Ultrasonic and LIDAR sensors for electronic canopy characterization in vineyards: advances to improve pesticide application methods

Canopy characterization is a key factor to improve pesticide application methods in tree crops and vineyards. Development of quick, easy and efficient methods to determine the fundamental parameters used to characterize canopy structure is thus an important need. In this research the use of ultrasonic and LIDAR sensors have been compared with the traditional manual and destructive canopy measurement procedure. For both methods the values of key parameters such as crop height, crop width, crop volume or leaf area have been compared. Obtained results indicate that an ultrasonic sensor is an appropriate tool to determine the average canopy characteristics, while a LIDAR sensor provides more accuracy and detailed information about the canopy. Good correlations have been obtained between crop volume (CVU) values measured with ultrasonic sensors and leaf area index, LAI (R2 = 0.51). A good correlation has also been obtained between the canopy volume measured with ultrasonic and LIDAR sensors (R2 = 0.52). Laser measurements of crop height (CHL) allow one to accurately predict the canopy volume. The proposed new technologies seems very appropriate as complementary tools to improve the efficiency of pesticide applications, although further improvements are still needed.

Phosphorous and nitrogen changes in compost-amended schist soils in vineyards in the D.O. Priorat wine-producing area (NE Spain)

The impact, on nitrogen and phosphorous dynamics, of applying compost at different rates was investigated in soils developed on schist in new terraced vineyards (NTV) and in undisturbed areas (NC). Repacked soil columns amended with 0 (control), 50 t ha –1 (T1) and 100 t ha–1 (T2) of compost were studied under laboratory conditions simulating both situations. The columns were maintained for 1 year, during which time a total of 300 mm of simulated rainfall was applied in ten 30 mm applications. Soil organic matter (OM), nitrogen and phosphorous contents were analysed at the end of the study period and leachates were analysed after each simulated rainfall event. Significant differences in nitrate leaching were observed between the control and the treated soils and these differences were greater in the NC (control = 1.368 g, T1 = 1.526 g and T2 = 1.686 g) than in the NTV soils (control = 0.61 g, T1 = = 1.068 g and T2 = 1.283 g). The relative effect was greater in the NTV soils (T1/control = 1.11 vs. 1.75 and T2/control = 1.23 vs. 2.1 for NC and NTV, respectively). The nitrate concentration in the leached water reached up to 400 mg L–1, which implied a risk of groundwater pollution. Phosphorous losses through leaching were very low with concentrations of < 0.15 mg L–1, without any significant differences between treatments. The phosphorous concentrations in the surface horizon increased by 50.8% in T1 and by 66.8% in T2 in the NC soils, compared with increases of 20.3% and 38%, respectively, in the NTV soils. Due to the high infiltration capacity of the study soils, leaching effects must be considered in order to prevent groundwater pollution.

Fauna silvestre del Parc del Garraf. Afectacions al sector primari

El Parc del Garraf (PG) ha estat tradicionalment una important zona agrícola, encara que actualment és molt reduïda (representa el 3% del total de la superfície del parc) i està repartida entre unes poques masies. Aquesta activitat humana conviu amb la fauna silvestre de la zona, que en alimentar-se parcialment dels cultius (cereal, vinya, oliveres, arbres fruiters i hortalisses), hi causa diversos impactes. És el cas de diverses aus, com ara la garsa (Pica Pica) i el pardal (Passer domesticus), i també d’alguns mamífers com el porc senglar (Sus scrofa). Hem observat que l’impacte produït per les aus i el porc senglar (Sus scrofa) és molt petit, el que pot ser degut a dos motius principals: possiblement per una elevada producció de fruits salvatges, esdevenint aquest aliment suficient per a les aus; i la baixa densitat poblacional de porc senglar (Sus scrofa) al parc. Els impactes observats presenten una alta variabilitat i depenen de l’època de l’any en que ens trobem. Per tant, cal fer-ne un seguiment més acurat on s’impliquin administració i pagesos per a millorar el coneixement de l’impacte de la fauna salvatge.

La transformació del paisatge del delta de la Tordera en els darrers cent cinquanta anys : una anàlisi per mitjà dels canvis en els usos i les cobertes del sòl

This article compares the mid-nineteenth century landscape of the River Tordera delta with the present day landscape, based, above all, on the changes that have occurred in land use and land cover. The mid 19th century landscape was reconstructed using data obtained from the amillaraments (land inventories) and other historical documents. Present-day land use and cover was established through photo interpretation and field work. The most important changes detected concern the almost complete disappearance of certain crops, such as vineyards, which were very important in the 19th century; the expansion of forest in place of abandoned tilled land and the increase in built up areas, which, taken together, produce a highly fragmented landscape pattern

Clustering of grape yield maps to delineate site-specific management zones

Zonal management in vineyards requires the prior delineation of stable yield zones within the parcel. Among the different methodologies used for zone delineation, cluster analysis of yield data from several years is one of the possibilities cited in scientific literature. However, there exist reasonable doubts concerning the cluster algorithm to be used and the number of zones that have to be delineated within a field. In this paper two different cluster algorithms have been compared (k-means and fuzzy c-means) using the grape yield data corresponding to three successive years (2002, 2003 and 2004), for a ‘Pinot Noir’ vineyard parcel. Final choice of the most recommendable algorithm has been linked to obtaining a stable pattern of spatial yield distribution and to allowing for the delineation of compact and average sized areas. The general recommendation is to use reclassified maps of two clusters or yield classes (low yield zone and high yield zone) and, consequently, the site-specific vineyard management should be based on the prior delineation of just two different zones or sub-parcels. The two tested algorithms are good options for this purpose. However, the fuzzy c-means algorithm allows for a better zoning of the parcel, forming more compact areas and with more equilibrated zonal differences over time.

Cartografía de la actividad erosiva de paredes de barrancos a partir de imágenes de teledetección

El presente trabajo muestra una metodología para la determinación del grado de actividad erosiva de paredes de barrancos, fenómenos erosivos muy frecuentes en el área Mediterránea. La metodología se basa en la identificación del tipo de cubierta vegetal y grado de recubrimiento de las paredes a partir de imágenes multiespectrales de resolución media (Landsat TM). El área de estudio se localiza en las comarcas de l'Alt Penedes y l'Anoia (Barcelona), donde el principal cultivo son los viñedos. En esta región se ha desarrollado una red de barrancos de grandes dimensiones. Los resultados, según la metodología aplicada, indican que la mayor parte de las paredes de los barrancos presentan un alto grado de estabilidad debido a que mayoritariamente están cubiertas por vegetación de tipo matorral arbolado y bosque mixto. Sin embargo, los procesos erosivos detectados mediante observaciones de campo indican que la determinación del grado de actividad erosiva a partir de imágenes de resolución media produce resultados por defecto.

Soil quality assessment through a multi-approach analysis in soils of abandoned terraced land in NE Spain

The abandonment of agricultural land in mountainous areas has been an outstanding problem along the last century and has captured the attention of scientists, technicians and administrations, for the dramatic consequences sometimes occurred due to soil instability, steep slopes, rainfall regimes and wildfires. Hidromorfological and pedological alterations causing exceptional floods and accelerated erosion processes has therefore been studied, identifying the cause in the loss of landscape heterogeneity. Through the disappearance of agricultural works and drainage maintenance, slope stability has resulted severely affected. The mechanization of agriculture has caused the displacement of vines, olives and corks trees cultivation in terraced areas along the Mediterranean catchment towards more economically suitable areas. On the one hand, land use and management changes have implicated sociological changes as well, transforming areas inhabited by agricultural communities into deserted areas where the colonization of disorganized spontaneous vegetation has buried a valuable rural patrimony. On the other hand, lacking of planning and management of the abandoned areas has produced badlands and infertile soils due to wildfire and high erosion rates strongly degrading the whole ecosystems. In other cases, after land abandonment a process of soil regeneration has been recorded. Investigations have been conducted in a part of NE Spain where extended areas of terraced soils previously cultivated have been abandoned in the last century. The selected environments were semi-abandoned vineyards, semi-abandoned olive groves, abandoned stands of cork trees, abandoned stands of pine trees, scrubland of Cistaceaea, scrubland of Ericaceaea, and pasture. The research work was focused on the study of most relevant physical, chemical and biological soil properties, as well as runoff and erosion under soils with different plant cover to establish the abandonment effect on soil quality, due to the peculiarity and vulnerability of these soils with a much reduced depth. The period of observation was carried out from autumn 2009 to autumn 2010. The sediment concentration of soil erosion under vines was recorded as 34.52 g/l while under pasture it was 4.66 g/l. In addition, the soil under vines showed the least amount of organic matter, which was 12 times lower than all other soil environments. The carbon dioxide (CO2) and total glomalin (TG) ratio to soil organic carbon (SOC) in this soil was 0.11 and 0.31 respectively. However, the soil under pasture contained a higher amount of organic matter and showed that the CO2 and TG ratio to SOC was 0.02 and 0.11 respectively indicating that the soil under pasture better preserves the soil carbon pool. A similar trend was found in the intermediate soils in the sequence of land use change and abandonment. Soil structural stability increased in the two soil fractions investigated (0.25-2.00 mm, 2.0-5.6 mm) especially in those soils that did not undergo periodical perturbations like wildfires. Soil quality indexes were obtained by using relevant physical and chemical soil parameters. Factor analysis carried out to study the relationship between all soil parameters allowed to related variables and environments and identify those areas that better contribute to soil quality towards others that may need more attention to avoid further degradation processes

Distribution Patterns of Soil Properties in a Rural Mediterranean Area in Northeastern Spain

Soil properties on the Cap de Creus Peninsula, NE Spain depend primarily on scarce agricultural practices and early abandonment. In the study area, 90% of which is mainly covered by Cistus shrubs, 8 environments representing variations in land use/land cover and soil properties at different depths were identified. In each environment variously vegetated areas were selected and sampled. The soils, collected at different depths, were classified as Lithic Xerorthents according to the United States Department of Agriculture system of soil classification (USDA-NRCS 1975). Differences in soil properties were largely found according to the evolution of the plant canopy and the land use history. To identify underlying patterns in soil properties related to environmental evolution, factor analysis was performed and factor scores were used to determine how the factor patterns varied between soil variables, soil depths and selected environments. The three-factor model always accounted for 80% of the total variation in the data at the different soil depths. Organic matter was the more relevant soil property at 0–2 cm depth, whereas active minerals (silt and clay) were found to be the most relevant soil parameters controlling soil dynamics at the other depths investigated. Results showed that vineyards and olive tree soils are poorly developed and present worse conditions for mineral and organic compounds. Analysis of factor scores allowed independent assessment of soils, depth and plant cover and demonstrated that soils present the best physico-chemical characteristics under Erica arborea and meadows. In contrast, soils under Cistus monspeliensis were less nutrient rich and less well structured