Effect of Jellyfish fertilizer on Seedling Growth and Soil Properties (第43回大会特集)
The excessive increase of jellyfish swarms could threaten the fishers and the marine food chain. The aim of research was to evaluate the potential benefit of the jellyfish as a fertilizer for different trees. The greenhouse experiment was conducted at Kutan, Chuncheon, South Korea using two tree species. Jellyfish was applied to soil before planting at different application rates (1.6, 2.7, 5.5, and 11.1 g/kg). Generally, the addition of jellyfish fertilizer increased soil moisture contents. It is concluded that low application rate of jellyfish fertilizer increased soil moisture and nutrient contents, consequently, enhancing the seedling growth.
Preliminary Study on the Potential Usefulness of Jellyfish as Fertilizer
We will describe the potential usefulness of jellyfish (Aurelia aurita and Chrysaora melanaster), which have increased rapidly in coastal waters, as a fertilizer for vegetable fields. The jellyfish were found, by means of absorptiometry, flame photometry or ICP emission spectroscopy, to have five principal components of fertilizers: nitrogen, phosphorus, potassium, magnesium, and calcium. Concentrations of total nitrogen, total phosphorus, and potassium in Chrysaora melanaster (954, 153, and 667 mg/kg in fresh weight) were 2.8, 3.3, and 1.3 times higher than those in Aurelia aurita (336, 46, and 501 mg/kg), respectively. Concentrations of sodium, potassium, magnesium, and calcium were almost identical to those in seawater. Concentrations of chromium andcadmium in jellyfish were lower than the limit of quantification for ICP emission spectroscopy. Three kinds of vegetables, chingentsuai (a Chinese vegetable), green soybeans, and perilla were cultivated using a suspension of jellyfish as a fertilizer. Jellyfish are inferred to be effective for growth of vegetables, especially chingentsuai.
Soil water status influences plant nitrogen use: a case study
We studied differences in nitrogen use efficiency (NUE) among six species [Calamagrostis epigejos (L.) Roth., Carex duriuscula C.A. Mey., Phragmites communis (L.) Trin., Salix gordejevii Y.L. Chang, Salix cheilophila Schneid., and Typha minima Funk.] growing in two contrasting habitat types, i.e., a riverine wetland with high water supply and a riparian zone with low water supply. The two sites were different in soil water supply, but not in nitrogen supply. Here, NUE was defined as the total net primary production per unit nitrogen absorbed. There was no significant difference in NUE between the species growing in the riverine wetland (Carex duriuscula, P. communis, S. cheilophila, T. minima) and the species growing in the river bank (Carex duriuscula, Calamagrostis epigejos, P. communis, S. gordejevii). We further analyzed NUE as the product of the nitrogen productivity (A, the rate of dry matter production per unit of nitrogen in the plant) and the mean residence time of nitrogen (MRT, the period of time a unit of nitrogen is present in the plant). The species growing in the riverine wetland had larger A but lower MRT than the species growing in the river bank. There was an inverse relationship between A and MRT. Consequently, NUE was similar among species and habitats. These results suggested that environmental factors, such as soil water supply, can influence N use by plants.