Studi tentang tinggi penempatan lampu terhadap jumlah hasil tangkapan ikan pelagis di rumpon di Perairan Likupang (Study of the placement level of lights on the number of pelagic catches at FADs in Likupang Waters)

Fishing aids commonly used in fishing operations in Indonesia include FADs and light attractors. The use of lighting fishing is generally intended to attract fish to gather around light sources. The success of the light source to attract and collect fish around the lamp depends on the state of the lamp and environmental conditions. In this study treatment was is the height of the lamp from the water surface, namely 80 cm, 120 cm, and 180 cm. 120 cm high is the height commonly used by fishermen. The lights are made in two series, each consisting of four lights with a total of 200 watts. The purpose is to find out the catch of fishing rods around the FADs with high treatment of lights that are dissected. Based on the graph, the treatment given has a different tendency in catches number. The types of fish caught by hand line in FADs around 5 types of fish in the order of the most catches are mackerel (Selaroides leptolepis), and followed by flying fish (Decapterus ruselli), tuna fish (Auxis thazard), dolphin fish (Coryphaena hippurus), and squid (Loligo sp).The lamps placed at the level of 180 cm gives more catches, followed by the lamps at thelevel of 80 cm which is not much different from an level of 120 cm. cm and type of flying fish was caught more at the height of the lamp at 180 cm from the surface.Keywords: LED lights, FADs, pelagic fish, Likupang waters AbstrakAlat bantu penangkapan yang umum digunakan dalam operasi penangkapan ikan di Indonesia antara lain adalah rumpon dengan attractor cahaya. Penggunaan alat bantu cahaya pada penangkapan ikan umumnya dimaksudkan untuk menarik ikan agar berkumpul di sekitar sumber cahaya. Berhasil tidaknya sumber cahaya lampu untuk menarik dan mengumpulkan ikan-ikan di sekitar lampu tergantung keadaan lampu dan kondisi lingkungan. Perlakuan pada penelitian ini adalah tinggi lampu dari permukaan air, yakni 80 cm, 120 cm, dan 180 cm. Tinggi 120 cm merupakan tinggi yang biasa digunakan oleh nelayan. Lampu dibuat dalam dua rangkaian yang masing-masing terdiri atas empat lampu dengan intensitas total 200 watt. Tujuan untuk mengetahui hasil tangkapan pancing ulur di sekitar rakit dengan perlakuan tinggi lampu yang berbedah. Berdasarkan grafik, perlakuan yang diberikan memiliki kecenderungan berbeda. Jenis-jenis ikan yang tertangkap dengan pancing ulur di rumpon adalah 5 jenis ikan dengan urutan hasil tangkapan terbanyak adalah selar (Selaroides leptolepis), dan diikuti oleh ikan layang (Decapterus ruselli), tongkol (Auxis thazard), lemadang (Coryphaena hippurus), dan cumi-cumi (Loligo sp). lampu yang ditempatkan pada ketinggian 180 cm memberikan hasil tangkapan yang lebih banyak, diikuti lampu pada ketinggian 80 cm yang tidak jauh berbeda dengan ketinggian 120 cm. Jenis ikan selar diperoleh paling banyak pada ketinggian 120 cm dan jenis ikan layang lebih banyak tertangkap pada ketinggian lampu 180 cm dari permukaan.Kata kunci: lampu LED, rumpon, ikan pelagis, perairan Likupan

L3: On Farm systems and risk management

This project seeks to define the interplay between market access, crop and livestock technologies, and investment risks in water- and market-scarce environments that leads to technology adoption by farm families, enabling them to enhance food security and incomes through more efficient water use. Water efficient farm enterprises and climate risk management Innovation Platforms will be established at project sites to bring together all role players necessary to increase investments in farm management strategies to improve productivity of crop and livestock systems through improved fodder production. Investment choices matched to farmer capacities and climatic risk environment Understanding how the capacity of farmers and their ability to make use of new opportunities is affected by their wealth status, investment priorities and variable climate will assist in the design of new and more target-specific crop-livestock management strategies. Market-led technologies for smallholder farmers developed and tested The project will use market access as the driver of crop and livestock technology uptake. Market development initiatives such as contract farming, voucher-based input distribution schemes for seed and fertilizer and innovative fertilizer marketing strategies will be implemented by project partners, technically supported by research and extension and monitored for impacts across the value chain

Formulating crop management options for Africa’s drought-prone regions: Taking account of rainfall risk using modeling

Few smallholder farmers in Africa’s extensive semi-arid regions use fertilizer and virtually none use recommended high levels of application. Essentially, Africa’s farmers have ignored the formal fertilizer recommendations of national research and extension systems. Because of this, productivity gains from fertilizer use remain grossly under-exploited. The existing fertilizer recommendations are one clear example of an information constraint that has proven intractable, despite more than 15 years of farmer participatory research in Africa. Due largely to training, researchers are generally preoccupied with identifying and reporting only the best option – the near-maximum yield result. While such optima may be correct from an agro-climatic perspective, in drought-prone regions, the risk associated with seasonal rainfall variations can determine whether or not farmers are likely to adopt a new technology and in what form. Yet, almost no research and extension recommendations given to farmers in Africa include any estimates of the variability in technology response that can be expected due to climatic risk. ICRISAT and partners have been pursuing a range of improved crop management options for the semi-arid tropics through crop systems simulation and farmer participatory research. This chapter presents some examples of how the application of crop modeling can provide a cost-effective pathway to formulation of crop management options under variable rainfall conditions and for farmers with a range of resource constraints. It includes examples of fertilizer recommendations, crop cultivar selection, and residue management in semi-arid region

Evaluation of Resource Management Options for Smallholder Farms Using an Integrated Modelling Approach

Farm-level analysis of trade-offs between soil fertility management alternatives is required to improve understanding of complex biophysical and socio-economic factors influencing decision making in smallholder farming systems and to identify opportunities for improving resource use efficiency. A farm characterization tool (IMPACT) linked to a generic optimization model (Household) was used to evaluate resource use on farms in contrasting wealth categories. The Household model optimized the net cash income for the farms (accounting for all on-farm and off-farm income, costs of production and expenditure for the households). Alternatives for management of nutrient resource were simulated using other models; APSIM for the crop production and RUMINANT for the livestock component. The output from the simulation models was fed into the Household model and evaluated within the biophysical and socioeconomic boundaries of the farms. Analysis of the performance of a poor farmer by IMPACT indicated a yearly net cash balance of US$-7 per annum (after all needs had been taken care of), mainly due to negative returns from the cropping system. The farmer relied on donated food and fertilizers. The cash balance was negative, even though she also worked for other farmers (i.e. sold labour, about 10 days a month during six months of the crop growing season) to generate income. The net income of the poor farm would be increased to US$81 per annum and the N balance from 7 kg ha-1 yr-1 to 10 kg ha-1 yr-1 by expanding the area allocated to groundnut from the current 5% to 31%. This would, however, generate a huge demand in labour in the current year (extra 46-man days) and reduce the P balance from 0 to -1 kg ha-1 yr-1. Maize could be managed more efficiently on the poor farm by cultivating a smaller, well-managed area. A wealthy farm household with a maize dominated cropping system had a net cash balance of US$210 per annum, mainly from sale of crop products. Under current resource management, the net cash balance could be increased to US$290 per annum by optimization of household energy and protein consumption. The net cash balance for the wealthy farm would be further increased to US$448 per annum, and nutrient balances to 271 kg N ha-1 and 30 kg P ha-1 by expanding the management strategy where maize was grown with a combination of cattle manure and ammonium nitrate fertilizer. To do this, the farmer would need to source more manure (or improve capture and the efficiency with which nutrients are cycled through manure) and invest in 110 man-days extra labour. Expansion of the area grown to groundnut without fertilizer inputs to a third of the farm would reduce net cash balance by US$11 compared with the current crop allocation due to poor groundnut yield. This would also increase labour demand by 155 mandays. Groundnut intensification on the wealthy farm would be more economic and labour effective if a small area was grown with basal fertilizer (7%N, 6%P, 8%K). Despite reducing nutrient balances for the arable plots, feeding groundnut residues to lactating cows increased net cash balance by 12-18% for the current year through increased milk production. The integrated modelling approach was useful for linking biophysical and socio-economic factors influencing decision making on smallholder farms and evaluating trade-offs for resource use in terms of nutrient balances, labour use, food sufficiency and cash balance.Farm Management, Resource /Energy Economics and Policy,

The APSIM manure module: improvements in predictability and application to laboratory studies

应用RACE方法获得斜带石斑鱼膜结合型免疫球蛋白M（membrane-bound immu-noglobulin M,mIgM）,膜结合型免疫球蛋白D（mIgD）,分泌型免疫球蛋白Z（secretory immu-noglobulin Z,sIgZ）的重链基因。斜带石斑鱼膜结合型IgM重链恒定区包含3个恒定区结构域（μ1,μ2,μ3）以及两个跨膜外显子（TM1,TM2）,TM1外显子与μ3结构域末端相连接。氨基酸序列相似性分析结果显示,斜带石斑鱼mIgM各恒定区与牙鲆mIgM恒定区相似性最高,为53%-78%。mIgD的cDNA全长为3 375 bp,开放阅读框包含3 006 bp,其恒定区由1个μ1外显子,7个δ外显子以及跨膜区组成。斜带石斑鱼IgD恒定区与鳜IgD各恒定区氨基酸序列相似性最高,δ1-δ7的相似性分别为75.5%、75.8%、65.4%、76.6%、88.1%、90.6%、82.8%,TM结构域为82.7%。sIgZ的基因结构与其他硬骨鱼类sIgZ的结构相似,包括4个外显子和3个内含子,内含子长度分别为222、129和458 bp。利用半定量PCR分别检测了这3种基因在斜带石斑鱼各器官/组织中的表达,发现mIgM在头肾、肾脏、脑、脾脏、肠、鳃、心脏和胸腺中均有表达;mIgD的mRNA在头肾、肾脏以及胸腺中有较高的表达,在肠中表达量较低;sIgZ mRNA主要分布于淋巴组织如头肾、肾及脾脏中,而在鳃、心脏和胸腺中的丰度较低