Taxonomic shifts in arbuscular mycorrhizal fungal communities with shade and soil nitrogen across conventionally managed and organic coffee agroecosystems

The composition of arbuscular mycorrhizal fungal (AMF) communities should reflect not only responses to host and soil environments, but also differences in functional roles and costs vs. benefits among arbuscular mycorrhizal fungi. The coffee agroecosystem allows exploration of the effects of both light and soil fertility on AMF communities, because of the variation in shade and soil nutrients farmers generate through field management. We used high-throughput ITS2 sequencing to characterize the AMF communities of coffee roots in 25 fields in Costa Rica that ranged from organic management with high shade and no chemical fertilizers to conventionally managed fields with minimal shade and high N fertilization, and examined relationships between AMF communities and soil and shade parameters with partial correlations, NMDS, PERMANOVA, and partial least squares analysis. Gigasporaceae and Acaulosporaceae dominated coffee AMF communities in terms of relative abundance and richness, respectively. Gigasporaceae richness was greatest in conventionally managed fields, while Glomeraceae richness was greatest in organic fields. While total AMF richness and root colonization did not differ between organic and conventionally managed fields, AMF community composition did; these differences were correlated with soil nitrate and shade. OTUs differing in relative abundance between conventionally managed and organic fields segregated into four groups: Gigasporaceae associated with high light and nitrate availability, Acaulosporaceae with high light and low nitrate availability, Acaulosporaceae and a single relative of Rhizophagus fasciculatus with shade and low nitrate availability, and Claroideoglomus/Glomus with conventionally managed fields but uncorrelated with shade and soil variables. The association of closely related taxa with similar shade and light availabilities is consistent with phylogenetic trait conservatism in AM fungi

Effect of Shade and Integrated Nutrient Management on Biochemical Constituents of Turmeric (Curcuma longa L.)

A field experiment was conducted to study the effect of partial shade, inorganic, organic and biofertilizers on biochemical constituents and quality of turmeric. The study was laid out in split plot design, consisting of two main plots viz., open and shade. The sub-plot treatments consisted of different doses of inorganic fertilizers, organic manures, biofertilizers and growth stimulants constituting of 40 different treatment combinations. The treatment combinations, viz., shade with application of 100 % recommended dose of NPK + 50 % FYM (15 t ha-1) + coir compost (10 t ha-1) + Azospirillum (10 kg ha-1) + phosphobacteria (10 kg ha-1) + 3 % panchagavya showed increased total chlorophyll content, total phenol content and registered the highest yield per plot. On the contrary, provision of shade decreased the curing percentage as compared to open condition. Among the quality characters, the highest curcumin (5.57 %) and essential oil (5.68 %) content were registered in the treatment, shade with application of 50 % FYM + coir compost + Azospirillum (10 kg ha-1) + phosphobacteria (10 kg ha-1) + 3 % panchagavya

Managing understory light conditions in boreal mixedwoods through variation in the intensity and spatial pattern of harvest: A modelling approach

In the context of partial harvesting, adequately managing post-harvest light conditions are essential to obtain a desired composition of tree species regeneration. The objective of this study was to determine how varying the intensity and spatial pattern of harvest would affect understory light conditions in boreal mixedwood stands of northwestern Quebec using the spatially explicit SORTIE-ND light model. The model was evaluated based on comparisons of observed and predicted light levels in both mapped and un-mapped plots. In mapped plots, reasonably accurate predictions of the overall variation in light levels were obtained, but predictions tended to lack spatial precision. In un-mapped plots, SORTIE-ND accurately predicted stand-level mean GLI (Gap Light Index) under a range of harvest intensities. The model was then used to simulate nine silvicultural treatments based on combinations of three intensities of overstory removal (30%, 45% and 60% of basal area) and three harvest patterns (uniform, narrow strips, large gaps). Simulations showed that increasing overstory removal had less impact on light conditions with uniform harvests, and a more marked effect with more aggregated harvest patterns. Whatever the harvest intensity, uniform cuts almost never created high light conditions (GLI > 50%). Gap cuts, on the other hand, resulted in up to 40% of microsites receiving GLI > 50%. Our results suggest that either a 30% strip or gap cut or a 45–60% uniform partial harvest could be used to accelerate the transition from an aspen dominated composition to a mixedwood stand because both types of cut generate the greatest proportion of moderately low light levels (e.g., 15–40% GLI). These light levels tend to favour an accelerated growth response among shade-tolerant conifers, while preventing excessive recruitment of shade-intolerant species. A better understanding of how spatial patterns of harvest interact with tree removal intensity to affect understory light conditions can provide opportunities for designing silvicultural prescriptions that are tailored to species’ traits and better suited to meet a variety of management objectives

Social and spatial structure in brook chars (Salvelinus fontinalis) under competition for food and shelter/shade

Salmonids, outside their reproductive period, are seen to have two types of territory called "territorial mosaic" and "partial territory". The first aspect of this research aimed at identifying the type of territory established by mature brook chars in artificial streams. After this, the biological value of spacing out was studied with regard to two resources: food, and shelter/shade which gives protection. Three 5 X 1 X 1 m artificial streams were built on the edge of a natural brook which provided a continuous water supply. One hundred and fifty mature brook chars (Salvelinus fontinalis) taken from that brook were distributed into 30 colonies with 5 members apiece. Three experimental conditions were created, and 10 colonies were submitted to each of these. In the first experimental condition, the quality of shelter/shade differed in 3 sectors of the artificial streams, whereas the quantity of food remained the same for all 3. In the second experimental condition, the quality of shelter/shade was identical, while the quantity of food differed in the 3 sectors. In the last condition, conflict was created: the fish had to choose between an area which offered excellent shelter/shade but no food, one which provided ample nourishment but no shelter/shade, and one in which all those resources were present at intermediate levels. Observation of the 30 colonies revealed "partial territory" in all cases. These corresponded to more or less complete aggressive-dominance hierarchies. Almost every alpha established territory, and the number of territorial individuals progressively decreased throughout inferior ranks. Alphas had exclusive use of their territory. Lower-ranking individuals successfully defended their territory against their subordinates, but were unable to drive away higher-ranking conspecifics. Overall results also indicated that the highest-ranking brook chars in the aggressive-dominance hierarchies more frequently established their territories in sectors of the streams with good shelter/shade than in sectors with good alimentary conditions

Socio-Economic Impact of a Cocoa Integrated Crop and Pest Management Diffusion Knowledge Through a Farmer Field School Approach in Southern Cameroon

We focused on the Socio-Economic Evaluation of Farmer Field School Training on Integrated Pest Management in the humid forest region of Cameroon. The main objective was to assess the impact of training on integrated pest management (IPM) on cocoa farmer field school graduates. The results indicate that shade management, phytosanitary harvest, pruning, improved spraying practices and grafting of improved materials were adopted at the rate of 94, 93, 90, 66 and 35 % respectively, with the overall rate of adoption being 76 %. There was a 47 % reduction in the frequency of spraying fungicides and a 17 % reduction in the number of sprayers applied per treatment following the implementation of the training. Labour inputs increased significantly for pruning, phytosanitary harvest, and shade management but decreased for spraying. A partial budget analysis reveals that the IPM practices lowered overall costs of production by 11 % relative to previous practices. The poster presenting the synthesis of this work comprises a general introduction, a methodology and study area map, results and discussion which comprise two photographs of farmer field school activities, a graph and a table of different technical results, a short conclusion and recommendation.integrated pest management, farmer field school, adoption rate, Crop Production/Industries,

Functional ecology of advance regeneration in relation to light in boreal forests

This paper reviews aspects of the functional ecology of naturally established tree seedlings in the boreal forests of North America with an emphasis on the relationship between light availability and the growth and survival of shade tolerant conifers up to pole size. Shade tolerant conifer species such as firs and spruces tend to have a lower specific leaf mass, photosynthetic rate at saturation, live crown ratio, STAR (shoot silhouette area to total needle surface area ratio), and root to shoot ratio than the shade intolerant pines. The inability of intolerant species such as the pines and aspen to survive in shade appears to be mainly the result of characteristics at the shoot, crown, and whole-tree levels and not at the leaf level. Although firs and spruces frequently coexist in shaded understories, they do not have identical growth patterns and crown architectures. We propose a simple framework based on the maximum height that different tree species can sustain in shade, which may help managers determine the timing of partial or complete harvests. Consideration of these functional aspects of regeneration is important to the understanding of boreal forest dynamics and can be useful to forest managers seeking to develop or assess novel silvicultural systems

GROWTH AND SURVIVAL OF PIONEER AND LATE SUCCESSIONAL SPECIES IN SIMULATED LIGHT ENVIRONMENTS IN A SRI LANKAN LOWLAND RAIN FOREST

Growth and survival of two pioneer and four late successional species in different light levels inshade houses were investigated over a period of one year from January 2000 to January 200 1 atthe Sinharaja field research station.Schumacheria castaneifo/ia (Dilleniaceae) and Vltex altissima (Verbenaceae) represented thepioneer species. Psychotria nigra, Gaertnera vaginans (Rubiaceae), Syzygium operculatum andS. rubicundum and (Myrtaceae) were selected as late successional species. The four latesuccessional species were further subdivided into two canopy species (S. operculatum and S.rubicundum) and two understorey species (Psychotria nigra and Gaertnera vaginans) based onheight at maturity oftheir parent trees. Seedlings were grown under four light environments (fullsun, 1200; partial sun, 800; partial shade, 350; shade, 50j.Lmolm-2s-1) that represented a range ofPPFD (photosynthetic photon flux density) found within the forest. Five seedlings of eachspecies were grown in each light environment, which was replicated three times. At the end ofone year the height increments and percentage survival of seedlings were measured.The study revealed that two Syzygium species, Gaertnera vaginans and S. castaneifolia showingthe lowest height increments 'when grown in shade. But no significant difference was observedbetween shade and full sun for these species. Although the lowest height increments for Valtissima and P. nigra were observed in full sun and in partial shade respectively, there is nosignificant difference among shade, partial sun and full sun for V altissima. Psychotria nigra didnot show any significant difference among four light treatments. The greatest relative heightgrowth was observed in partial shade for G. vag/nans and S. castaneifoliz; V altissima, and inpartial sun for two Syzygium species. Plasticity (ratio between highest and lowest values amonglight treatments) measurement of height increment was highest in G. vaginans (3.47), the lowestin P. nigra (l.52) compared to s. operculatum (1.79), S rubicundum (2.18), V altissima (2.19),S. castaneifolia (3.08). Percentage seedling survival of S. castaneifolia, and V a/tissima was100% under all light levels .All species survived equally well in partial sun light level. In shade,seedling survival of G. vaginans, and S operculatum was 93% and in Psychotria nigra, it was80%. G. vaginans and P. nigra showed 93% seedling survival in partial shade .In full sun G.vaginans and S. rubicundum exhibited 93.3% survival while P nigra showed 67 % survival.These results suggest that pioneer species grow and survive well in all light levels than latesuccessional species in early stage of their life cycle.

Shade increases cereal production in mediterranean conditions facing the climate change

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The bryoflora of Fernando de Noronha, Brasil

Twenty-two species of bryophytes are reported from Fernando de Noronha. One of these, Fissidens veracruzensis Pursell, has not been reported previously from Brasil