HPLC fluorometric determination of natural phytoplankton phycocyanin and its usefulness as cyanobacterial biomass in highly eutrophic shallow lake

A method for HPLC determination of phycocyanin in phytoplankton samples using gelchromatography with a fluorescence detector was developed to examine the use of phycocyanin as an index of the appearance and progress of cyanobacterial blooms in highly eutrophic lake. At least two types of phycocyanin with different molecular weights, each spectroscopically different from phycoerythrin and allophycocyanin, were found in natural phytoplankton samples. Changes in phycocyanin concentrations were clearly coupled to changes in chlorophyll-a concentrations during June to October while cyanobacterial blooms were occurring. The chlorophyll-a to phycocyanin relationship was linear at chlorophyll-a concentrations of less than 250 μg L^?1. The relationship between cyanobacterial carbon and phycocyanin concentration was also linear, suggesting that phycocyanin content may be a useful index of cyanobacterial biomass in highly eutrophic lakes where large cyanobacterial blooms occur.     

Toward the development of a weather index insurance for rice farmers in the coastal region of Myanmar

Paddy and Water Environment - Climate change is expected to exacerbate damage to agricultural production from natural disasters. Examination of measures to adapt to the damage represents an urgent...     

Contingent valuation approach in measuring the multifunctionality of agriculture and rural areas in Japan

The purpose of this study was to measure the economic value of the multifunctionality of agriculture and rural areas based on a more realistic assumption than that adopted in previous studies. Willingness to pay (WTP) for implementing a policy that would maintain a level of multifunctionality corresponding to a 20% decrease in the farmland area in Japan was measured by the double-bounded dichotomous choice contingent valuation method (CVM). According to a country-wide survey, the overall median WTP was 4,144 yen per household annually. The multifunctionality of agriculture and rural areas was classified into eight functions. The WTP for each of these functions was calculated taking into account the ratings assigned to the functions by the respondents. The WTP was 649 yen for flood prevention, 505 yen for recharging groundwater, 642 yen for water environment conservation, 445 yen for soil erosion prevention, 579 yen for organic resource utilization, 394 yen for the development of favorable landscapes, 290 yen for recreation and relaxation, and 641 yen for wildlife protection.     

In-crisis delivery rate: a novel measure of success in communal water management

Of the plethora of studies that discuss requirements for successful irrigation management, few pay close attention to what actually happens when the supply of water becomes extremely low. Such an oversight in the literature is unfortunate, because this is precisely when management matters. To understand what separates success from failure in irrigation management at times of critical water shortages, the authors conducted emergency fieldwork in February 2010 along four major irrigation channels in a drought-stricken rice-growing area within the Chinese province of Yunnan. Separately, satellite images of the four villages dated February 2009 and February 2010 were jointly analysed to produce a novel indicator for a village’s success in water management. Called the in-crisis delivery rate, this indicator compares water delivery between normal and drought years and directly evaluates performance in water management during crisis periods. The results led to an unexpected discovery that, contrary to common expectations, the only village of the present study that deployed a traditional earthen water channel secured substantially more water throughout the drought period than those with concrete-lined channels. It is hypothesised that the labour intensive, rather than capital intensive, nature of repair work of the earthen channel enabled flexible operations, and hence had the comparative advantage under a skilled management team. This result confirms the importance of daily maintenance work, which tends to occur less often after modernisation of water paths.     

Measuring farmers’ preferences for weather index insurance in the Ayeyarwady Delta,Myanmar: a discrete choice experiment approach

Paddy and Water Environment - This study examines farmers’ preferences for weather index insurance (WII) in the Ayeyarwady Delta, Myanmar, using discrete choice experiments. It employs data...