Open Access Method Article
The total number of co-occurring species (“true species richness”) and the way their respective abundances are distributed (“species abundance distribution”) are two major descriptive traits of species assemblages, in numerical terms. Moreover, beyond mere description, the species abundance distribution may help to infer how ecological factors/constraints are currently shaping the hierarchical structure of species assemblages and thereby, may contribute to shed light upon general traits regarding the functional organisation within communities of species. Unfortunately, both total species richness and exhaustive abundance distributions are not available when dealing with more or less incomplete species inventories, a situation which becomes increasingly frequent with the generalisation of the so-called “quick surveys” and “rapid biodiversity assessments”, which are almost unavoidable when addressing very species-rich assemblages, such as, for example, invertebrate communities. Hence, the necessity of extrapolating with minimum bias (i) the species accumulation curve, thereby deriving reliable estimates of the total species richness of sampled assemblage and (ii) the species abundance distribution to get an exhaustive pattern including the full set of co-occurring species. Previous reports from the same author already dealt with the least-biased extrapolation of species accumulation and the associated derivation of total species richness. Now, an appropriate method is proposed, hereafter, to extrapolate with minimum bias the Species Abundance Distribution itself, when having to deal with only partial species inventories. The method shares in part some theoretical results that had already served to support the extrapolation of species accumulation process. The procedure leading to the extrapolation of the Species Abundance Distribution is first detailed in principle and then put into practice utilising a few examples. Improvements as compared to an earlier attempt at the same goal are discussed.
Open Access Short Research Article
The common octopus (Octopus vulgaris) has aroused great interest in recent years as a new species for aquaculture. The current research is focused on developing a formulated feed, although a proper diet management has also promoted rearing success of other commercial cultured species. It is documented that wild animals eat depending on prey availability and most experience fasting in nature. Hence, O. vulgaris subadults were subjected to two different feeding schemes, with a similar semi-moist diet, including either 2 (2FDb, control) or 3 (3FDb) non-consecutive days of fasting per week. Growth, feed efficiency (FE), digestibility and condition were assessed after 56 days of rearing. Both feeding schemes promoted similar growth and digestibility (P>0.05), 100% of survival and higher food-intake after fasting. Interestingly, feed efficiency (FE) was enhanced with the 3 fasting days scheme (58.6% vs. 48.3% for 2FDb scheme; P<0.05). Results might indicate that O. vulgaris has the ability to compensate fasting days through an increase in food intake on the subsequent day or a better use of its reserves. Moreover, a reduction on feeding days might promote a decrease in production costs at commercial scale.
Open Access Original Research Article
Siali leaf-plate production is an indispensable means of livelihood in Kandhamal district of Odisha. The leaf has so many uses like plates, bowls and packing material. In the market, it is more precious and advantageous than the Sal leaf due to its low cost, large in size, hygienic, non-odorous, non-toxic, lightweight, heat resistant and biodegradable. The present study was carried out in Kandhamal district putting particular emphasis on two blocks Daringbadi and Raikia. A total of five villages were selected, from which 78 households were randomly chosen. From each block, 7 traders were chosen purposefully and were interviewed. The analytical techniques viz. Descriptive analysis, SWOT analysis, Price spread analysis and value chain analyses were used for the study. The marginalised poor tribal of the district are unaware of the new value stream approach and the road ahead in front of them to commercialise their product. The paper aims at contributing improved livelihoods through a conceptualised value chain incorporating various improved technology, cooperatives and producer organisation. The tribal women perform a variety of functions at different stages in the value chains, but their roles tend to be improper and inadequately acknowledged because they are operating in the informal sector, so this problem should be solved through the intervening solution proposed.
Open Access Original Research Article
Declining soil fertility in sub-Saharan Africa caused by continuous cropping without nutrient inputs has resulted in declining crop yield. The study was aimed to determine the effects of crop rotation and crop residue management on soil pH, organic carbon, nitrogen and available soil P. A split plot experimental design was set up with crop management system (maize monocropping and maize –bean rotation) as main plots and crop residue (maize stover) as sub plots, in three consecutive cropping seasons. At planting, all plots received 60 kg of P2O5/ha and 60 kg of K2O/ha. Results for the three cropping seasons indicated slight decrease in soil acidity, (5.42±.11), increase in soil organic carbon (2.39±.40) and soil total nitrogen from the initial value of 0.15% to 0.22±.03 due to legume rotation. Available soil P improved from 2.99 to 8.65±1.63 cmol kg-1showing significant differences (P≤0.05) under rotation system plus addition of crop residue. Rotation of maize and legumes with crop residue addition is recommended for farmers, which will benefit them in improving soil fertility.
Open Access Original Research Article
A field experiment was conducted to study the integrated nutrient management on growth components of soybean, resource use efficiency and economics of cotton and soybean intercropping system. The study was conducted at All India Coordinated Research Project on soybean, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad, Karnataka (India) during Kharif 2015 and 2016. The experiment was laid out in a randomised complete block design with three replications and twenty treatments. As per the treatments, the organic manure (FYM) and green leaf manures (gliricidia and pongamia) were applied 15 days before sowing of the crop. Vermicompost was spot applied to soil before dibbling of seeds in cotton and soybean intercropping system in 1:2 row proportion, soybean introduced as intercrop in cotton with row spacing of cotton 120 cm and soybean 30 cm. Results of the study indicated that significantly higher soybean growth attributes were observed in sole soybean than intercropped soybean, except for plant height. Among the intercropping system, T3 (150% recommended dose of fertilizer for cotton and soybean) recorded significantly higher number of branches per plant, leaf area per plant, leaf area index, dry matter production and the total number of nodules per plant. Intercropping of cotton and soybean resulted in more efficient utilization of resource. Among the intercropping system, T3 (150% recommended dose of fertilizer for cotton and soybean) recorded higher biomass and leaf area of cotton and soybean intercropping system. Among the different treatments, significantly higher gross returns and net returns were recorded in T3 (150% recommended dose of fertilizer for cotton and soybean) and it was on par with T2 (125% recommended dose of fertilizer for cotton and soybean) and T17 (T1 + Vermicompost 1.25 t ha-1 + Gliricidia 2.5 t ha-1) during both years and in pooled data. Among the different treatments, significantly higher benefit cost ratio was recorded in T16 (T1 + Gliricidia 2.5 t ha-1 + Pongamia 2.5 t ha-1) compared to rest of the intercropping systems and sole cotton and soybean during both years and in pooled data. However, T16 was on par with T2 (125% recommended dose of fertilizer for cotton and soybean) during 2015-16. Farmers can adopt a fertilizer dose of 125: 62.5: 62.5 N, P2O and K2O kg ha-1 in cotton and soybean intercropping system or 100: 50: 50 N, P2O5 and K2O kg ha-1 along with Gliricidia + Pongamia 2.5 t ha-1 each for cotton and soybean intercropping for profitable yields in rainfed situation.