The demand for organic foods is increasing globally, but a key limiting factor to the production of organic greenhouse produce is the lack of certified liquid fertilizers. In this experiment, four organic fertilizers were produced using either acidic extraction, anaerobic digestion or both of ensiled biomass of organic red clover and white mustard. The resulting fertilizers were applied to greenhouse-grown parsley either alone, or in combination with nitrogen (N)-enriched water produced by flushing acidic water with ammonia, to determine their effect on plant growth and the nutrient concentrations of parsley. Six combinations of fertilizer treatments were included in the greenhouse experiment. Three treatments received either fertilizers derived from acidic extraction, anaerobic digestion or both and three treatments received fertilizers derived from acidic extraction combined with N-enriched water. Conventional inorganic liquid fertilizer, chicken manure extract and no liquid fertilizer (only water) were added as control treatments. A higher N-min (ammonium and nitrate) to potassium (K) ratio was found in fertilizers after anaerobic digestion compared to acidic extraction. All organic fertigation treatments resulted in high pH, high K and chloride concentrations and high NH4/NO3 ratios in the root zone. In addition, high electrical conductivity (EC), P, K and Mg concentrations were found when only acidic extracted fertilizers were applied. Application of plant-based organic fertilizers without amending with N-enriched water resulted in biomass yields that were 21–26% lower than the inorganic fertigation control. However, fertigation with chicken manure extract, or a combination of fertilizer derived from acidic extraction and N-enriched water, resulted in similar plant growth as inorganic fertilizer. The lower yield from fertilizer derived from acidic extraction was due to elevated EC levels in the growing medium. Our results suggest that yield of greenhouse-grown parsley using either organic fertilizers combined with N-enriched water or chicken manure extract is similar to conventional fertilizer.

The distribution of bloom-forming cyanobacteria in eutrophic to hypereutrophic ponds was studied in northern Taiwan in 2009. Eighty-four ponds were sampled in mid-summer, and the relationship between colony size and relative abundance of each cyanobacterial species was analyzed. Anabaena crassa and Cylindrospermopsis raciborskii were the dominant species in terms of frequency of appearance. The colony size of An. crassa increased significantly with its relative abundance. The relative abundance of C. raciborskii was usually below 10%, and its filament length was not correlated with its relative abundance. The colonies of Microcystis aeruginosa normally consisted of several tens of cells. However, when M. aeruginosa exclusively dominated the plankton community, the average number of cells in a colony reached several hundreds. The mean filament length of Planktothricoides raciborskii significantly increased with its relative abundance. The correlations between colony size and relative abundance of the ten cyanobacterial species were significantly positive for three species, insignificantly positive for five species and insignificantly negative for two species. Given the various ecological advantages of large colonies, the results of this study may suggest that the formation of large colonies of some cyanobacterial species is important to their dominance and/or bloom formation.

Carbon and nitrogen contents of two intertidal fucoid species, Fucus serratus and Himanthalia elongata, were investigated with respect to variations in seasonal resource availability, growth and reproductive requirements. The linear growth rate of F. serratus peaked in spring at 2·3 cm 28 d−1, compared with <0·1 cm 28 d−1 in the winter. In H. elongata, the button diameter increased slowly throughout the year (<0·22 cm 28 d−1) ; in contrast, the receptacle had an elongation rate of up to 7·8 cm 28 d−1 in the spring months. There was no difference in the nitrogen content (% dry weight, dwt) of the vegetative tissue of both non-reproductive and fertile thalli and receptacle tissue of F. serratus, but the nitrogen content of all three tissue types varied seasonally. Reproductive development was initiated in May when nitrogen content was at its peak (3 % dwt). Tissue nitrogen content decreased rapidly through reproductive development to a minimum of less than 1·5% dwt in August; this decrease also occurred in non-reproductive thalli. Tissue nitrogen varied between 0·5 and 1·75% dwt in the vegetative buttons on both non-reproductive and fertile H. elongata, but not in a distinct seasonal manner. Receptacle development in H. elongata was initiated in October/November. The nitrogen content of the receptacle tissue increased rapidly in the first two months of reproductive development (up to 2·5% dwt) then progressively decreased throughout the remaining period of reproductive development. There was no evidence of carbon storage in the vegetative tissues of either F. serratus or H. elongata.