Different composition of plant residues as a driver of microbial community structure and soil organic matter composition: a microcosm study.

Soil organic matter (SOM) is the main pathway of carbon (C) input to the soil with the decomposition of shoot residues, roots and their exudates. The objective was to evaluate the contribution of different vegetal composition and plant parts of Caatinga species and the effects of introducing a grass in the soil microbial community structure and biochemical composition of SOM. A trial was conducted under controlled conditions (120 days) using, separately, the shoot and roots residues of native species from the herbaceous (HERB) and shrub-arboreal (ARB) strata and a grass (GRASS). Megathyrsus maximum, which is native from Africa, but well adapted to the semi-arid conditions of Brazil, was used. Combinations of these species in different proportions were also evaluated: (i) 55 % shrub and trees + 45 % grass (MIX1) and (ii) 75 % shrub and trees + 25 % grass (MIX2). At the end of incubation, soil samples were collected to evaluate the microbial community structure through the phospholipid fatty acids (PLFA). Physical fractioning of SOM into particulate organic matter (POM) and mineralassociated organic matter (MAOM) was also performed, followed by biochemical characterization of these fractions by thermochemolysis analysis. The ARB shoot residue resulted in a 181.5 % increase (p < 0.05) in total PLFA biomass in the soil. A significant increase (p < 0.05) in the abundance of fungi and bacteria was observed with the incorporation of shoot residues. MAOM was characterized by a higher abundance of aliphatic (31.6 ± 5.0 %) and nitrogen-bearing compounds (21.0 ± 2.0 %), while higher lignin derivatives were observed in POM (18.0 ± 0.6 %). The ground cover provided a diversity of compounds in the SOM, thus regulating the structure of the microbial community. These results highlight the importance of conserving biodiversity, both in natural ecosystems and in agroecosystems in the semi-arid environment

Equitability revisited: why the “equitable threat score” is not equitable

In the forecasting of binary events, verification measures that are “equitable” were defined by Gandin and Murphy to satisfy two requirements: 1) they award all random forecasting systems, including those that always issue the same forecast, the same expected score (typically zero), and 2) they are expressible as the linear weighted sum of the elements of the contingency table, where the weights are independent of the entries in the table, apart from the base rate. The authors demonstrate that the widely used “equitable threat score” (ETS), as well as numerous others, satisfies neither of these requirements and only satisfies the first requirement in the limit of an infinite sample size. Such measures are referred to as “asymptotically equitable.” In the case of ETS, the expected score of a random forecasting system is always positive and only falls below 0.01 when the number of samples is greater than around 30. Two other asymptotically equitable measures are the odds ratio skill score and the symmetric extreme dependency score, which are more strongly inequitable than ETS, particularly for rare events; for example, when the base rate is 2% and the sample size is 1000, random but unbiased forecasting systems yield an expected score of around −0.5, reducing in magnitude to −0.01 or smaller only for sample sizes exceeding 25 000. This presents a problem since these nonlinear measures have other desirable properties, in particular being reliable indicators of skill for rare events (provided that the sample size is large enough). A potential way to reconcile these properties with equitability is to recognize that Gandin and Murphy’s two requirements are independent, and the second can be safely discarded without losing the key advantages of equitability that are embodied in the first. This enables inequitable and asymptotically equitable measures to be scaled to make them equitable, while retaining their nonlinearity and other properties such as being reliable indicators of skill for rare events. It also opens up the possibility of designing new equitable verification measures

Soil water dynamics and evapotranspiration of forage cactus clones under rainfed conditions.

The objective of this work was to evaluate soil water dynamics in areas cultivated with forage cactus clones and to determine how environmental conditions and crop growth affect evapotranspiration. The study was conducted in the municipality of Serra Talhada, in the state of Pernambuco, Brazil. Crop growth was monitored through changes in the cladode area index (CAI) and through the soil cover fraction, calculated at the end of the cycle. Real evapotranspiration (ET) of the three evaluated clones was obtained as the residual term in the soil water balance method. No difference was observed between soil water balance components, even though the evaluated clones were of different genus and had different CAI increments. Accumulated ET was of 1,173 mm during the 499 days of the experiment, resulting in daily average of 2.35 mm. The CAI increases the water consumption of the Orelha de Elefante Mexicana clone. In dry conditions, the water consumption of the Miúda clone responds more slowly to variation in soil water availability. The lower evolution of the CAI of the IPA Sertânia clone, during the rainy season, leads to a higher contribution of the evaporation component in ET. The atmospheric demand controls the ET of clones only when there is higher soil water availability; in this condition, the water consumption of the Miúda clone decreases more rapidly with the increase of atmospheric demand

Graphenes as Metal-Free Catalysts with Engineered Active Sites

[EN] This Perspective article highlights how recent discoveries on the activity of defective graphene to promote different organic reactions as metal-free catalysts has led to propose certain substructures present on these defective graphenes as active sites. The sustainability of using as catalysts graphenes obtained from biomass and the possibility to generate active sites by introducing defects on the sheet are the two main characteristics triggering research in this area. Emphasis is made in the need to gain understanding on the nature of the active sites and how this understanding requires the combination of conventional kinetic experiments as well as advanced characterization tools. The relationship between catalysis by graphene and that by organocatalysis has also been remarked.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa, Grapas, and CTQ2015-69153-CO2-1) and Generalitat Valenciana (Prometo 2013-014) is gratefully acknowledged. A.P. also thanks the Spanish Ministry of Economy and Competitiveness for a Ramon y Cajal research associate contract.Primo Arnau, AM.; Parvulescu, V.; García Gómez, H. (2017). Graphenes as Metal-Free Catalysts with Engineered Active Sites. The Journal of Physical Chemistry Letters. 8(1):264-278. https://doi.org/10.1021/acs.jpclett.6b01996S2642788

Consumo de carboidratos totais e de carboidratos não fibrosos em ovinos alimentados com dietas contendo soro de leite bovino.

Objetivou-se com o presente estudo, determinar o consumo de carboidratos totais e de carboidratos não fibrosos em ovinos alimentados com dietas contendo SLB em níveis crescentes

Características estruturais do capim-elefante adubado com composto orgânico proveniente da produção e do abate de pequenos ruminantes.

This study aimed to evaluate the morphophysiological characteristics of irrigated Pennisetum purpureum cv. Cameroon subjected to doses of an organic compost from waste generated by production and slaughter of small ruminants..

Avaliação nutricional do capim-elefante fertilizado com composto orgânico oriundo de resíduos da produção e abate de caprinos e ovinos?.

Resumo: Objetivou-se avaliar a composição química do capim-elefante adubado com crescentes doses de composto orgânico produzido a partir de resíduos da produção e abate de pequenos ruminantes. O delineamento foi em blocos casualizados com 6 tratamentos e 4 blocos, totalizando 24 parcelas, sendo aplicadas as seguintes doses (t ha-1): zero; 13,3; 26,6; 39,9; 53,2 e 79,8. Para a diagnose do estado nutricional do capim-elefante, coletou-se 7 amostras simples por parcela, em zigue-zague, de maneira aleatória. A região avaliada foi a primeira folha recém-expandida, sendo as amostras simples as plantas de uma mesma touceira, ao sexagésimo dia após o corte de uniformização. Avaliou-se a análise de macro e micronutrientes do capim-elefante. Houve efeito significativo para os macronutrientes primários nitrogênio, fósforo e potássio (NPK) e o micronutriente zinco. Conclui-se que a aplicação, na capineira, do composto orgânico proveniente de resíduos da produção e abate de pequenos ruminantes proporciona incremento nos teores foliares de N, P, K e Zn. [Evaluation of elephant grass fertilized with compound organic derived of production and slaugher of sheeps and goats]. Abstract: This study aimed to evaluate the nutritional status of elephant grass under doses of organic compound from production residue and slaughter of small ruminants after composting process. The experimental design was randomized blocks with 6 treatments and 4 blocks, total of 24 plots. The doses (t ha-1) applied were: zero; 13.3; 26.6; 39.9; 53.2 and 79.8. In order to diagnose the nutritional status of elephant grass we collected 40 single samples in random way in each plot. The chosen part was the first newly expanded leaf, and the single samples were plants of the same clump on the sixtieth day after the uniformity cut. We evaluated the chemical analysis of macronutrients and micronutrients in elephant grass. The results showed that there were significant effects on primary macronutrients nitrogen, phosphorus and potassium (NPK) and zinc micronutrient. The results show that the application of organic compound from production residue and slaughter of small ruminants provided an increase in the leaf levels of N, P, K and Zn

Dinâmica de água no solo em uma área de cultivo com clones de palma forrageira.

Objetivou-se analisar a dinâmica de água no solo de três clones (Miúda, IPA Sertânia e Orelha de Elefante Mexicana) de palma forrageira nas condições climáticas do Semiárido do Médio Pajeú. O monitoramento do conteúdo de água no solo (CAS) foi feito por meio de uma sonda capacitiva. Com os resultados, verificou-se que a magnitude dos valores de CAS foi inferior nas áreas cultivadas com a Miúda e a Orelha de Elefante Mexicana e superior nas áreas cultivadas com a IPA Sertânia, inferindo que os dois primeiros clones podem apresentar maior demanda de água quando comparado ao último clone, podendo estes resultados estarem associados a características inerentes ao índice de área de cladódio e aos seus respectivos gêneros, logo que a Miúda e IPA Sertânia são pertencentes ao gênero Nopalea sp. e a Orelha de Elefante Mexicana ao gênero Opuntia sp