scholarly journals Weather, cultivar and density-dependent processes influence on aphid in alfalfa

Bragantia ◽  
2007 ◽  
Vol 66 (2) ◽  
pp. 285-290 ◽  
Author(s):  
Alexandre de Almeida e Silva ◽  
Elenice Mouro Varanda ◽  
Joaquim Bartolomeu Rassini

It is important to understand the effects of weather, insect density and plant cultivar on insect abundance to predict and prevent crop production loss. The present work investigated the influence of such factors on aphid in alfalfa during one year (short term). Data was collected from September/1997 to August/1998 at Canchin Farm (CCPSE-EMBRAPA), São Carlos, State of São Paulo, Brazil. Weather conditions had, in general, little effect on the variation of aphid populations, but Therioaphis maculata abundance was negatively correlated to humidity. Moreover, high maximum temperatures and low levels of rainfall possible favored T. maculata high abundance on Crioula and P3 cultivars. Therefore, appropriate management of this species is required during hot and dry periods. Population variation of Acyrthosiphon spp., T. maculata and Aphis craccivora seems to be regulated by density dependent processes. Resistant cultivar CUF 101 had a lower abundance of T. maculata and A. craccivora and a narrower population variation than the other cultivars and may reduce their abundance on field. Long-term studies on population dynamics including the effect of climatic conditions and density-dependent factors on plant quality will contribute to pest management in alfalfa fields.

Author(s):  
J. Schachtschneider ◽  
C. Brenner

Abstract. The development of automated and autonomous vehicles requires highly accurate long-term maps of the environment. Urban areas contain a large number of dynamic objects which change over time. Since a permanent observation of the environment is impossible and there will always be a first time visit of an unknown or changed area, a map of an urban environment needs to model such dynamics.In this work, we use LiDAR point clouds from a large long term measurement campaign to investigate temporal changes. The data set was recorded along a 20 km route in Hannover, Germany with a Mobile Mapping System over a period of one year in bi-weekly measurements. The data set covers a variety of different urban objects and areas, weather conditions and seasons. Based on this data set, we show how scene and seasonal effects influence the measurement likelihood, and that multi-temporal maps lead to the best positioning results.


2010 ◽  
Vol 58 (Supplement 1) ◽  
pp. 75-81 ◽  
Author(s):  
M. Birkás

The Crop Production Institute of Szent István University carried out soil quality trials in the region of Gödöllő between 1977 and 2002, followed by similar experiments near the town of Hatvan since 2002. Soil quality factors that can be improved by tillage include the looseness of the root zone, the depth of the loosened layer, the duration of the loosened state, the thickness of the compact layer impeding water transport, the soil structure, the level of surface protection, the water intake/water loss balance, the organic material balance and earthworm activity. Optimising these factors can help reduce climate stress, so that extreme weather conditions do not undermine the reliability of farming. Most of the tillage methods elaborated on the basis of the findings of the trials, with the aim of alleviating climate stress, differ from conventional recommendations.


2020 ◽  
Vol 12 (9) ◽  
pp. 3858 ◽  
Author(s):  
Magda Sibley ◽  
Antonio Peña-García

This paper presents the first comparative study of its type of the performance of light pipes with different types of apertures: a flat glass versus a bohemian crystal dome. Measurements were taken at 20-minute intervals over a period of one year in the bathrooms of two newly built identical houses of the same orientation located in Manchester, UK. The comparative analysis of the data collected for both light pipes types reveals that the crystal domed aperture consistently outperforms the flat glass one. Furthermore, the difference in the recorded horizontal illuminance is most marked during the winter months and at the end of the one-year experiment, indicating that the crystal dome has better performance for low incident winter light and higher resistance for the long term effect of weathering and pollution. This study provides strong evidence based on long term real measurements. Such evidence informs architects’ decisions when weighing up the aesthetic considerations of a flat glass aperture versus the higher illumination levels afforded by a crystal dome aperture with higher resistance to weathering and pollution.


The Holocene ◽  
2016 ◽  
Vol 27 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Heli Huhtamaa ◽  
Samuli Helama

Lack of documentation on past harvest fluctuations limits the exploration of long-term trends in crop production and agricultural adaptation strategies. A long-term perspective is needed, however, to understand the wide spectrum of potential human responses to environment and climate change. Therefore, we used tree-ring density series as proxy data to reconstruct climate-mediated yield ratio (harvested grain in relation to sown) in central and northern Finland over the period ad 760–2000. The reconstruction explains 50% of the variance in recorded yield ratio variability over the calibration period (ad 1866–1921). The reconstruction illustrated several intervals of increased and reduced yield ratio over the past 13 centuries. The long-term development of the agricultural prerequisites is characterized by distinct intervals defined statistically as ad 760–1106 (highest yield ratios), 1107–1451, 1452–1694, 1695–1911 (lowest yield ratios) and 1912 onwards. The results provide insight into the establishment and development of crop cultivation in the agricultural margin. The reconstruction suggests that continuous crop cultivation was established in the study region during a favourable period of climatic conditions supporting high yields. Thereafter, the climate-mediated yield ratio declined in the long run until the turn of the 20th century. Periods of agricultural transformations, those previously demonstrated in pollen data and historical documents, followed the onsets of the low yield ratio phases indicated by our reconstruction. Thus, we suggest that ever since the establishment of crop cultivation, climate can be considered as an important factor contributing to the development of the agricultural history in the north.


2021 ◽  
Author(s):  
Sabina Thaler ◽  
Josef Eitzinger ◽  
Gerhard Kubu

<p>Weather-related risks can affect crop growth and yield potentials directly (e.g. heat, frost, drought) and indirectly (e.g. through biotic factors such as pests). Due to climate change, severe shifts of cropping risks may occur, where farmers need to adapt effectively and in time to increase the resilience of existing cropping systems. For example, since the early 21st century, Europe has experienced a series of exceptionally dry and warmer than usual weather conditions (2003, 2012, 2013, 2015, 2018) which led to severe droughts with devastating impacts in agriculture on crop yields and pasture productivity.</p><p>Austria has experienced above-average warming in the period since 1880. While the global average surface temperature has increased by almost 1°C, the warming in Austria during this period was nearly 2°C. Higher temperatures, changing precipitation patterns and more severe and frequent extreme weather events will significantly affect weather-sensitive sectors, especially agriculture. Therefore, the development of sound adaptation and mitigation strategies towards a "climate-intelligent agriculture" is crucial to improve the resilience of agricultural systems to climate change and increased climate variability. Within the project AGROFORECAST a set of weather-related risk indicators and tailored recommendations for optimizing crop management options are developed and tested for various forecast or prediction lead times (short term management: 10 days - 6 months; long term strategic planning: climate scenarios) to better inform farmers of upcoming weather and climate challenges.</p><p>Here we present trends of various types of long-term weather-related impacts on Austrian crop production under past (1980-2020) and future periods (2035-2065). For that purpose, agro-climatic risk indicators and crop production indicators are determined in selected case study regions with the help of models. We use for the past period Austrian gridded weather data set (INCA) as well as different regionalized climate scenarios of the Austrian Climate Change Projections ÖKS15. The calculation of the agro-climatic indicators is carried out by the existing AGRICLIM model and the GIS-based ARIS software, which was developed for estimating the impact of adverse weather conditions on crops. The crop growth model AQUACROP is used for analysing soil-crop water balance parameters, crop yields and future crop water demand.</p><p>Depending on the climatic region, a more or less clear shift in the various agro-climatic indices can be expected towards 2050, e.g. the number of "heat-stress-days" for winter wheat increases significantly in eastern Austria. Furthermore, a decreasing trend in maize yield is simulated, whereas a mean increase in yield of spring barley and winter wheat can be expected under selected scenarios. Other agro-climatic risk indicators analysed include pest algorithms, risks from frost occurrence, overwintering conditions, climatic crop growing conditions, field workability and others, which can add additional impacts on crop yield variability, not considered by crop models.</p>


2021 ◽  
Vol 258 ◽  
pp. 04024
Author(s):  
Shavkat Durkhodjaev ◽  
Sohibjon Islamov ◽  
Tulganoy Kenjaeva ◽  
Abdulaziz Tojiboyev

In this article, the results of research on the cultivation of patty pan squash in the climatic conditions of Uzbekistan, Planting for different periods and its growth, development, yield, as well as the impact of weather conditions were presented. Squash is a one-year plant of the family of zucchini, mainly shrub, rarely found in the form of a whip. The results showed that average yield of “White-13” control was 16 tons/ha, and it was 17 tons/ha in “Solnyshko”. Furthermore, “NLO White” and “Umberall” had a high yield compared to the other varieties and hybrids, accounted for 15 tons/ha and 15.1 tons/ha, respectively. The highest average temperature during seed germination was found in 16 august, which was 30.3°C, whereas the lowest average temperature was 18.6°C in 1st April. The results showed that 4 days were required to reach 10% of seed germination in the period April 16 and May 1, however, 10% of seed germination in July 1 and 16th took 6 days. Furthermore, the least days for 75% of seed, germination was observed in the period of May 1, accounted for 8 days, and the rest of the period was the same.


Author(s):  
Gennady V. Menzhulin ◽  
Sergey P. Savvateyev

The climate of a region is a representation of long-term weather conditions that prevail there. Over the millions of years of the existence of the atmosphere on the earth, the climate has changed all the time; ice ages have come and gone, and this has been the result of natural causes. Recently (on geological time scales) the human population has expanded—from half a billion in 1600, to 1 billion in 1800, to almost 3 billion in 1940, and it now stands at about 6 billion. The climate may well now be influenced not only as before by natural events but also by human activities. For example, we are producing vast amounts of carbon dioxide by burning fossil fuels, and this is causing the temperature of the earth to rise significantly. If we argue that we should control our activities to preserve this planet as a habitable environment for future generations, we need to have some scientific knowledge of the effects of our present activities on climate. In recent years the evidence has been accumulating that on the time scale of decades there is global warming (i.e., the global annual mean surface temperature is increasing). There is also evidence accumulating that part of this increase is a consequence of human activities. The evidence is largely statistical. Within this trend there are bound to be temporal fluctuations and spatial variations. Moreover, in addition to the increase in temperature, it is reasonable to assume that there is, overall, an increase in evaporation of water from the surface of the earth and that there will be a consequent increase in precipitation. But within this overall scenario there are bound to be local variations; some areas may experience more precipitation, but some areas may experience less precipitation. The effect of climate change on the proneness to drought is therefore not uniform but can be expected to vary from place to place. Therefore, whether one is concerned with considering the relation between climate and proneness to drought from the historical evidence or whether one is trying to use models to predict the effect of future climatic conditions, it is necessary to consider the local spatial variations.


2021 ◽  
Vol 7 ◽  
pp. 133-150
Author(s):  
Jiban Shrestha ◽  
Subash Subedi ◽  
Krishna Prasad Timsina ◽  
Sudeep Subedi ◽  
Meena Pandey ◽  
...  

Sustainable intensification of agriculture is a good approach for reducing the yield gap without exacerbating the current condition of the environmental components, which is a big challenge for agriculture in the modern world. This review provides a summary of the role and approaches of sustainable intensification in agriculture which offer ways to increase crop production and create long-term sustainability in agriculture production. The current demand for food has continued to rise as a result of the world's rapidly increasing population. In order to increase crop/food production, agricultural systems should be intensified by more sustainable practices, as well as by reforming existing production systems/techniques and diversifying them into newer and more profitable enterprises. Despite the heavy use of inputs, farmers have recently been unable to achieve optimal crop yields. The judicious use of agricultural inputs, combined with improved management techniques, is important for advancing sustainable intensification. New scientific techniques in agronomic practices, as well as improved farm mechanization, are helping to boost resource use efficiency in sustainable crop production. The sustainable agricultural intensification is necessary to increase the agricultural productivity under the changing and adverse climatic conditions while maintaining healthy production practices.


Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6921
Author(s):  
Sebastian Pater

A hybrid photovoltaic-thermal collector (PV-T) with the capability to produce thermal energy and electrical energy simultaneously has attracted the attention of researchers, especially in terms of improving PV-T performance. This study analyses the work of four model installations with PV-T and other devices built in the transient systems simulation program. The novelty of this article lies in a long-term approach to the operation of PV-T panels under selected climatic conditions. Influence of the installation’s configuration on the obtained temperatures of solar cells, and, in consequence, on electric power generated by PV-T and the amount of heat produced during one year in a selected location is presented. Among others, the impact of the temperature coefficient of photovoltaic cells for long-term PV-T operation was analyzed in the paper. The results showed that the type of cell used may decrease the yearly electric energy production from PV-T even by 7%. On the other hand, intensification of the process of heat reception from PV-T using a heat pump increased this production by 6% in relation to the base model. The obtained research results indicate possible methods for improving the effectiveness of PV-T operation in a long-term aspect.


2019 ◽  
Vol 41 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Pyotr Kovalenko ◽  
Anatoliy Rokochinskiy ◽  
Jerzy Jeznach ◽  
Roman Koptyuk ◽  
Pavlo Volk ◽  
...  

Abstract The analysis of the current state of weather and climatic conditions and evaluation of their predicted changes for immediate and distant prospect in the drained areas of Ukrainian Polissia region was carried out in the article. The main trends in changes of meteorological characteristics and their possible effect on the conditions of functioning water management and ameliorative objects and complexes as well as on the natural and ameliorative state of drained areas were identified. The research uses a method of predictive-simulation modelling with used predictive assessment models of normalized distribution of the basic meteorological characteristics in the long-term and one-year vegetation context. According to the results of the research it was established that, for today a high variability in meteorological characteristics can lead to the significant deterioration of operation conditions of water management and ameliorative objects and units, as well as natural and ameliorative conditions of drained lands in Polissia region as a whole. Core measures regarding the adaptive potential enhancement and development in the region under the conditions of climate change were examined.


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