Can an agricultural 'commodity' be de-commodified, and if so who is to gain?

The weakness of redistributional mechanisms, both globally and within developing economies, makes it imperative to directly enhance the productive incomes of poor people. Coffee farmers, generally located in the poorest countries, have suffered especially badly in recent years, and farm gate and internationally traded bean prices are now at historically low levels. At the same time, though, global coffee consumers are becoming more discerning. With at least as much potential taste variety as in the case of wine, final product prices are becoming more differentiated. Margins for some coffees can therefore be expected to increase significantly as consumers become more discriminating in their tastes. But who is to gain from these more differentiated prices? Analysis shows that whilst the price spread is growing in global trading markets, it is simultaneously narrowing at the farm gate. At the same time, the destruction of coffee marketing boards (largely as a result of Structural Adjustment Programmes) has had unintended effects: instead of their margins accruing to farmers, almost all of these margins are being absorbed in the high-income importing countries. Thus, left to market forces, the likelihood is that farmers will gain little from increasingly discriminating final consumer tastes. Instead it is the global branders and the supermarket chains who are likely to appropriate these growing product rents. However, if consumers can be educated to recognise that better coffees are directly linked to their place of origin rather than to their brand names, a more equal global distribution of income is likely to emerge in this value chain. This paper ends with a discussion of which stakeholders may be involved in educating final consumer tastes in an appropriate manner

Root system architecture determines fitness in an Arabidopsis mutant in competition for immobile phosphate ions but not for nitrate ions

Plant root systems often have complex branching patterns. Models indicate that a complex architecture is only required for the acquisition of immobile resources, such as phosphate; mobile ions, notably nitrate, can be effectively taken up by very restricted root systems. We have tested this prediction using the axr4 mutation of Arabidopsis thaliana, the principal phenotypic effect of which is to reduce the number of lateral roots. Arabidopsis thaliana is not a host for mycorrhizal fungi and so acquires all its nutrients through the root system. In both a pot experiment and a field experiment conducted under natural conditions for A. thaliana, we found that only phosphate, and not nitrate, affected the fitness of the mutant relative to the isogenic wild-type line, Columbia. These results confirm model predictions and have implications both for the evolution of complex root systems and for the design of efficient root systems for crops

Phosphorus nutrition of ectomycorrhizal and arbuscular mycorrhizal tree seedlings from a lowland tropical rain forest in Korup National Park, Cameroon

The relationship between mycorrhizal colonisation and phosphorus acquired by seedlings of the arbuscular mycorrhizal tree Oubanguia alata Bak f. (Scytopetalaceae) and the ectomycorrhizal tree Tetraberlinia moreliana Aubr. (Caesalpiniodeae) was evaluated at low and high inorganic phosphorus availability. AM colonisation was positively correlated with phosphorus uptake by O. alata at low, but not at high phosphorus availability. Seedlings growth was positively related to arbuscular mycorrhizal colonisation at both low and high phosphorus availability, suggesting that growth promotion by arbuscular mycorrhizas is not simply related to an increase of phosphorus uptake. In contrast, phosphorus uptake by T. moreliana was correlated with EM colonisation at both low and high phosphorus availability, but there was no relationship between growth and ectomycorrhizal colonisation. Promotion of phosphorus uptake by arbuscular mycorrhizas and ectomycorrhizas at low phosphorus availability is consistent with the co-occurrence of the two types of mycorrhiza in tropical rain forests where available soil phosphorus is low. However, ectomycorrhizal colonisation may also be of advantage where inputs of phosphorus rich litter raise the phosphorus status of the soil, as seen in the groves of ectomycorrhizal trees in Korup National Park, and may be one of the factors reinforcing local dominance by these trees

Ribosomal small subunit sequence diversity of Scutellospora within single spores and roots of bluebell from a woodland community.

Roots of bluebell (Hyacinthoides nonscripta) were sampled from a woodland in Yorkshire,UK and spores of an arbuscular mycorrhizal fungus Scutellospora sp., were obtained from the surrounding soil. Partial small subunit (SSU) ribosomal RNA sequences were amplified from both roots and spores using either the universal forward primer SS38 or the Glomales-specific primer VANS1, with the reverse Gigasporaceaespecific primer VAGIGA. Amplified products were cloned and sequenced. Both spores and roots yielded sequences related to those known from fungi within the Glomales,with up to four distinct SSU sequences obtained from individual spores. The VANS1 primer-binding site varied considerably in sequence and only a subset of Scutellospora sequences were amplified when the VANS1 primer was used. In addition to glomalean sequences, a number of different sequences, apparently from ascomycetes, were obtained from both root and spore samples

An arbuscular mycorrhizal fungus accelerates decomposition and acquires nitrogen directly from organic material

Arbuscular mycorrhizal fungi (order Glomales), which form mycorrhizal symbioses with two out of three of all plant species, are believed to be obligate biotrophs that are wholly dependent on the plant partner for their carbon supply. It is thought that they possess no degradative capability and that they are unable to decompose complex organic molecules, the form in which most soil nutrients occur. Earlier suggestions that they could exist saprotrophically were based on observation of hyphal proliferation on organic materials. In contrast, other mycorrhizal types have been shown to acquire nitrogen directly from organic sources. Here we show that the arbuscular mycorrhizal symbiosis can both enhance decomposition of and increase nitrogen capture from complex organic material (grass leaves) in soil. Hyphal growth of the fungal partner was increased in the presence of the organic material, independently of the host plant

Strawberry Detection Under Various Harvestation Stages

This paper analyzes three techniques attempting to detect strawberries at various stages in its growth cycle. Histogram of Oriented Gradients (HOG), Local Binary Patterns (LBP) and Convolutional Neural Networks (CNN) were implemented on a limited custom-built dataset. The methodologies were compared in terms of accuracy and computational efficiency. Computational efficiency is defined in terms of image resolution as testing on a smaller dimensional image is much quicker than larger dimensions. The CNN based implementation obtained the best results with an 88% accuracy at the highest level of efficiency as well (600x800). LBP generated moderate results with a 74% detection accuracy at an inefficient rate (5000x4000). Finally, HOG’s results were inconclusive as it performed poorly early on, generating too many misclassifications

Plant root proliferation in nitrogen-rich patches confers competitive advantage

Plants respond to environmental heterogeneity, particularly below ground, where spectacular root proliferations in nutrient-rich patches may occur. Such 'foraging' responses apparently maximize nutrient uptake and are now prominent in plant ecological theory. Proliferations in nitrogen-rich patches are difficult to explain adaptively, however. The high mobility of soil nitrate should limit the contribution of proliferation to N capture. Many experiments on isolated plants show only a weak relation between proliferation and N uptake. We show that N capture is associated strongly with proliferation during interspecific competition for finite, locally available, mixed N sources, precisely the conditions under which N becomes available to plants on generally infertile soils. This explains why N-induced root proliferation is an important resource-capture mechanism in N-limited plant communities and suggests that increasing proliferation by crop breeding or genetic manipulation will have a limited impact on N capture by well-fertilized monocultures

Resource and non-resource root competition among trees of different successional status

1. This study assessed the effects of resource (i.e. nutrients) and non-resource (i.e. interference for space) competition from fine roots of competing grasses on the growth, morphology and architecture of fine roots of four tree species of varying successional status: Populus deltoides × P. balsamifera (a\ud hybrid), Betula papyrifera, Acer saccharum and Fraxinus americana. We tested the general hypothesis that tree fine-roots are affected by both below-ground resource and non-resource competition from non-self plants, and the more specific hypothesis that this effect is stronger in early- successional tree species.\ud 2. The experiment was conducted in split-containers where half of the roots of tree seedlings experienced either below-ground resource competition or non-resource competition, or both, by grasses while the other half experienced no competition.\ud 3. The late-successional tree species A. saccharum and\ud F. americana were mostly affected by resource competition, whereas the early-successional P. deltoides × balsamifera\ud and B. papyrifera were strongly affected by both resource and non-resource competition. Non-resource competition reduced fine-root growth, root branching over root length (a measure of root architecture) and specific root length (a measure of root morphology) of both early-successional species.\ud 4. Synthesis. This study suggests that early-successional tree species have been selected for root avoidance or segregation and late-successional tree species for root tolerance of competition as mechanisms to improve below-ground resource uptake in their particular environments. It also\ud contradicts recent studies showing perennial and annual grasses tend to overproduce roots in the presence of non-self conspecific plants. Woody plants, required to grow and develop for long periods in the presence of other plants, may react differently to non-self root competition than perennial or\ud annual grasses that have much shorter lives