Abstract: Hyacinth (Eichhornia crassipes) is considered a weed in the water and can act as an absorbent to absorb heavy metal lead (Pb) derived from agricultural activities, vehicle waste, and domestic waste. This study aims to analyze lead (Pb) in hyacinth in Tolour, Eris, Tasuka, and Kaweng villages around Tondano Lake. The method used Atomic Absorption Spectrophotometry using dry ashing technique is then ready for analysis using Titan 100 MPS (PERKIN ELMER, USA) and its analysis tool Atomic Absorption Spectrophotometer (AAS) PERKIN ELMER PinAAcles 900F. In this analysis, using dry acid with optimal acid used 65% HNO3 as much as 10 ml. From this study, it can be seen that the pollution of heavy metals (Pb) in Tondano Lake is still quite low supported by the results obtained at each location and part of the plants tested. At the location of Eris, the results were quite high both at the roots of 2.36 x 10-4, stem 2.28 x 10-4, and leaves 2.58 x 10-4. Thus it can be concluded that the hyacinth plant in the waters of Tondano Lake can reduce heavy metal pollution (Pb).

Abstract: Corn is a fairly important commodity in North Sulawesi. Corn is used as a second food and as animal feed. Some people in North Sulawesi prefer local maize to superior corn. High public demand was not balanced with Manado yellow corn production which continued to decline. Therefore, it is necessary to strive to increase the production of corn plants with proper nutritional quality as food and animal feed ingredients. The purpose of this study was to obtain the right dosage of fertilizer N on growth, yield, and quality of local Manado yellow corn plants. For this reason, the effect of urea (N) on growth, production, and local corn yields of Manado yellow was carried out, indicating that maize crops that were not fertilized produced lower growth, production, and quality of corn than plants fed with urea fertilizer (N). In conclusion, the interaction of the treatment of urea fertilizer at a dose of 300 kg ha-1 gave the best results in plant growth with a plant growth rate of 204.70 g.m-2 ha-1, production of 3.24 t ha-1, and quality of corn seeds namely starch content 47.43 %, total sugar content of 3.91% and carotenoid levels of 1.67 mg/g.