The influence of biostimulants on growth and vitality of three urban tree species following transplanting

Four commercially available, biostimulants sold under the trade names ‘Generate’, ‘Crop Set’, ‘Fulcrum’ and ‘Redicrop 2000’ were applied either as a root drench or foliar spray to three transplant-sensitive tree species, red oak(Quercus rubra), birch(Betula pendula) and beech (Fagus sylvatica) post transplanting. The short and long-term efficacy of the biostimulants on growth was quantified by recording root and shoot vigour at week 8 and 20. In addition, improvements in tree vitality were assessed by measurement of a chlorophyll a performance index based on leaf chlorophyll fluorescence emissions. Irrespective of species, no significant effect of mode of application (foliar spray versus root drench) was recorded on growth and vitality. The biostimulants Generate and Fulcrum increased growth of all three tree species. No significant effects on growth and chlorophyll fluorescence of birch and beech were recorded following applications of the biostimulants Crop Set and Redicrop 2000, however, significant increase in growth of red oak was recorded. Only the biostimulant Generate increased chlorophyll fluorescence values of all test species. Results show use of biostimulants can improve root and shoot vigour following transplanting. However, selection of an appropriate biostimulant is critical as effects on growth and vitality can vary widely between tree species possibly as a result of the differing active ingredient used in the formulation of the product.

The influence of markets and policy on spatial patterns of non-timber forest product extraction

When villagers extract resources, such as fuelwood, fodder, or medicinal plants from forests, their decisions over where and how much to extract are influenced by market conditions, their particular opportunity costs of time, minimum consumption needs, and access to markets. This paper develops an optimization model of villagers’ extraction behavior that clarifies how, and under what conditions, policies that create incentives such as improved returns to extraction in a buffer zone might be used instead of adversarial enforcement efforts to protect a forest’s pristine ‘‘inner core.’’

Effects of acid sulphate on DOC release in mineral soils: the influence of SO42−retention and Al release

Dissolved organic carbon (DOC) in acid-sensitive upland waters is dominated by allochthonous inputs from organic-rich soils, yet inter-site variability in soil DOC release to changes in acidity has received scant attention in spite of the reported differences between locations in surface water DOC trends over the last few decades. In a previous paper, we demonstrated that pH-related retention of DOC in O horizon soils was influenced by acid-base status, particularly the exchangeable Al content. In the present paper, we investigate the effect of sulphate additions (0–437 μeq l−1) on DOC release in the mineral B horizon soils from the same locations. Dissolved organic carbon release decreased with declining pH in all soils, although the shape of the pH-DOC relationships differed between locations, reflecting the multiple factors controlling DOC mobility. The release of DOC decreased by 32–91% in the treatment with the largest acid input (437 μeq l−1), with the greatest decreases occurring in soils with very small % base saturation (BS, <3%) and/or large capacity for sulphate (SO42−) retention (up to 35% of added SO42−). The greatest DOC release occurred in the soil with the largest initial base status (12% BS). These results support our earlier conclusions that differences in acid-base status between soils alter the sensitivity of DOC release to similar sulphur deposition declines. However,superimposed on this is the capacity of mineral soils to sorb DOC and SO42−, and more work is needed to determine the fate of sorbed DOC under conditions of increasing pH and decreasing SO42−.

The influence of environmental policy on the decisions of managers to adopt G-SCM practices

This article explores the reasons that affect the decisions of managers of firms to adopt management practices in order to green their supply chain management. Under the context of environmental policy, the relationship between policy instruments (‘command and control’, market-based, and self-regulated) and the decisions of managers to adopt green supply chain management (G-SCM) practices is examined. The results show that in some cases the environmental legislation, market-based instruments and self-regulated incentives could play a critical role in the decisions of managers to adopt some specific G-SCM practices, while in other cases environmental policy instruments have not seemed to affect the decisions of managers regarding some other G-SCM practices.

The influence of shade and organic fertilizer treatments on the physiology and establishment of Theobroma cacao clones

Aims: This experiment aimed to determine whether the soil application of organic fertilizers can help the establishment of cacao and whether shade alters its response to fertilizers. Study Design: The 1.6 ha experiment was conducted over a period of one crop year (between April 2007 and March 2008) at the Cocoa Research Institute of Ghana. It involved four cacao genotypes (T 79/501, PA 150, P 30 [POS] and SCA 6), three shade levels (‘light’, ‘medium’ and ‘heavy’) and two fertilizer treatments (‘no fertilizer’, and ‘140 kg/ha of cacao pod husk ash (CPHA) plus poultry manure at 1,800 kg/ha). The experiment was designed as a split-plot with the cacao genotypes as the main plot factor and shade x fertilizer combinations as the sub-plots. Methodology: Gliricidia sepium and plantains (Musa sapientum) were planted in different arrangements to create the three temporary shade regimes for the cacao. Data were collected on temperature and relative humidity of the shade environments, initial soil nutrients, soil moisture, leaf N, P and K+ contents, survival, photo synthesis and growth of test plants. Results: The genotypes P 30 [POS] and SCA 6 showed lower stomatal conductance under non-limiting conditions. In the rainy seasons, plants under light shade had the highest CO2 assimilation rates. However, in the dry season, plants under increased shade recorded greater photosynthetic rates (P = .03). A significant shade x fertilizer interaction (P = .001) on photosynthesis in the dry season showed that heavier shade increases the benefits that young cacao gets from fertilizer application in that season. Conversely, shade should be reduced during the wet seasons to minimize light limitation to assimilation. Conclusion: Under ideal weather conditions young cacao exhibits genetic variability on stomatal conductance. Also, to optimize plant response to fertilizer application shade must be adjusted taking the prevailing weather condition into account.

The influence of sea ice dynamics on the climate sensitivity and memory to increased Antarctic sea ice

The study analyzes the sensitivity and memory of the Southern Hemisphere coupled climate system to increased Antarctic sea ice (ASI), taking into account the persistence of the sea ice maxima in the current climate. The mechanisms involved in restoring the climate balance under two sets of experiments, which differ in regard to their sea ice models, are discussed. The experiments are perturbed with extremes of ASI and integrated for 10 yr in a large 30-member ensemble. The results show that an ASI maximum is able to persist for ; 4 yr in the current climate, followed by a negative sea ice phase. The sea ice insulating effect during the positive phase reduces heat fluxes south of 60 8 S, while at the same time these are intensified at the sea ice edge. The increased air stability over the sea ice field strengthens the polar cell while the baroclinicity increases at midlatitudes. The mean sea level pressure is reduced (increased) over high latitudes (midlatitudes), typical of the southern annular mode (SAM) positive phase. The Southern Ocean (SO) becomes colder and fresher as the sea ice melts mainly through sea ice lateral melting, the consequence of which is an increase in the ocean stability by buoyancy and mixing changes. The climate sensitivity is triggered by the sea ice insulating process and the resulting freshwater pulse (fast response), while the climate equilibrium is restored by the heat stored in the SO subsurface layers (long response). It is concluded that the time needed for the ASI anomaly to be dissipated and/or melted is shortened by the sea ice dynamical processes.