Analysis, assessment, and improvement of fertilizer distribution in pressure irrigation systems

[EN] The transformation of traditional irrigation systems into pressure irrigation networks allows water users associations to use central fertigation systems. For efficient fertigation management, however, it is essential to obtain uniform distribution of the injected fertilizer through the system and to understand the hydraulic processes that take place in the central fertigation system. This will allow users to implement strategies that improve fertilizer distribution. In this work we develop a new methodology to improve fertilizer distribution uniformity and apply it to a case study. The results show how fertilizer distribution can be improved by means of proper scheduling of irrigation deliveries. The best results are obtained when fertigating sectors operate without non-fertigating sectors and there are not intermediate irrigations without fertilizer, achieving an improvement of the fertilizer distribution of 10.5%. In addition, this work highlights the difficulties of obtaining uniform distribution of fertilizer in a centralized irrigation system when there are users that do not want to make use of it.Jiménez Bello, MA.; Martínez Alzamora, F.; Bou Soler, V.; Bartolín Ayala, HJ. (2010). Analysis, assessment, and improvement of fertilizer distribution in pressure irrigation systems. Irrigation Science. 29(1):45-53. doi:10.1007/s00271-010-0215-7S4553291Arviza J y Balbastre I (2002a) “Redes de Riego a presión. Consideraciones sobre la fertirrigación colectiva”. Revista Levante Agrícola nº 359. 1º trimestre. Págs. 70–81. Ediciones y promociones LAV SL. ValenciaArviza J y Balbastre I (2002b) “Redes de Riego a presión. Consideraciones sobre la fertirrigación colectiva. Parte II”. Revista Levante Agrícola nº 360. 2º trimestre. Págs. 133–139. Ediciones y promociones LAV SL. ValenciaArviza J, Martínez F, y Balbastre I (2002) Análisis de la distribución de fertilizantes en sistemas colectivos de riego a presión. XX Congreso Nacional de Riegos. Ciudad Real. EspañaBracy RP, Parish RL, Rosendale RM (2003) Fertigation uniformity affected by injector type. Horttechnology 13:103–105Goldberg DE (1989) Genetic algorithms in search, optimization and machine learning. Addison-Wesley, ReadingJiménez MA, Martínez F, Arviza J, Manzano J (2006) Herramientas para el uso racional del agua con el apoyo de un GIS (HuraGIS). XXIV. Congreso nacional de riegos. Lugo (Spain). (Jun 2006)Jiménez MA, Martínez F, Arviza J, Manzano J (2008) Optimización de la sectorización de redes de riego a presión mediante algoritmos genéticos XXVI. Congreso nacional de riegos. Huesca. (Jun 2008)Jiusheng L, Yibin M, Bei L (2007) Field evaluation of fertigation uniformity as affected by injector type and manufacturing variability of emitters. Irrigation Sci 25:117–125Kalyanmoy D (2001) Multi-objective optimization using evolutionary algorithms. Willey, EnglandRossman LA (2000) Epanet 2, Users Manual. Water Supply and Water Resources Division. National Risk Management Research Laboratory, CincinnatiSavic D, Walters G (1997) Genetic algorithms for least-cost design of water distribution networks. J Water Resour Plann Manag 123(2):67–77 (March/April 1997

Irrigation management in poplar (Populus spp.) plantations: A review

15 páginas.- 5 figuras.- 1 tabla.- 134 referencias.- Supplementary data to this article can be found online at https://doi.org/10.1016/j.foreco.2021.119330Poplar (Populus spp.) is widely planted around the world and has been closely linked to human beings since ancient times due to its multiple beneficial utilizations both for the environment and society. As one of the fastest-growing tree species in temperate zones, the high growth rate of poplar is associated with its high waterdemand, which makes it vulnerable to water deficits. To maintain and improve the productivity and quality of poplar plantations, by alleviating the impact of soil water deficit on tree growth and health, irrigation has been long applied as an essential cultivation practice for poplar plantations around the world. However, both fundamentals for irrigation and technology innovations are limited by the lack of critical knowledge on the irrigation management practices in poplar plantations. In this work, data and information collected from questionnaires, literature, and a survey around the world, were used to investigate the current situation of irrigation management in poplar plantations. We present a summary of the currently applied irrigation regimes for poplars. Then, with the help of the literature and a global dataset of poplar growth compiled with data from 27 sites in five countries, we thoroughly analyzed and reviewed the main effects of irrigation on poplar plantations. Finally, the profitability of irrigation in poplar plantations is discussed. We conclude with some existing problems and future research directions for irrigation management of poplars. In addition to providing directions for the sustainable management of poplar plantations in global water-limited regions, this work also provides a reference for the water management in plantations of other tree species.This research was jointly supported by the National Natural Science Foundation of China (31872702) and the National Key Research and Development Program of China (2016YFD0600403) .Peer reviewe

AI is a viable alternative to high throughput screening: a 318-target study

: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

WTC2005-64002 Study on Biodegradable Lubricants: Improvement in oxidation stability of vegetable oils

Abstract To improve the oxidation stability of vegetable oil, several chemical reactions such as transesterification, polymerization and epoxidation were used to reduce the content of unsaturated bonds in their molecules. The results of oxidation test indicate that epoxidation is an available method to improve the oxidation stabilities of vegetable oils. The efficiencies of antioxidants used for protection of rapeseed oil from oxidation were studied using PDSC, and the active energies of oil samples were calculated by using Arrhenius equation

Bidirectional Terahertz Vortex Beam Regulator

Most of the reported vortex beam generators with orbital angular momentum (OAM) in the terahertz region only operate in either the reflection mode or the transmission mode, which greatly limits the integration and application in terahertz technology systems. Herein, we propose a full-space vortex beam regulator at two different frequencies. By changing the VO2 phase transition state, the transmission and reflection mode OAM beams can be flexibly controlled by a single metasurface. For the transmission mode, the proposed structure realizes an OAM beam at the topological charges of l = 1 and 2 at 0.6 THz and 1.4 THz. For the reflection mode, our structure generates an OAM beam at the topological charges of l = 1 and 2 at 0.9 THz and 1.5 THz. Based on the superposition theorem and convolution operation principle, the regulation of an OAM vortex beam with a specific deflection angle and a symmetrical deflection OAM vortex beam are realized. The designed metasurface integrates multiple transmitted and reflected vortex beam functions in full space and has potential application in different terahertz systems