Goulão, Luís F.; Fernandes, João C.; Amâncio, Sara
The noteworthy fine remodeling that plant cell walls (CWs) undergo to adapt to
developmental, physiological and environmental cues and the observation that its
composition and dynamics differ between species represents an opportunity to couple
crop species agronomic studies with research on CW modifications. Vitis vinifera is
one of the most important crops from an economic point-of-view due to the high
value of the fruit, predominantly for winemaking. The availability of some information
related to this species’ CWs allows researching its responses to imposed conditions that
affect the plant’s development. Mineral deficiency, in particular nitrogen, phosphorus,
potassium and sulfur, strongly affects plant metabolism, reducing both growth and
crop yield. Despite...
Ribeiro, Edna; Ladeira, Carina; Viegas, Susana
Ribeiro, Edna; Ladeira, Carina; Viegas, Susana
Monteiro, Filipa; Catarino, Luís; Batista, Dora; Indjai, Bucar; Duarte, Maria Cristina; Romeiras, Maria M.
Wu, Yao; Liu, Tingxi; Paredes, Paula; Duan, Limin; Pereira, L.S.
tThis study aimed at assessing the soil water balance, groundwater contribution, crop transpiration andsoil evaporation of a rainfed maize crop in Horqin sandy area, north-eastern Inner Mongolia, China.Two years of field data from the Agula site were used, 2008 with relatively high rainfall (363 mm) andhigh water table, and 2009 with low rainfall (125 mm) and lower water table. The SIMDualKc waterbalance model was calibrated with observed soil water content data of 2008 and validated with dataof 2009. The model uses the dual crop coefficient approach for evapotranspiration (ET) partitioning,and parametric functions for computing capillary rise. The respective modelling results...
Danalache, Florina; Beirão-da-Costa, Sara; Mata, Paulina; Alves, Vitor D.; Martins, Margarida Moldão
Studies for the development of a novel convenient fruit product based on mango puree and gellan gum
were carried out. Two gellan types (low acyl-L and high acyl-H) used in specific L/H ratios (75/25, 50/50,
25/75) for an overall concentration of 1 g of gellan/100 g of puree were tested, in order to design different
mango bars. The influence of the L/H gellan ratio on their texture properties (TPA and SR tests),
microstructure (Cryo-Scanning Electron Microscopy) and texture sensory acceptance (Preference-
Ranking test) was studied. The results obtained enabled to separate the bars in two groups: the ones
showing greater hardness and brittleness (only L gellan,...
Miao, Qingfeng; Shi, Haibin; Gonçalves, José M.; Pereira, L.S.
Fandiño, M.; Olmedo, J.L.; Martinez, E.M.; Valladares, J.; Paredes, P.; Rey, B.J.; Mota, M.; Cancela, J.J.; Pereira, L.S.
This study was conducted during three seasons (2012–2014) in an experimental hop yard at Mabegondo,Galicia, NW Spain. The research aimed at calibrating and validating the soil water balance model SIMD-ualKc for Humulus lupulus L. cv. ‘Nugget’. The model computes the soil water balance using the dualKcapproach, thus partitioning crop evapotranspiration (ETc) into crop transpiration, ground covertranspiration and soil evaporation. Calibration and validation were performed using TDR soil watercontent measurements, which produced small root mean square errors (RMSE) ranging from 0.012 to0.015 cm3cm−3. The initial, mid-season and end-season basal crop coefficients (Kcb) that allow com-puting hop transpiration were respectively 0.16, 0.97...
Nunes, José Manuel Rato; Bonito, António; Loures, Luís; Gama, José; López-Piñero, Antonio; Peña, David; Albarrán, Ángel
Agro-environmental measures promoted by the European Union focus mainly on
environmental protection by maintaining sustainable levels of productivity that are adequate to
the agro-ecological conditions of each region on different Member States. Among these European
Union promoted measures the one known as “Extensive Forage Systems” is particularly relevant
for the Mediterranean Region. In order to analyze the impact of this measure and to verify if the
high expenditure of communitarian funds, with its implementation in Mediterranean soils, is aligned
with the predicted benefits, a seven-year study in a southern Portugal region was conducted. In
this regard, several soil chemical parameters such as organic matter, pH, electrical conductivity,
Carmo, Miguel; Garcia-Ruiz, Roberto; Ferreira, Maria Isabel; Domingos, Tiago
Agricultural nutrient balances have been receiving increasing attention in both historical and
nutrient management research. The main objectives of this study were to further develop balance
methodologies and to carry out a comprehensive assessment of the functioning and nutrient cycling
of 1950s agroecosystems in Portugal. Additionally, the main implications for the history of agriculture
in Portugal were discussed from the standpoint of soil fertility. We used a mass balance approach
that comprises virtually all nitrogen (N), phosphorus (P) and potassium (K) inputs and outputs from
cropland topsoil for average conditions in the period 1951–56. We found a consistent deficit in N, both
for nationwide (−2.1 kg.ha−1.yr−1) and...
Pinheiro, Ana M.; Carreira, Alexandra; Prescott, Thomas A.K.; Ferreira, Ricardo Boavida; Monteiro, Sara A.
Branquinho, Cristina; Proença, Vania; Grilo, Filipa; Sardinha, Idalina Dias; Faria, Margarida Lima; Franco, José Carlos; Romeiras, Maria Manuel; Monteiro, Filipa; Goulão, Luís F.; Santos-Reis, Margarida
Santos, José Manuel Lima
Giménez, Luis; Paredes, Paula; Pereira, L.S.
Data relative to two soybean seasons, several irrigation scheduling treatments, including
moderate and severe deficit irrigation, and rain-fed cropping were used to parameterize and assess
the performance of models AquaCrop and SIMDualKc, the latter combined with the Stewart’s yield
model. SIMDualKc applies the FAO56 dual crop coefficient approach for computing and partitioning
evapotranspiration (ET) into actual crop transpiration (Tc act) and soil evaporation (Es), while
AquaCrop uses an approach that depends on the canopy cover curve. The calibration-validations of
models were performed by comparing observed and predicted soil water content (SWC) and grain
yield. SIMDualKc showed good accuracy for SWC estimations, with normalized root mean square
Ramôa, S.; Oliveira e Silva, P.; Vasconcelos, T.; Fortes, P.; Portugal, J.
The conclusion of the dam project located in Alqueva, in Southern Portugal, has
resulted in a significant increase of new irrigated areas, since 2006. This has meant that, in
recent years, there have been progressive flora changes in farming systems traditionally
implemented in the Alentejo region. The present work has analyzed the weed flora in an
early stage of these changes, and the impact of environmental factors on the distribution of
natural vegetation under Mediterranean climate conditions in the influence area of Alqueva.
In 2007, 105 floristic surveys were carried out in autumn-winter crop plots or other soil use,
and 264 species were identified. Families with higher...
Pôças, Isabel; Paço, Teresa Afonso; Paredes, Paula; Cunha, Mário; Pereira, L.S.
A new procedure is proposed for estimating actual basal crop coefficients from
vegetation indices (Kcb VI) considering a density coefficient (Kd) and a crop coefficient for
bare soil. Kd is computed using the fraction of ground cover by vegetation (fc VI), which is
also estimated from vegetation indices derived from remote sensing. A combined approach
for estimating actual crop coefficients from vegetation indices (Kc VI) is also proposed by
integrating the Kcb VI with the soil evaporation coefficient (Ke) derived from the soil water
balance model SIMDualKc. Results for maize, barley and an olive orchard have shown that
the approaches for estimating both fc VI and Kcb...
Chandra, Mahesh; Oro, Inês; Ferreira-Dias, Suzana; Malfeito-Ferreira, Manuel
Cerqueira, Reginaldo Conceição; Costa, Joaquim Miguel; Chaves, Maria Manuela; Rodrigues, João Domingos
Este trabalho teve como objetivo comparar duas variedades de videira cultivadas em Portugal, Syrah e Touriga Nacional, em
termos de suas respostas fisiológicas e bioquímicas a um ciclo de estresse hídrico severo seguido de reidratação. Os tratamentos
consistiram em videiras continuamente regadas (FI) e videiras não regadas durante 21 dias e reidratadas após o potencial hídrico
foliar de base (Ψpd) atingir cerca de -1,1MPa (NI). As observações ocorreram em quatro momentos: i) imediatamente antes de
suprimir a rega (dia 0), ii) no momento de máximo de estresse (dia 21), iii) dois dias após reidratação (dia 23) e iv) seis dias após
reidratação (dia 27). Mediu-se...
Roca, Christophe; Alves, Vitor D.; Freitas, Filomena; Reis, Maria A.M.
Shvaleva, Alla; Siljanen, Henri M.; Correia, Alexandra; Silva, Filipe Costa e; Lamprecht, Richard E.; Lobo-do-Vale, Raquel; Bicho, Catarina; Fangueiro, David; Anderson, Margaret; Pereira, João Santos; Chaves, Maria Manuela; Cruz, Cristina; Martikainen, Pertti J.