A comparison of the role of two blue-green algae in THM and HAA formation

The contribution of two blue-green algae species, Anabaeria flos-aquae and Microcystis aeruginosa, to the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) was investigated. The experiments examined the formation potential of these disinfection by-products (DBPs) from both algae cells and extracellular organic matter (EOM) during four algal growth phases. Algal cells and EOM of Anabaena and Microcystis exhibited a high potential for DBP formation. Yields of total THMs (TTHM) and total HAAs (THAA) were closely related to the growth phase. Reactivity of EOM from Anabaena was slightly higher than corresponding cells, while the opposite result was found for Microcystis. Specific DBP yields (yield/unit C) of Anabaena were in the range of 2-11 mu mol/mmol C for TTHM and 217 mu mol/mmol C for THAA, while those of Microcystis were slightly higher. With regard to the distributions of individual THM and HAA compounds, differences were observed between the algae species and also between cells and EOM. The presence of bromide shifted the dominant compounds from HAAs to THMs. (C) 2009 Elsevier Ltd. All rights reserved.

The impact of fallowing and green manuring on soil conditions and the growth of sugarcane

There are currently concerns within some sugar industries that long-term monoculture has led to soil degradation and consequent yield decline. An investigation was conducted in Swaziland to assess the effects of fallowing and green manuring practices, over a seven-month period, on sugarcane yields and the physical properties of a poorly draining clay soil. In the subsequent first sugarcane crop after planting, yields were improved from 129 t ha(-1) under continuous sugarcane to 141-144 t ha(-1) after fallowing and green manuring, but there were no significant responses in the first and second ratoon crops. Also, in the first crop after planting, root length index increased from 3.5 km m(-2) under continuous sugarcane to 5.2-6.8 km m(-2) after fallowing, and improved rooting was still evident in the first ratoon crop where there had been soil drying during the fallow period. Soil bulk density, total porosity and water-holding capacity were not affected by the fallowing practices. However, air-filled porosity increased from 11% under continuous sugarcane to 16% after fallowing, and steady state ponded infiltration rates were increased from 0.61 mm h(-1) to 1.34 mm h(-1), but these improvements were no longer evident after a year back under sugarcane. Levels of soil organic matter were reduced in all cases, probably as a result of the tillage operations involved. In the plant crop, root length was well correlated with air-filled porosity, indicating the importance of improving belowground air supply for crop production on poorly draining clay soils.

Presubmergence and green manure affect the transformations of nitrogen-15-labeled urea under lowland soil conditions

The effect of presubmergence and green manuring on various processes involved in [N-15]-urea transformations were studied in a growth chamber after [N-15]-urea application to floodwater. Presubmergence for 14 days increased urea hydrolysis rates and floodwater pH, resulting in higher NH3 volatilization as compared to without presubmergence. Presubmergence also increased nitrification and subsequent denitrification but lower N assimilation by floodwater algae caused higher gaseous losses. Addition of green manure maintained higher NH4+-N concentration in floodwater mainly because of lower nitrification rates but resulted in highest NH3 volatilization losses. Although green manure did not affect the KCl extractable NH4+-N from applied fertilizer, it maintained higher NH4+-N content due to its decomposition and increased mineralization of organic N. After 32 days about 36.9% (T-1), 23.9% (T-2), and 36.4% (T-3) of the applied urea N was incorporated in the pool of soil organic N in treatments. It was evident that the presubmergence has effected the recovery of applied urea N.

The diurnal cycle of convection and atmospheric tides in an aquaplanet

The diurnal cycle of tropical convection and its relationship to the atmospheric tides is investigated using an aquaplanet GCM. The diurnal and semidiurnal harmonics of precipitation are both found to contribute significantly to the total diurnal variability of precipitation in the model, which is broadly consistent with observations of the diurnal cycle of convection over the open ocean. The semidiurnal tide is found to be the dominant forcing for the semidiurnal harmonic of precipitation. In contrast the diurnal tide plays only a small role in forcing the diurnal harmonic of precipitation, which is dominated by the variations in shortwave and longwave heating. In both the diurnal and semidiurnal harmonics, the feedback onto the convection by the humidity tendencies due to the convection is found to be important in determining the phase of the harmonics. Further experiments show that the diurnal cycle of precipitation is sensitive to the choice of closure in the convection scheme. While the surface pressure signal of the simulated atmospheric tides in the model agree well with both theory and observations in their magnitude and phase, sensitivity experiments suggest that the role of the stratospheric ozone in forcing the semidiurnal tide is much reduced compared to theoretical predictions. Furthermore, the influence of the cloud radiative effects seems small. It is suggested that the radiative heating profile in the troposphere, associated primarily with the water vapor distribution, is more important than previously thought for driving the semidiurnal tide. However, this result may be sensitive to the vertical resolution and extent of the model.

Implications of Commons Act 2006 for the registration of land as a town or village green

This paper describes the main changes of Commons Act 2006 for the registration of land as a town or village green. The purpose of the Commons Act 2006 is to protect common land and promote sustainable farming, public access to the countryside and the interests of wildlife. The changes under s15 of the Commons Act 2006 include the additional 2-year grace period for application, discounting statutory period of closure, correction of mistakes in registers, disallowing severance of rights, voluntary registration, replacement of land in exchange and some other provisions. The transitional provision contained in s15(4) Commons Act 2006 is particularly a cause for controversy as DEFRA has indicated buildings will have to be taken down where development has gone ahead and a subsequent application to register the land as a green is successful, obliging the developer to return the land to a condition consistent with the exercise by locals of recreational rights, which sums up that it would be harder in future to develop land which has the potential to be registered as a town or village green.

Participatory Farm Management methods for assessing the suitability of potential innovations. A case study on green manuring options for tomato producers in Ghana

This paper examines the potential of using Participatory Farm Management methods to examine the suitability of a technology with farmers prior to on-farm trials. A study examining the suitability of green manuring as a technology for use with wet season tomato producers in Ghana is described. Findings from this case-study demonstrate that Participatory Budgeting can be used by farmers and researchers to analyse current cultivation practices, identify the options for including green manures into the system and explore the direct and wider resource implications of the technology. Scored-Causal Diagrams can be used to identify farmers' perceptions of the relative importance of the problem that the technology seeks to address. The use of the methods in this examine evaluation process appears to have the potential to improve the effectiveness and efficiency of the adaptive research process. This ensures that technologies subsequently examined in trials ate relevant to farmers' interests, existing systems and resources, thereby increasing the chances of farmer adoption. It is concluded that this process has potential for use-with other technologies and in other farming systems. (C) 2002 Elsevier Science Ltd. All rights reserved.

Decoupling EU farm support: Does the new single payment scheme fit within the green box?

Recent reform of the EU’s Common Agricultural Policy (CAP) has led to a further decoupling of farm support. The EU believes that the new Single Payment Scheme, which replaces the former system of area and headage payments to farmers, tied to production, will qualify for green-box status in the WTO. We examine this contention, particularly in light of the recent WTO panel report on upland cotton.

Antioxidant activity and protective effects of green and dark coffee components against human low density lipoprotein oxidation

The in vitro antioxidant activity and the protective effect against human low density lipoprotein oxidation of coffees prepared using different degrees of roasting was evaluated. Coffees with the highest amount of brown pigments (dark coffee) showed the highest peroxyl radical scavenging activity. These coffees also protected human low-density lipoprotein (LDL) against oxidation, although green coffee extracts showed more protection. In a different experiment, coffee extracts were incubated with human plasma prior to isolation of LDL particles. This showed, for the first time, that incubation of plasma with dark, but not green coffee extracts protected the LDL against oxidation by copper or by the thermolabile azo compound AAPH. Antioxidants in the dark coffee extracts must therefore have become associated with the LDL particles. Brown compounds, especially those derived from the Maillard reaction, are the compounds most likely to be responsible for this activity.

Aphidius ervi preferentially attacks the green morph of the pea aphid, Acyrthosiphon pisum

The pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae) is found in red and green color morphs. Previous work has suggested that the aphidiine parasitoid Aphidius ervi Haliday preferentially attacks green pea aphids in the field. It is not clear whether these results reflect a real preference, or some unknown clonal difference, such as in immunity, between the aphids used in the previous studies. We used three susceptibility-matched pairs of red and green morph pea aphid clones to test for preferences. In a no-choice situation, the parasitoids attacked equal proportions of each color morph. When provided with a choice, A. ervi was significantly more likely to oviposit into colonies formed from green morphs when the neighboring colony was formed from red morph aphids. In contrast, red morphs were less likely to be attacked when their neighboring colony was of the green morph. By preferentially attacking green colonies, A. ervi may reduce the likelihood of intraguild predation, as it is suggested that visually foraging predators preferentially attack red aphid colonies. Furthermore, if this host choice behavior is replicated in the field, we speculate that color morphs of the pea aphid may interact indirectly through their shared natural enemies, leading to intraspecific apparent competition.