Proteger as funções do solo – Assegurar a vida da Terra

Súmula baseada em algumas das comunicações apresentadas no Encontro Anual das Ciências do Solo - 2015: "Proteger as funções do solo – Assegurar a vida da Terra". Castelo Branco. Instituto Politécnico de Castelo Branco

Development of ternary diagrams for estimating water retention properties using geostatistical approaches

Most pedotransfer functions (PTFs) have adopted soil texture information as the main predictor to estimate soil hydraulic properties, whether inputs are defined in terms of the relative proportion of different grain size particles or texture-based classifications. The objective of this studywas to develop ternary diagrams for estimating soil water retention (θ) at−33 and−1500 kPa matric potentials, corresponding to the field capacity and wilting point, respectively, from particle size distribution using two geostatistical approaches. The texture triangle was divided into a 1% grid of soil texture composition resulting in 4332 different soil textures. Measured soil water retention values determined in 742 soil horizons/layers located in Portugal were then used to develop and validate the hydraulic ternary diagrams. The development subset included two-thirds of the data, and the validation subset the remaining samples. The measured soil water content values were displayed in the ternary diagram according to the coordinates given by the particles size distribution determined in the same soil samples. The volumetric water content values were then predicted for the entire ternary diagram using two different geostatistical interpolation algorithms (ordinary kriging and the empirical best linear unbiased predictor). Uncertainty analysis resulted in a root mean square error below 0.040 and 0.034 cm3 cm−3 when comparing the interpolated water contents at −33 and −1500 kPa matric potential values, respectively, with the measured ones included in the validation dataset. The estimation variance calculated with both methods was also considered to access the uncertainty of the predictions. The available water content of Portuguese soils was then derived from θ−33 kPa and θ−1500 kPa ternary diagrams developed with both approaches. The hydraulic ternary diagrams may thus serve as simplified tools for estimating water retention properties from particle size distribution and eventually serve as an alternative to the traditional statistical regression and data mining techniques used to derive PTFsinfo:eu-repo/semantics/publishedVersio

Corrigendum to “Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation” [Sci. Total Environ., 729 (2020) Start page – End page/ 138745]

info:eu-repo/semantics/publishedVersio

Estado de nutrição de pomares de pessegueiro na região da Beira Interior

A Beira Interior possui a principal área portuguesa de produção de pêssego (1803 ha) e possui também o know-how sobre esta cultura, existindo a única indicação geográfica protegida de pêssego do país – IGP pêssego da Cova da Beira, canais de comercialização, assistência técnica e ações de I&D. Paralelamente existe uma constante procura de conhecimento e inovação por parte dos produtores de modo a maximizarem o rendimento da cultura. Sendo a fertilização uma técnica com baixo peso nos custos de produção, aproximadamente 8%, é frequente existirem excessos para atingir produções mais elevadas. A fertilização reflete-se na disponibilidade de nutrientes e no estado de nutrição dos pomares que, com a rega, é determinante para o equilíbrio das plantas, para o seu vigor e produção e para a resistência a pragas ou doenças. A monitorização, desde a instalação, de 28 pomares localizados na região da Beira Interior, permitiu avaliar o estado de nutrição ao 3º ciclo vegetativo. Os resultados indicam que apesar do solo apresentar maioritariamente níveis altos de P e K, 45% dos pomares apresentaram teores foliares de K inferiores ao intervalo de referência. Também o teor de Zn se encontra em níveis inferiores a esse intervalo em 50% dos pomares.info:eu-repo/semantics/publishedVersio

A PRND polymorphism in Churra do Campo portuguese sheep breed

Prion-like Doppel gene (PRND) is located downstream from priori protein gene (PRNP). Doppel protein is not related to prion disease but to male fertility. Our previous analysis of PRND coding region in 460 animals from 8 Portuguese sheep breeds, by multiple restriction fragment-single strand conformation polymorphism (MRFSSCP), revealed a synonymous substitution (78G>A). An association was found between identified PRND polymorphism and PRNP genotypes, determined by primer extension and grouped into 5 grades of increasing scrapie susceptibility-R1 to R5: PRND was monomorphic (GG) in animals with most resistant ARR/ARR PRNP genotype-R1; higher frequency of heterozygotes (GA) was significantly associated with ARQ/AHQR4. Therefore, EU selection programme to eradicate scrapie in sheep, based on PRNP genotypes, may reduce genetic diversity, with hypothetical repercussions on reproduction. The aim of current work was to evaluate 78G>A PRND polymorphism in highly endangered Churra do Campo Portuguese sheep breed. From a total of 73 animals analysed (16 R1, 36 R3, 18 R4, 3 R5), 72 were GG and 1 GA, the later being ARQ/ARQ (R4). Low incidence of PRND polymorphic variants in this breed may be explained by mating involving small number of related animals, and particular differences in distribution of PRNP genotypes