Deposition of litter and nutrients in leaves and twigs in different plant communities of northeastern Mexico     

Humberto González-Rodríguez  Roque Gonzalo Ramírez-Lozano  Israel Cantú-Silva  Marco Vinicio Gómez-Meza  Eduardo Estrada-Castillón  José Ramón Arévalo 《林业研究》2018,29(5):1307-1314

Studies on litterfall and decomposition provide estimations of decomposition rates of different ecosystems.This is key information to understanding ecosystem dynamics and changes in a scenario of global warming.The objective of this research was to assess litterfall production,the potential deposition of macro and micronutrients through leaf and twig fall as well as macronutrient—use efficiency in three forest ecosystems at different altitudes: a pine forest mixed with deciduous species(S1); a Quercus spp.forest(S2); and,a Tamaulipan thornscrub forest(S3).Total annual litterfall deposition was 594,742 and 533 g m~(-2) for S1,S2 and S3.Leaf litter was higher (68%) than twigs(18%),reproductive structures(8%) or miscellaneous material(6%).Micronutrient leaf deposition was higher for Fe followed by Mn,Zn and Cu.Macronutrient leaf deposition was higher for Ca followed by K,Mg and P.Even though P deposition in leaves and twigs was lower than other macronutrients,its nutrient use efficiency was higher than Ca,Mg or K.Altitude and species composition determine litter and nutrient deposition,with higher values at mid-altitudes(550 m).Altitude is an important factor to consider when analyzing litter production as well as nutrient deposition as shown in this study.Litter production and nutrient deposition are expected to change in a scenario of global warming.  相似文献   

Comparative analysis of texture descriptors in maize fields with plants,soil and object discrimination     

Yerania Campos  Humberto Sossa  Gonzalo Pajares 《Precision Agriculture》2017,18(5):717-735

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Fleets of robots for environmentally-safe pest control in agriculture     

Pablo Gonzalez-de-Santos  Angela Ribeiro  Cesar Fernandez-Quintanilla  Francisca Lopez-Granados  Michael Brandstoetter  Slobodanka Tomic  Stefania Pedrazzi  Andrea Peruzzi  Gonzalo Pajares  George Kaplanis  Manuel Perez-Ruiz  Constantino Valero  Jaime del Cerro  Marco Vieri  Gilles Rabatel  Benoit Debilde 《Precision Agriculture》2017,18(4):574-614

Feeding the growing global population requires an annual increase in food production. This requirement suggests an increase in the use of pesticides, which represents an unsustainable chemical load for the environment. To reduce pesticide input and preserve the environment while maintaining the necessary level of food production, the efficiency of relevant processes must be drastically improved. Within this context, this research strived to design, develop, test and assess a new generation of automatic and robotic systems for effective weed and pest control aimed at diminishing the use of agricultural chemical inputs, increasing crop quality and improving the health and safety of production operators. To achieve this overall objective, a fleet of heterogeneous ground and aerial robots was developed and equipped with innovative sensors, enhanced end-effectors and improved decision control algorithms to cover a large variety of agricultural situations. This article describes the scientific and technical objectives, challenges and outcomes achieved in three common crops.  相似文献   

Effect of restricted suckling on milk yield,composition and flow,udder health,and postpartum anoestrus in grazing Holstein cows     

Alejandro Mendoza  Daniel Cavestany  Gonzalo Roig  Julio Ariztia  Claudia Pereira  Alejandro La Manna  David A. Contreras  Carlos S. Galina 《Livestock Science》2010,127(1):60-66

The effect of restricted suckling on milk yield and composition, udder health, and postpartum anoestrus in dairy cows in pasture-based systems, was studied in 32 Holstein multiparous cows and their calves. At calving, each cow–calf pair was randomly assigned to one of two treatments: restricted suckling (RS) of the cows by her own or another calf, twice daily for 30 min or artificial rearing (AR) of the calves with milk obtained from the bulk tank, offered twice a day in buckets. Treatments were applied until week 8 after calving. The diet of the cows consisted of direct grazing in improved pastures, corn silage and a commercial concentrate which was offered at milking. Milk production and composition, udder health, body condition score of the cows, body weight and milk intake of the calves were measured weekly, and the first postpartum ovulation was determined three times a week by ovarian ultrasonography. Cows with RS management had a lower machine-milked milk yield (17.9 vs. 24.8 kg/d), a lower fat percentage (3.21 vs. 4.11%) and 4% fat-corrected milk yield (16.2 vs. 25.7 kg/d), and also a lower average milk flow (1.35 vs. 1.76 kg/min) than cows in the AR treatment. There was no effect of treatment on milk protein percentage or udder health as measured by milk electrical conductivity. The interval from calving to first postpartum ovulation was shorter in the AR cows than in the RS cows (18.5 vs. 21.8 days). The RS calves consumed more milk (7.2 vs. 5.4 kg/d), gained more body weight (0.813 vs. 0.656 kg/d), and had a higher body weight at weaning (84.3 vs. 73.3 kg) than AR calves. Restricted suckling of grazing dairy cows had a negative effect on machine-milked milk yield, fat percentage and 4% fat-corrected milk yield, but had no effect on udder health or on improved weight gain and body weight at weaning of the calves.  相似文献   

Syneresis rate of cow's, ewe's, and goat's curd. Effect of thermal treatment and ultrafiltration.     

M M Calvo  N A Espinoza 《Journal of agricultural and food chemistry》1999,47(3):883-886

The influences of ultrafiltration (UF), the intensity of heat treatment (70 degrees C for 5 or 30 min) applied to milk prior to UF processing, and species on the syneresis rate of curd from cow's, ewe's, and goat's milk were analyzed. The influence of the species was significant (P < 0.05) in the syneresis rate. The syneresis rate depended significantly on the intensity of the heat treatment applied before UF and the degree of concentration; these two parameters showed significant (P < 0.05) differences in the syneresis rate depending on the species studied. These results could indicate a possible difference in the structure of the curd formed. The differences in the curd structure could be due to the different relative composition of the retentates of the different species as well as the possible effect of the UF process on the physicochemical composition of milk.  相似文献   

Overfishing and the Common Fisheries Policy: (un)successful results from TAC regulation?     

Sebastián Villasante  María do Carme García‐Negro  Fernando González‐Laxe  Gonzalo Rodríguez Rodríguez 《Fish and Fisheries》2011,12(1):34-50

This paper combines official data from 1990–2007 for (i) the Total Allowable Catchs (TACs) recommended by International Council for the Exploration for the Sea (ICES) scientists and the proposed and approved TACs and (ii) biomass, recruitment, catches, fishing effort, and current exploitation rates for all marine populations subjected to TAC regulation. The differences between the fishing quotas and the scientific recommendations provided by the ICES were calculated to be 19% after the first CFP reform (1992–2001) and 21% after the second one (2002–2008). In some species, these differences showed a three‐fold increase, in particular those currently considered to be beyond the biological safety limits. Regarding the most important index of abundance, the results also indicate a biomass and recruitment reduction of ～75–85% of the stocks and 90% of catches, whereas the fishing mortality increased in 35% of stocks. In addition, of all populations analysed under TAC regulation, 20% presents an increase in the current exploitation rate, 17% did not show significant changes, and the remaining 63% presented a reduction between 1990 and 2007. These results could contribute to the recovery of stocks. However, following the methodology used by Worm et al. who reported that 6 out of the 10 (60%) marine ecosystems examined showed current exploitation rate values that were significantly higher than those that provide the maximum sustainable yield, this study demonstrates that 86% of the populations regulated by TACs present values higher than exploitation rates that give maximum sustainable yield, following an alarming pattern of exploitation.  相似文献   

Combining eight research areas to foster the uptake of ecosystem‐based management in fresh waters     

Simone D. Langhans  Sami Domisch  Stefano Balbi  Gonzalo Delacmara  Virgilio Hermoso  Mathias Kuemmerlen  Romina Martin  Javier Martínez‐Lpez  Peter Vermeiren  Ferdinando Villa  Sonja C. Jhnig 《水产资源保护:海洋与淡水生态系统》2019,29(7):1161-1173

Assessment of diet and temperature on the overall performance of Patagonian red octopus (Enteroctopus megalocyathus,Gould) paralarvae     

Ana Farías  Jorge Hernndez  Csar Torres  Viviana Espinoza  María Teresa Viana  Juan Carlos Navarro  Iker Uriarte 《Aquaculture Nutrition》2020,26(4):1275-1288

The limitation to sustain the Patagonian red octopus Enteroctopus megalocyathus aquaculture is the lack of an efficient diet to obtain high survival during the paralarvae stage. This work has studied the performance of paralarvae under different combinations of feeds and temperatures using a factorial design. The diets were based on various Artemia enrichments: (a) Nannochloropsis sp, (b) Ori‐gold (Skretting) and (c) LC60 (Phosphotek). The temperatures chosen were in accordance with those found in their environment: 10°C (winter), 12°C (spring–autumn) and 14°C (summer), by triplicate. The factorial combinations were tested in two experiments with paralarvae of different age: Exp 1, from newly hatched to 14 days after hatching (DAH), and Exp 2, from that point to 42 DAH. It was concluded that temperature was the primary variable affecting mortality, feed intake, relative weight condition index, morphometric variables and trypsin activity. The enriched Artemia diets had the main impact on the leucine‐aminopeptidase activity, and on the fatty acid contents, mainly 20:5n‐3 (EPA) and 22:6n‐3 (DHA). Paralarval growth was increased by temperature with only one diet and at a certain age. Nutritional requirements varied between early and late paralarvae, and the possibility of changing the diets according to the development age is discussed.  相似文献   

Genetic diversity and structure of wild and managed populations of Polaskia chende (Cactaceae) in the Tehuacán-Cuicatlán Valley,Central Mexico: insights from SSR and allozyme markers     

Gonzalo Contreras-Negrete  M. Eva Ruíz-Durán  Dánae Cabrera-Toledo  Alejandro Casas  Ofelia Vargas  Fabiola Parra 《Genetic Resources and Crop Evolution》2015,62(1):85-101

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Molecular characterization and genetic diversity of Prunus rootstocks     

Mariem Bouhadida  Ana María Casas  María José Gonzalo  Pere Arús  María Ángeles Moreno  Yolanda Gogorcena 《Scientia Horticulturae》2009

Twenty microsatellite primer pairs, previously developed in peach, were used to characterize and to explore genetic relationships among 44 clones, representing three groups of rootstocks defined as: (1) Peach-based rootstocks (Prunus dulcis × P. persica, P. persica × P. davidiana); (2) Myrobalan-Marianna plums (P. cerasifera and interspecific hybrids having P. cerasifera as a parent); and (3) Slow growing plums (P. insititia, P. domestica, and P. domestica × P. spinosa). Eighteen SSR markers, from the 20 initially used, were able to amplify polymorphic products for the Peach-based rootstocks and 13 common markers gave also polymorphism for the Myrobalan-Marianna and Slow growing plums groups. The Dice coefficient of similarity was calculated between all pairs of accessions and their genetic similarity represented by a principal coordinate analysis. The genetic diversity detected among the 44 clones studied divided them in three groups, which are in agreement with their current taxonomic classification and their morphological characteristics. A set of three microsatellites (BPPCT001, CPPCT022 and UDP98-407) can distinguish between all the clones analyzed. The analysis within groups reveal another two sets of three SSR to distinguish between the clones from the Peach based rootstocks and the Myrobalan-Marianna plums, respectively, and only a single SSR is needed to distinguish within the clones from the Slow growing plums group. These results demonstrate the high potential of the SSR analysis for peach rootstock identification and studies of diversity in Prunus species.  相似文献