Effects of Microalgal Food Quantity on Several Productivity-Related Parameters of the Calanoid Copepod Bestiolina similis (Calanoida: Paracalanidae)

The optimization of copepod feeding protocol is paramount to improve culture productivity and to maintain favorable water quality parameters overtime, as well as saving operational costs by preventing the production of unnecessary quantities of microalgae. The influence of microalgal feeding concentration on major parameters related to culture productivity of the calanoid copepod Bestiolina similis (Paracalanidae) was investigated in a series of laboratory experiments. B. similis was fed eight different concentrations (0, 150, 300, 600, 900, 1,200, 1,500 and 1,800 μgC l–1) of a mixed microalgal diet consisting of Tahitian strain of Isochrysis species, Pavalova 50 and Tetraselmis chuii at 1:1:1 carbon ratio. The results indicate that female daily and cumulative egg production over lifespan, egg hatching rate, naupliar and copepodite survival and development, adult female life expectancy, population growth and fecal pellet production rate (FPPR) were all significantly affected by microalgae feeding ration. Conversely, no significant influence could be established between microalgae food concentration and egg diameter or adult sex ratio. Feeding rations as low as 150 μgC l–1 led to lower egg hatching rates, survival and development, adult female life expectancy and population growth compared with the higher microalgae rations tested. Feeding concentration ≤ 900 μgC l–1 significantly limited female daily egg and fecal pellet production rate, as well as their cumulative egg production over lifespan, when compared to a level of 900 μgC l–1. Bestiolina similis fed with 1,200 μgC l–1 significantly improved female egg and fecal pellet production when compared to the lower treatments and was responsible for the highest female lifespan egg production and population growth observed among all treatments. Feeding rations as high as 1,500 μgC l–1 and 1,800 μgC l–1 did not lead to significant improvement in any of the parameters measured. This is likely due to a saturation effect at high food concentration which is known to decrease calanoid copepods feeding efficiency. Finally, B. similis FPPR, used as a proxy for ingestion, was found to saturate at a microalgae concentration of 783.4 μgC l–1 using a non-linear Michael-Menton (2 parameters), indicating that CVI female ingestion did not increase significantly above this concentration. Based on the above results it is recommended that B. similis cultures should be fed at a concentration of 1,200 μgC l–1, and not above, as rations > 1,200 μgC l–1 will not significantly improve any of the productivity-related parameters observed in this study. Feeding rations should never be below 783.40 μgC l–1 as this is the threshold level below which adult female ingestion rates become limiting.

Long-Term Cultivation of a Native Arthrospira platensis (Spirulina) Strain in Pozo Izquierdo (Gran Canaria, Spain): Technical Evidence for a Viable Production of Food-Grade Biomass

Microalgae cultivation is a promising alternative to traditional agriculture in arid—semi-arid areas. The aim of this study is to assess the viability of long-term cultivation of native Arthrospira platensis in Gran Canaria. Maximum culture productivity (0.08 g/L/day) and optimal concentration range (0.6–0.9 g/L) were firstly determined in 8000 L raceway under a greenhouse. Afterwards, a stable productivity of 0.06 g/L/day (6.0 g/m2/day) was obtained by reusing the culture medium during 26 days of cultivation, with consistent biomass biochemical composition. Outdoor temperature and daily solar irradiation ranged between 17.9–30.7 °C and 79.2–274.8 W/m2, while culture pH and salinity were in the range 9.42–10.77 and 11.2–14.9 g/L, respectively. Protein (>60%), potassium (1.8 g/100 g) and C-phycocyanin (7.2%) content is in the high-range of commercial Spirulina, which makes BEA 1257B promising for food and extraction of natural pigments/antioxidants. The dried biomass complies with international standards for human consumption, because of low heavy metal content and no pathogens presence. Product quality can be improved by reducing ash (≃12%) and sodium (1.5%) content through biomass washing optimization and/or further dewatering step. Other microorganisms can be prevented by high alkaline conditions and mild chemical treatments. These results pave the way for a sustainable microalgae-based blue bioeconomy in the Canary Islands.

Culture, productivity and competitiveness: disentangling the concepts

PurposeCulture has been identified as one of the main drivers of the “competitive productivity” (CP) of nations. However, research studies examining the relationships between culture, competition and productivity are highly fragmented across different streams of literature, leaving researchers with a lack of a holistic view of the topic. This study reviews research studies that examined the relationships between culture and productivity and between culture and competitiveness, as well as the joint relationships between culture, productivity and competitiveness in leading economic, business and management journals in the period 2009–2018 in order to identify research gaps and opportunities for future research.Design/methodology/approachThe authors used a combination of bibliometric analysis using VOSviewer, text analysis using Leximancer and systematic review by expert reviewers to analyze 293 articles that consider culture, productivity and competitiveness published in leading business, management and economics journals in the period 2009–2018.FindingsThe findings indicate that, although productivity and competitiveness are often discussed jointly in some policy circles, research studies on the roles of culture on productivity and on competitiveness take place in quite different streams of academic literature, drawing on different sets of concepts and theoretical frameworks. The concept of innovation appears prominently in both sets of the literature as an antecedent of both productivity improvement and international competitiveness.Research limitations/implicationsThe findings highlight the need for more research studies which jointly examine culture, productivity and competitiveness and the relationships between them.Originality/valueTo the best of the authors’ knowledge, this study is among the first attempts to systematically analyze the literature on the relationship between culture and CP.

MODELOS AGROMETEOROLÓGICOS PARA ESTIMATIVA E COMPARATIVO DE QUEBRA DE PRODUTIVIDADE DA CULTURA DO MILHO*

MODELOS AGROMETEOROLÓGICOS PARA ESTIMATIVA E COMPARATIVO DE QUEBRA DE PRODUTIVIDADE DA CULTURA DO MILHO* TAISE CRISTINE BUSKE1; ADROALDO DIAS ROBAINA2; MARCIA XAVIER PEITER3 E ROGÉRIO RICALDE TORRES4 1 Engenheira Agrônoma; Doutora em Engenharia Agrícola; Docente do Instituto Federal Catarinense – Campus Santa Rosa do Sul, Rua das Rosas s/n - Cx. Postal 04 - CEP 88965-000 - Santa Rosa do Sul/ SC, Brasil; E-mail: [email protected] 2 Engenheiro Agrônomo; Doutor; Professor Titular; Departamento de Engenharia Rural; Universidade Federal de Santa Maria, Av. Roraima nº 1000 - Cidade Universitária - Bairro Camobi – CEP 97105-900 - Santa Maria/ RS, Brasil; E-mail: [email protected] 3 Engenheira Agrônoma; Doutora; Professora Adjunta; Departamento de Engenharia Rural; Universidade Federal de Santa Maria, , Av. Roraima nº 1000 - Cidade Universitária - Bairro Camobi – CEP 97105-900 - Santa Maria/ RS, Brasil; E-mail: [email protected] 4 Engenheiro Agrônomo; Doutor; Docente do Instituto Federal do Rio Grande do Sul – Campus Vacaria, Estrada Engenheiro João Viterbo de Oliveira, 3061 - Zona Rural - CEP: 95219-899, Vacaria/ RS, Brasil; E-mail: [email protected] * O artigo foi gerado a partir da tese do primeiro autor. 1 RESUMO A agricultura do Rio Grande do Sul é caracterizada pela predominância de culturas de primavera-verão, as quais tem sua produção afetada pelo déficit hídrico. Assim, objetivou-se estimar a produtividade da cultura do milho com os modelos agrometeorológicos e avaliar as quebras de rendimento da cultura na microrregião de Cruz Alta. Para estimar a produtividade real da cultura foram adotados os modelos agrometeorológicos de Jensen (1968), Minhas, Parikh e Srinivasan (1974) e, Doorenbos e Kassan (1979), todos com parâmetros ajustados. A precisão da estimativa foi determinada a partir de análise de regressão linear e correlação. Ainda, foram simuladas as quebras de rendimento para cada ano avaliado, no período de 1993-2014. O desempenho variou de “mau” até “muito bom”, sendo que os modelos de Jensen e Minhas, Parikh e Srinivasan foram classificados como “muito bom” em outubro e novembro. Recomendam-se os coeficientes -0,768, 0,699, 0,374 e -0,330 para o modelo de Jensen, e -1,438, 1,078, 0,439 e -0,442 para o modelo de Minhas, Parikh e Srinivasan, conforme o estádio fenológico. Também, observou-se quebra de rendimento na maioria dos anos estudados, notoriamente nas faixas maiores de 30% de perda de produtividade, podendo atingir frequência relativa de 30% para outubro, novembro e dezembro. Palavras-chave: déficit hídrico, modelagem, quebra de rendimento. BUSKE, T. C.; ROBAINA, A. D.; PEITER, M. X.; TORRES, R. R. AGROMETEOROLOGICAL MODELS FOR ESTIMATION AND COMPARATIVE BREAKDOWN OF MAIZE CULTURE PRODUCTIVITY 2 ABSTRACT Agriculture in the state of Rio Grande do Sul is predominant in spring-summer crops, whose production is affected by water deficit. This study aimed to estimate maize productivity with agrometeorological models and to evaluate crop yield losses in the Cruz Alta micro region. Agrometeorological models, with adjusted parameters of Jensen (1968), Minhas, Parikh and Srinivasan (1974) and, Doorenbos and Kassan (1979) were adopted to estimate the actual productivity of the crop. The accuracy of the estimation of each model was determined by linear regression analysis and correlation. Also, yield breaks were simulated for each year, in the period of 1993-2014. The performance ranged from “poor” to “very good”, with Jensen's and Minhas, Parikh and Srinivasan models being rated “very good” in October and November. The recommended coefficients are -0.768, 0.699, 0.374 and -0.330 for Jensen’s model, and -1.438, 1.078, 0.439 and -0.442 for Minhas, Parikh and Srinivasan’s model, according to the phonological stage. It was also observed a yield break in most of the years, notoriously where productivity loss is higher than 30%, reaching relative frequency of 30% for October, November and December. Keywords: water deficit, modeling, break of yield.

Effectiveness of repeated usage of the modified Zarrouk culture medium for cultivation of Spirulina platensis

Spirulina (Arthrospira) platensis biomass has a wide range of applications in several industries. One of the key issues for its production is the reduction of the culture medium cost. Here we have shown the possibility of a single recycling (repeated usage) of the modified Zarrouk nutrient medium (MZM; which contains 8.4 g/l of NaHCO3and 0.1 g/l of NaOH instead of 16.8 g/l of NaHCO3) for spirulina cultivation without altering culture productivity, photosynthetic pigments and protein contents in its biomass given that technological approach consisting in application of a mixture of a freshly prepared and once recycled modified Zarrouk medium in a ratio of 1:1 by volume is used. The obtained results can be applied for further reduction of costs of spirulina biomass production compared to methods described in previous studies.

FREQUÊNCIA DA FERTIRRIGAÇÃO FOSFATADA NA PRODUTIVIDADE DA CULTURA DA MELANCIA

FREQUÊNCIA DA FERTIRRIGAÇÃO FOSFATADA NA PRODUTIVIDADE DA CULTURA DA MELANCIA BENITO MOREIRA DE AZEVEDO1; CARLOS NEWDMAR VIEIRA FERNANDES2; JOAQUIM RAIMUNDO DO NASCIMENTO NETO3; THALES VINÍCIUS DE ARAÚJO VIANA1; DENISE VIEIRA VASCONCELOS3 E CHRISLENE NOJOSA DIAS FERNANDES3 [1]Departamento de Engenharia Agrícola, CCA/UFC, Av. Mister Hull, s/n, Bloco 804. Caixa Postal 12.168, Fortaleza, CE, Brasil, 60.455 970, [email protected], [email protected] Federal de Educação Ciência e Tecnologia do Ceará (IFCE), Campus Iguatu, Rodovia CE-060, Cajazeiras 63503-790 – Iguatu, CE, Brasil. [email protected] de Pós-Graduação em Engenharia Agrícola, CCA/UFC, Av. Mister Hull, s/n, Bloco 804. Caixa Postal 12.168, Fortaleza-CE, Brasil, 60.455 970, [email protected], [email protected], [email protected] 1 RESUMO A melancia (Citrullus lanatus) tem grande importância socioeconômica para o Nordeste brasileiro, onde o cultivo sob irrigação vem crescendo e permitindo ao produtor ofertar frutos de melhor qualidade. Objetivou-se avaliar a influência de frequências de fertirrigação fosfatada nos componentes de produção e produtividade da melancia. O delineamento adotado foi o de blocos ao acaso constituído por seis tratamentos, referentes a seis frequências de fertirrigação com fósforo, sendo: 2, 4, 8, 16, 32 e 64 fertirrigações no ciclo e quatro repetições. As variáveis analisadas foram: produtividade comercial; massa média do fruto; diâmetro polar; diâmetro equatorial; espessura da casca e teor de sólidos solúveis. O aumento da frequência de fertirrigação fosfatada proporcionou um melhor desempenho da cultura da melancia. As variáveis produtividade comercial e espessura da casca foram influenciadas significativamente pelas frequências de fertirrigação com fósforo, tendo as mesmas apresentado resposta linear. A frequência de fertirrigação fosfatada de 64 fertirrigações no ciclo de cultivo proporcionou a maior produtividade da melancia. Palavras-chave: Citrullus lanatus; quimigação; ácido fosfórico; adubação fosfatada. AZEVEDO, B. M. de; FERNANDES, C. N. V.; NASCIMENTO NETO, J. R. do; VIANA, T. V. de A.; VASCONCELOS, D. V.; FERNANDES, C. N. D.FREQUENCY OF FERTIRRIGATION WITH PHOSPHATE IN WATERMELON CULTURE PRODUCTIVITY 2 ABSTRACT Watermelon (Citrullus lanatus) is of great socioeconomic importance for the Brazilian Northeast, where crop under irrigation has increased and allowed the producer to offer the best quality fruits. This study aimed to evaluate the influence of frequency of fertirrigation with phosphate components on watermelon production and productivity. The study design was a randomized block consisting of six treatments, referring to six frequencies of fertirrigation with phosphorus, as follows: 2, 4, 8, 16, 32 and 64 in fertigation cycle and four replications. The variables analyzed were: commercial productivity; fruit weight; polar diameter; equatorial diameter; shell thickness and soluble solids. The increased frequency of phosphorus fertirrigation provided a better performance of the watermelon crop. The variables commercial productivity and shell thickness were significantly influenced by the frequencies of fertirrigation with phosphorus, and presented the same linear response. The 64 frequency of phosphorus fertirrigation of the crop cycle provided the greatest productivity of watermelon. Keywords: Citrullus lanatus; chemigation; phosphoric acid; phosphate fertilization.