K with grain yield 3.12 Mg ha-1 for inoculation of Gigaspora sp., whereas the optimum dosage in the wet season was 34.2 kg ha-1 K for the treatment Glomus sp. inoculation with Gigaspora sp. in the wet season did not reach dosages of optimum K fertilizer. Keywords: Harvest index, MVA, potassium fertilizer, upland rice [ How to Cite : Natawijaya D. 2012. Increasing Growth and Yield of Upland Rice by Application of Vesicular Arbuscular Mycorrhizae and Potassium Fertilizer. J Trop Soils 17 (1): 53-60. doi: 10.5400/jts.2012.17.1.53] [ Permalink/DOI: www.dx.doi.org/10.5400/jts.2012.17.1.53 ]This study aimed to examine Organonitrofos Plus fertilizer (OP) on sweet corn (Zea mays Saccharata L.) and its effect on changes in soil chemical properties of Ultisols. Organonitrofos Plus fertilizer is an enhancement of Organonitrofos fertilizer enriched with microbes at the beginning of the manufacturing process. Research was conducted in the greenhouse of Integrated Agricultural Laboratory of Lampung University. Treatment applied was a factorial of 4 t 2 t 3 with three replications in a randomized block design. The first factor was the dose of OP fertilizer (0, 10, 20, 30 Mg ha-1), the second factor was the dose of inorganic fertilizers (without inorganic fertilizers, and with inorganic fertilizers, namely Urea 0.44, 0.28 SP-36 and KCl 0.16 Mg ha-1), and the third factor was the dose of biochar (0, 10, 20 Mg ha-1). By a single OP fertilizers, inorganic fertilizers, and the interaction between the OP and the inorganic fertilizers increased the weight of dry stover, cob length, cob diameter, cob with husk and cob without husk of corn. OP fertilizers which are applied in Ultisols can improve soil fertility and increase corn production so that OP fertilizer can lessen the use of inorganic fertilizer and can be used as a substitute for inorganic fertilizer. RAE values were highest in treatment of O4K2B2 (30 Mg OP ha-1, with inorganic fertilizer, 10 Mg biochar ha-1) that was equal to 181%, followed by O2K2B3 (10 Mg OP ha-1, with inorganic fertilizer, 20 Mg biochar ha-1 ) with the difference in RAE value of 0.5%.[How to Cite: Dermiyati, SDn Utomo,n KF Hidayat, J Lumbanraja, S Triyono, H Ismono, NEn Ratna, NT Putri dan R Taisa. 2016. Pengujian Pupuk Organonitrofos Plus pada Jagung Manis (Zea mays Saccharata. L) dan Perubahan Sifat Kimia Tanah Ultisols. J Trop Soils 21: 9-17 Doi: 10. 10.5400/jts.2016.21.1.9][Permalink/DOI: www.dx.doi.org/10. 10.5400/jts.2016.21.1.9]Coco rind is a waste that if not used can cause environmental problem around the plantation. One way to utilize cocoa rind is by making it into compost which can be used as organic fertilizer. Different planting distance will affect on the number of plant population per unit area and will indirectly affect the absorption of nutrients, water and other growth factors. The purpose of this study was to determine the effect of the utilization of compost from cacao rind waste on the growth of Saccarum edule Hasskarl plant with different planting distance. The design used was to factor randomized block design with 2 replications, then there are 18 treatment combinations. In this research, the first factor of cacao rind composts comparison with cow manure consisted of three levels, they are: P1 = 50 kg; 10 kg; P2 =50 kg: 30 kg; P3 = 50 kg: 50. While the second factor uses the planting distance which consisted of three levels, they are: J1= 100 cm X 150 cm; J2= 100 cm X 100 cm; J3= 100 cm X 50 cm. Based on the research results, it shows that the best treatment of cocoa rind compost and cow manure, which affects on the number of buds is treatment P3 on 5 WAP, while the best used for the plants’ height is P2 on 3 WAP, and the best used for the leaves’ length is treatment P2 on 2 to 4 WAP.

Utilization of Freshwater Fish Biodiversity as Income Source of Poor Rural People (Case Study in Pampangan Subdistrict of South Sumatra Province, Indonesia)

South Sumatra Province is covered by 1.1 million hectares of swamp land, which were considered as marginal land due to wet and muddy conditions as well as the presence of wild animals. During the wet season, the swamp ecosystem becomes a productive fishing ground, providing fish resource for neighboring communities. So this productive area constitutes a source of income for fishermen in the area. The current system categorizes the swamp area in Pampangan subdistrict into three types according to the source of water. Overall, the swamp is inhabited by 46 species of fishes and prawn. Type-2 swamp is populated by 31 species, while a number of 27 and 16 species were found in the type-3 and type-1 swamp, respectively. Type-2 swamp comprises the highest diversity. Resource allocation for fisheries is managed by the local government into 21 water bodies with artificial border. Each water body is exploited by a group of two to ten fishermen using various fishing gears, the most effective of which is a barrier with box trap (lulung). Using this fishing gear, the production might reach around 624,170 kg of fish per year. This gear seems to be a nonselective gear which catches 23 fish species. The other type, i.e., the longline (rawai), is the most selective gear which catches only seven carnivorous fish species. Data collected from this study indicates that fish yield is variable among water bodies from 15,000 kg per year in Lebung Asem to 220,900 kg per year in Rasau Jungkal, depending on ecological conditions in the swamp. Thus, the management of fishing activity would be very important in keeping fish biodiversity and in order to increase the fish yield; therefore, the income of fishermen might be increased.

POLA PENGELOLAAN RAWA LEBAK BERBASIS KETERPADUAN EKOLOGI EKONOMI- SOSIAL-BUDAYA UNTUK PEMANFAATAN BERKELANJUTAN

Rawa lebak merupakan ekosistem yang dinamis, mengalami perubahan dua arah dari sistem akuatik ke sistem terestrial, dipengaruhi oleh faktor-faktor hidrologi, mutu air, vegetasi, fauna, kepemilikan dan pemanfaatan. Penelitian ini dilaksanakan di rawa lebak Kecamatan Pampangan Kabupaten Ogan Komering Ilir Provinsi Sumatera Selatan, bertujuan untuk merumuskan pola pengelolaan rawa berbasis keterpaduan (integrated system) antara ekologi, ekonomi dan sosial budaya. Pengamatan karakteristik hidrologi, ekologi, pola pemanfaatan, sosial dan budaya menunjukkan bahwa tipologi rawa lebak di lokasi penelitian dapat dibagi tiga yaitu rawa banjiran, rawa tadah hujan dan rawa campuran. Dari hasil analisis keterkaitan faktor internal dan eksternal, penilaian untuk rawa tadah hujan adalah 104 sedangkan rawa banjiran dan rawa campuran masingmasing 68 dan 45. Pola pengelolaan yang dapat disarankan untuk rawa tadah hujan diarahkan pada mempertahankan kekhasan ekosistem dengan pemanfaatan bagi sektor perikanan dengan kegiatan tambahannya adalah pertanian dan peternakan. Pada rawa banjiran diarahkan pada kegiatan pertanian dengan kegiatan lainnya adalah perikanan dan pertanian tergantung pada musim dan ketersediaan air, dan pada rawa campuran diarahkan pada peningkatan efisiensi pemanfaatan air dengan menyediakan lebung dan penyerasian pola tanam dengan daur banjir. Lebak swamp is a dynamic ecosystem, seasonally changed from aquatic to terrestrial ecosystem vice versa. Swamp functions were influenced by charateristic of hydrobiology, water quality, vegetation, wild animal, property right and utilization. The research conducted in lebak swamp of Pampangan Subdistrict, Ogan Komering Ilir District, South Sumatra Province to know environmental characteristic as components to builtd management scheme of those swamp dealing with integrated system between ecology, economy and socio cultural. The characteristics of hydrobiology, ecology, utilization, sociocultural show that in research location, the swamp could be divided into three types,i.e., floodplain swamp, rain-fed swamp and mixed swamp. The result shows that relationship between internal and external factor with ecosystem services gave value of 104 for rain-fed swamp, while floodplain and mixed swamp were 68 and 45 respectively. Suggested management scheme for rain-fed swamp with high ecology score as more natural swamp ecosystem is a fishing area with additional utilization as agricultural land and animal husbandry. Floodplain swamp can manage for agricultural land with additional activity fisheries and animal husbandry depending on season and water table. The management for mixed swamp can suggested primarily on water conservation by preparing fish pool and planting pattern due to maintain water table for agriculture use during dry season.

The study water table fluctuation in tidal lowland for developing agricultural water management strategies: (A case study for corn cultivation after rice)

The research objective is to evaluate the water status in the tertiary block of tidal lowland for developing water management strategies and cropping pattern for food crop agriculture. The field study was conducted at reclaimed-tidal lowland areas having A typology (wet) located at Telang Karya Village, Primer 8, Delta Telang I. The method used was field action research. Corn was cultivated as a second crop indicator. For corn cultivation, the soil condition should be dry in which the water should be at the depth of 40–50 cm. The main point for network improvement is by construction of water gates at tertiary canal. These water gates are capable to hold high tidal water which made low tidal water can be drained in longer period. This in turn created dry land condition for corn cultivation. Potential planting was at dry season about the last June or early July. The best land drainage design was by providing drainage spacing at 8 m and the depth of 20 cm. Field study showed that operation of water gates have function to drain water from land during low tidal water and to retain water during high tidal water. The opening of water gates for water supply was done 3–4 times after corn plants were two-weeks old, one month, and during early seed filling period. The water table height was kept at 60cm from soil surface in order to prevent the plant from experiencing water stress. Therefore the water management objectives for second crop were drainage option and in combination with control drainage. Supply water also required, especially in the early of flowering stage. The crop yield was highly potential with magnitude of 3–4 ton/ha and it was economically profitable because its B/C ratio was 1.4 which was close to the yield of rice cultivation farm enterprise