El control de la supervivencia en plantaciones agroforestales con waterboxx mediante vehículos aéreos no tripulados e información multiespectral

El avance de la tecnología está contribuyendo al surgimiento de técnicas de monitorización que facilitan una toma de datos de manera rápida, precisa y fiable. Los Vehículos Aéreos No Tripulados suponen una alternativa novedosa e interesante para elevar cámaras multiespectrales y realizar estudios de la vegetación y biomasa. Uno de los factores que más inciden en la supervivencia de las plantaciones agroforestales en climas áridos es el estrés hídrico. En los primeros estadios de crecimiento, cuando los plantones necesitan más humedad, el Waterboxx (©Groasis), un recipiente capaz de recoger y almacenar el agua de del rocío y de la lluvia, puede aportar la cantidad mínima de agua necesaria para que éstos sobrevivan. El Proyecto del Programa Europeo LIFE+: “Los Desiertos Verdes”, pretende comprobar si el uso de esta tecnología puede contribuir a aumentar la supervivencia de las plantas en climas extremos y suelos degradados. El control de la supervivencia e el sector agroforestal se ha venido realizando tradicionalmente mediante muestreos sistemáticos a pie de campo. En esta Tesis Doctoral nos planteamos como objetivo principal establecer una metodología que permita discriminar las plantas vivas de las muertas en Waterboxx mediante sensores aeroportados con aeronaves no tripuladas en parcelas de diferentes dimensiones. Durante un período de 5 años se han realizado 15 vuelos con diferentes combinaciones de plataformas aéreas y sensores multiespectrales. En la metodología desarrollada se han testado tres métodos diferentes estableciéndose relaciones entre tipo de cámara, resolución del sensor, altura de vuelo y tamaño y vigor de la planta. A través de cada uno de los vuelos, se han obtenido datos que se han procesado obteniendo ortofotos y ortomosaicos. Tras su tratamiento digital se ha realizado el análisis visual obteniéndose unos índices de Exactitud Global muy elevados con un porcentaje mínimo de plantas dudosas.Departamento de Ingeniería Agrícola y Foresta

Above-ground biomass estimation of arable crops using UAV-based SfM photogrammetry

This is an Accepted Manuscript of an article published by Taylor & Francis in Geocarto International on 3 dec 2018, available online: http://www.tandfonline.com/10.1080/10106049.2018.1552322Methods of estimating the total amount of above-ground biomass (AGB) in crop fields are generally based on labourious, random, and destructive in situ sampling. This study proposes a methodology for estimating herbaceous crop biomass using conventional optical cameras and structure from motion (SfM) photogrammetry. The proposed method is based on the determination of volumes according to the difference between a digital terrain model (DTM) and digital surface model (DSM) of vegetative cover. A density factor was calibrated based on a subset of destructive random samples to relate the volume and biomass and efficiently quantify the total AGB. In all cases, RMSE Z values less than 0.23 m were obtained for the DTMDSM coupling. Biomass field data confirmed the goodness of fit of the yieldbiomass estimation (R2=0,88 and 1,12 kg/ha) mainly in plots with uniform vegetation coverage. Furthermore, the method was demonstrated to be scalable to multiple platform types and sensorsThis work was supported by the life project “Operation CO2: Integrated Agroforestry Practices and Nature Conservation Against Climate Change - LIFE+ 11 ENV/ES/535” and by Xunta de Galicia under the grant “Financial aid for the consolidation and structure of competitive units of investigation in the universities of the University Galician System (2016-18)” Ref. ED431B 2016/030 and Ref. ED341D R2016/023.S

Plant survival monitoring with UAVs and multispectral data in difficult access afforested areas

This is an Accepted Manuscript of an article published by Taylor & Francis in Geocarto International on 02 Oct 2018, available online: http://www.tandfonline.com/10.1080/10106049.2018.1508312Water supply devices enable afforestation in dry climates and on poor lands with generally high success rates. Previous survival analyses have been based on the direct observation of each individual plant in the field, which entails considerable effort and costs. This study provides a low-cost method to discriminate between live and dead plants in afforestations that can efficiently replace traditional field inspections through the use of UAVs equipped with RGB and NIR sensors. The method combines the use of a conventional camera with an identical camera modified to record the NIR channel. Survival analysis was performed with digital image processing techniques based on calculated indices associated with plant vigour and PCA-based decorrelation. The method yielded results with high global accuracy rates (~96.2%) with a minimum percentage of doubtful plants, even in young plantations (seedlings < 30 cm tall). The procedure could be particularly useful in hazardous areasThis work was supported by the Xunta de Galicia under the Grant “Financial aid for the consolidation and structure of competitive units of investigation in the universities of the University Galician System (2016-18)” [ED431B 2016/030, ED341D R2016/023] and the European Program Life+ [LIFE/ENV/ES/000447] “The Green Deserts: New planting techniques for tree cultivation in desertified environments to face Climate Change”.S

Antifungal activity of chitosan oligomers-amino acid conjugate complexes against Fusarium culmorum in spelt (Triticum spelta L.)

Fusarium head blight (FHB) is a complex disease of cereals caused by Fusarium species, which causes severe damages in terms of yield quality and quantity worldwide, and which produces mycotoxin contamination, posing a serious threat to public health. In the study presented herein, the antifungal activity against Fusarium culmorum of chitosan oligomers (COS)–amino acid conjugate complexes was investigated both in vitro and in vivo. The amino acids assayed were cysteine, glycine, proline and tyrosine. In vitro tests showed an enhancement of mycelial growth inhibition, with EC50 and EC90 effective concentration values ranging from 320 to 948 µg·mL−1 and from 1107 to 1407 µg·mL−1 respectively, for the conjugate complexes, as a result of the synergistic behavior between COS and the amino acids, tentatively ascribed to enhanced cell membrane damage originating from lipid peroxidation. Tests on colonies showed a maximum percentage reduction in the number of colonies at 1500 µg·mL−1 concentration, while grain tests were found to inhibit fungal growth, reducing deoxynivalenol content by 89%. The formulation that showed the best performance, i.e., the conjugate complex based on COS and tyrosine, was further investigated in a small-scale field trial with artificially inoculated spelt (Triticum spelta L.), and as a seed treatment to inhibit fungal growth in spelt seedlings. The field experiment showed that the chosen formulation induced a decrease in disease severity, with a control efficacy of 83.5%, while the seed tests showed that the treatment did not affect the percentage of germination and resulted in a lower incidence of root rot caused by the pathogen, albeit with a lower control efficacy (50%). Consequently, the reported conjugate complexes hold enough promise for crop protection applications to deserve further examination in larger field trials, with other Fusarium spp. pathogens and/or Triticum species

Assessment of RGB vegetation indices to estimate chlorophyll content in sugar beet leaves in the final cultivation stage

Estimation of chlorophyll content with portable meters is an easy way to quantify crop nitrogen status in sugar beet leaves. In this work, an alternative for chlorophyll content estimation using RGB-only vegetation indices has been explored. In a first step, pictures of spring-sown ‘Fernanda KWS’ variety sugar beet leaves taken with a commercial camera were used to calculate 25 RGB indices reported in the literature and to obtain 9 new indices through principal component analysis (PCA) and stepwise linear regression (SLR) techniques. The performance of the 34 indices was examined in order to evaluate their ability to estimate chlorophyll content and chlorophyll degradation in the leaves under different natural light conditions along 4 days of the canopy senescence period. Two of the new proposed RGB indices were found to improve the already good performance of the indices reported in the literature, particularly for leaves featuring low chlorophyll contents. The 4 best indices were finally tested in field conditions, using unmanned aerial vehicle (UAV)-taken photographs of a sugar beet plot, finding a reasonably good agreement with chlorophyll-meter data for all indices, in particular for I2 and (R−B)/(R+G+B). Consequently, the suggested RGB indices may hold promise for inexpensive chlorophyll estimation in sugar beet leaves during the harvest time, although a direct relationship with nitrogen status still needs to be validated

Furfural, 5-HMF, acid-soluble lignin and sugar contents in C. ladanifer and E. arborea lignocellulosic biomass hydrolysates obtained from microwave-assisted treatments in different solvents

Cistus ladanifer L. and Erica arborea L. are the two most representative shrub species from the Iberian Peninsula. With a view to their valorization, their biomass hydrolysate components, obtained from microwave-assisted treatments with choline chloride/urea - HNO3 10%, N,N-dimethylacetamide/NaHCO3 and N,N-dimethylacetamide/CH3OK as solvents, have been measured using a spectrophotometric method. Concentrations of furfural and 5-(hydroxymethyl)furfural (5-HMF) in the filtrate have been determined after reduction with NaBH4. The production of total sugars, reducing sugars and non-reducing sugars has also been assessed. The obtained results support the choice of microwave-assisted choline chloride/urea deep eutectic solvent in acid media as the preferred method (over the polar aprotic solvent-based alternatives) for the extraction of lignin, furfural, 5-HMF and sugars from C. ladanifer and E. arborea biomass, attaining the best production yields for 60¿min exposure times. Another is the case if the aim of the treatments is to recovery sugars from both shrubs for subsequent enzymatic saccharification: the very low 5-HMF contents resulting from the dimetylacetamide systems (especially is association with CH3OK) make them highly advantageous as compared to the traditional method using NaOH

Crystallinity of cellulose microfibers derived from Cistus ladanifer and Erica arborea shrubs

The effectiveness of the use of cellulose fibers as particulates/composite reinforcers involves the assessment of the crystallinity of such fibers. The aim of the present work is to provide information on the degree of crystallinity of the cellulose microfibers obtained from the stems of Cistus ladanifer and Erica arborea shrubs through two different methods, namely an alkaline treatment and a microwave-assisted deep eutectic solvent (DES) method. The crystallinity indexes (CrI) obtained from X-ray powder diffraction patterns indicated that higher CrI were attained for cellulose obtained from the DES treatment. Complementary information on the degree of crystallinity was also retrieved from attenuated total reflection- Fourier transform infrared spectroscopy (ATR-FTIR) vibrational spectra, scanning electron microscopy (SEM) micrographs, and accessibility data for the DES-treated celluloses from the two species. The crystallinity results for the fibers derived from these two Mediterranean shrubs were within the range of the results for those derived from wood pulp, opening the door to their valorization for cellulose-derived packing applications or for their use as reinforcers in composite materials in combination with other biopolymers

Antifungal activity against Fusarium culmorum of stevioside, Silybum marianum seed extracts, and their conjugate complexes

Fusarium head blight (FHB) is a disease that poses a major challenge in cereal production that has important food and feed safety implications due to trichothecene contamination. In this study, the effect of stevioside—a glycoside found in the leaves of candyleaf (Stevia rebaudiana Bertoni)—was evaluated in vitro against Fusarium culmorum (W.G. Smith) Sacc., alone and in combination (in a 1:1 molar ratio) with polyphenols obtained from milk thistle seeds (Silybum marianum (L.) Gaertn). Different concentrations, ranging from 32 to 512 µg·mL−1, were assayed, finding EC50 and EC90 inhibitory concentrations of 156 and 221 µg·mL−1, respectively, for the treatment based only on stevioside, and EC50 and EC90 values of 123 and 160 µg·mL−1, respectively, for the treatment based on the stevioside–polyphenol conjugate complexes. Colony formation inhibition results were consistent, reaching full inhibition at 256 µg·mL−1. Given that synergistic behavior was observed for this latter formulation (SF = 1.43, according to Wadley’s method), it was further assessed for grain protection at storage, mostly directed against mycotoxin contamination caused by the aforementioned phytopathogen, confirming that it could inhibit fungal growth and avoid trichothecene contamination. Moreover, seed tests showed that the treatment did not affect the percentage of germination, and it resulted in a lower incidence of root rot caused by the pathogen in Kamut and winter wheat seedlings. Hence, the application of these stevioside–S. marianum seed extract conjugate complexes may be put forward as a promising and environmentally friendly treatment for the protection of cereal crops and stored grain against FHB

Sugar beet agronomic performance evolution in NW Spain in future scenarios of climate change

Changes in environmental conditions resulting from Climate Change are expected to have a major impact on crops. In order to foresee adaptation measures and to minimize yield decline, it is necessary to estimate the effect of those changes on the evapotranspiration and on the associated irrigation needs of crops. In the study presented herein, future conditions extracted from RCP4.5 scenario of IPCC, particularized for Castilla-y-León (Spain), were used as inputs for FAO crop simulation model (AquaCrop) to estimate sugar beet agronomic performance in the medium-term (2050 and 2070). A regional analysis of future trends in terms of yield, biomass and CO2 sequestration was carried out. An annual ET0 increase of up to 200 mm was estimated in 2050 and 2070 scenarios, with ETc increases of up to 40 mm/month. At current irrigation levels, temperature rise would be accompanied by a 9% decrease in yield and a ca. 6% decrease in assimilated CO2 in the 2050 and 2070 scenarios. However, it is also shown that the implementation of adequate adaptation measures, in combination with a more efficient irrigation management, may result in up to 17% higher yields and in the storage of between 9% and 13% higher amounts of CO2

Valorization of Cistus ladanifer and Erica arborea shrubs for fuel: Wood and bark thermal characterization

As a form of upgraded biomass characterized by its high energy density, low production costs, and low process energy requirements, wood pellets are an environmentally friendly fuel allowing for carbon neutral heating with high energy efficiency. In this work, the suitability of a valorization of the woods from the two most representative shrub species from the Iberian Peninsula (namely Cistus ladanifer and Erica arborea) for heating has been assessed. Whereas Erica arborea met the requirements of ISO 17225-2:2014 for ENplus-B class (the calorific content for both wood and bark was high and not significantly different, and the ash content was permissible for specimens with branch diameter ≥2,8 cm), Cistus ladanifer was in the limit of the normative and only met the requirements in terms of acceptable ash percentage (1,9%) and heating value (19 kJ·g-1) for old specimens with branch diameters &gt;3,4 cm. Consequently, while the harvest of E. arborea for its use as fuel does not need to be selective, that of C. ladanifer should be limited to the most robust specimens and foliage should be avoided. &nbsp;&nbsp;PDF XM