Siam weed growing in any locations can be used for developing organic agriculture in Indonesia. The research was to find the quantitative and qualitative potential of siam weed as compost material for organic shallot cultivation. This study was descriptive-quantitative research using survey method done in four regencies in Yogyakarta Special Province and laboratory analysis. Purposive random sampling was used in survey method to determine the samples by applying random sampling and nested design. Laboratory analysis was to know nutrient content of siam weed. Shallot was planted using siam weed compost of 10 and 20 ton ha-1, inorganic fertilizer of 500 kg NPK Mutiara 16-16-16 ha-1 and the control. Siam weed was potential for developing organic shallot in Indonesia. Siam weed produced fresh biomass of 80 ton ha-1 with the population density of 24-37 individual m-2 and spread over almost all locations in Yogyakarta Special Province. Siam weed also contained higher nutrients of 2.56% N, 0.38% P, and 2.41% K with C/N ratio of 19.52 under the critical point of 30 so that easy to mineralized. The use of siam weed compost stimulated leaf number on shallot at 7 weeks after planting compared to the use of inorganic fertilizer and the control, but gave no significant yield of 19.71, 15.56, and 18.92 ton ha-1 of bulb, respectively.Keywords: organic fertilizer, development, nutrient

Pot experiments have been carried out to investigate the distribution pattern of Phosphorus in oil palm seedlings axillary axes using 32 P radioisotope technique. The experiment was conducted in the greenhouse at the Center for Application of Isotope and Radiation -National Nuclear Energy Agency, Jakarta, Indonesia. KH 2 32 PO 4 solution with the activity of 5 mCi was injected into five points viz through the lowest, middle, upper leaf axil, at the base of the trunk and the soil 5 cm from the trunk. The method used was randomized complete block design with two replications.The 32 P uptake is expressed in counted per minute (cpm) counted by Liquid Scintillation Counter then transformed to disintegration per minute (dpm). The results showed that at the injection point in the lowest leaf axil, the distribution of 32 P was more towards the crown before heading towards the roots. In the middle of the leaf axil, the distribution of 32 P was recorded higher, nutrients were actively distributed to the top of the plant while the roots were very low. The dynamics of 32 P at the upper axil injection point, the highest 32 P uptake at the start of the injection was seen in the lowest leaf axil. The 32 P distribution then leads to the stem, roots and finally to the canopy. At the injection point in the soil 5 cm from the trunk, the counted value shows 32 P distributed to the top of the plant, while at the base of the trunk, 32 P is distributed to the farthest injection point, the plant canopy. From this study, it can be concluded that 32 P radioisotopes can describe the distribution of nutrients in plant parts, wherever radioisotope is applied. Phosphorus can be applied through any leaf axil and can be distributed well to the canopy of plants.

Increasing production cost of conventional shallot cultivation has promoted organic shallot production to develop by using natural resource potential such as siam weed that can found everywhere in Indonesia. This research was done to determine the best combination of siam weed compost and biocontrol agent of avirulent Fusarium oxysporum f. sp. cepae for organic shallot cultivation. Shallot was cultivated by applying various combination of siam weed compost and the biocontrol agent with inorganic fertilizer application of Mutiara 16-16-16 as the control. The combination were 20 ton/ha of siam weed compost combined with 36.8 kg/ha of the biocontrol agent, 20 ton/ha of siam weed compost combined with 73.6 kg/ha of the biocontrol agent, 10 ton/ha of siam weed compost combined with 36,8 kg/ha of the biocontrol agent, and 10 kg/ha siam weed compost combined with 73.6 kg of the biocontrol agent. The results showed that shallot cultivation using siam weed compost combined with the biocontrol agent gave better growth and increased the shallot yield by 26% compared to the use of inorganic fertilizer of Mutiara 16-16-16.

Fertilization costs for almost all oil palm plantation companies range from 40-60% of the total plant maintenance costs. Farm fertilizer consumption and world fertilizer prices for the three main macronutrients increase yearly, but the use efficiency is low. Meanwhile, pressure came from environmentalists regarding the effects of pollution by excessive use of fertilizers. Application of fertilization through axillary oil palm midrib is expected to overcome inefficiency. This study examined the phosphorus uptake of three-year-old oil palm leaves on the application of diammonium phosphate fertilizer through two positions of the axil, the top and bottom, with four dosage levels, namely 200. 250. 300 and 350 grams per tree. The split-plot design method was used in the research conducted at PT Bumitama Gunajaya Agro oil palm plantation, West Kalimantan. The results showed that Phosphorus uptake was relatively the same in all leaf axil positions and doses and control with the highest dose of 350g/tree through the soil. The results indicate that fertilization of oil palm is possible to do through any axils with a lower amount than it through the soil.