Cyperus esculentus - differences in growth and tuber production between cultivated and wild forms

Cyperus esculentus (yellow nutsedge) belongs to the world most important weeds on arable land. This species is classified as an invasive one in Central and North-western Europe. It is not yet present as a weed in the Czech Republic, but its occurrence in neighbouring countries and its ability to survive winters in this region must be taken into account. A cultivated form of C. esculentus, known as Chufa or Tiger nuts, is occasionally grown in home gardens as a crop for its edible tubers. In pot experiments we tested the growth of both forms, weedy and cultivated one. Weight of both fresh and dry biomass of plant parts (leaves, roots, rhizomes, tubers, inflorescences) was measured in monthly intervals from May till September 2012. Results show that there were no significant differences in leaf and root biomass. The weight of rhizomes was approximately 50-80 times higher in the wild form. Number of tubers was also higher in the wild form (max. 1118 pcs; crop max. 342 pcs in single pot), but the total weight of tubers was not significantly different. The cultivated form did not produce inflorescences at all, the wild form produced in average 13 inflorescences per plot. Based on our results we can state that growing of the cultivated form does not pose any risk – plants do not show intensive vegetative spread and do not produce inflorescences so crossing with the weedy form is not possible. The wild form can produce high amounts of rhizomes and tubers and is able to produce flowers under our conditions. That makes it a potentially dangerous weed in warmer regions of the Czech Republic.Keywords: Biomass production, crop, CYPES, invasive weed, yellow nutsedgeCyperus esculentus - Unterschiede in Wachstum und Knollenbildung zwischen Kultur- und WildformenZusammenfassungCyperus esculentus (Erdmandelgras) gehört zu den weltweit wichtigsten Unkräutern auf Ackerflächen. Diese Art ist klassifiziert als invasiv in Zentral- und Nordwesteuropa. Die Wildform kommt in der Tschechischen Republik nicht vor, aber in den Nachbarländern. Ihre Fähigkeit, die Winter in dieser Region zu überleben, muss berücksichtigt werden. Die Zuchtform von C. esculentus, als Chufa oder Tigernuss bekannt, wird gelegentlich in Hausgärten als Kulturpflanze wegen ihrer essbaren Knollen angebaut. In Gefäßversuchen haben wir das Wachstum der beiden Formen, Wild- und Kulturpflanze, getestet. Frisch- und Trockenmasse von Pflanzenteilen (Blätter, Wurzeln, Rhizome, Knollen, Blütenstände) wurden in monatlichen Abständen von Mai bis September 2012 gemessen. Die Ergebnisse zeigen keine signifikanten Unterschiede in der Blatt- und Wurzelbiomasse. Das Gewicht der Rhizome war bei der Wildform etwa 50- bis 80mal höher. Die Anzahl der Knollen war in der Wildform ebenfalls höher (max. 1.118 Stück/Gefäß) als bei der Zuchtform (max. 342 Stück/Gefäß). Das Gesamtgewicht der Knollen war nicht signifikant verschieden. Die Zuchtform bildete keine Blütenstände; die Wildform bildete durchschnittlich 13 Blütenstände pro Gefäß. Basierend auf unseren Ergebnissen können wir feststellen, dass der Anbau der Zuchtform keine Gefahr ist, denn die Pflanzen zeigen keine intensive vegetative Ausbreitung und bilden keine Blütenstände, sodass die Kreuzung mit der Wildform nicht möglich ist. Die Wildform bildet große Mengen an Rhizomen und Knollen und ist fähig, unter unseren Bedingungen zu blühen. Das macht dieses Unkraut in wärmeren Regionen der Tschechischen Republik potenziell gefährlich.Stichwörter: Biomasse-Produktion, CYPES, Erdmandelgras, invasives Unkraut, Knollenbildun

Verification of a machine learning model for weed detection in maize (Zea mays) using infrared imaging

The potential of the framework of precision agriculture points towards the emergence of site-specific weed control. In light of the phenomena, the search for a cost-effective approach can help the discipline to accelerate the practical implementation. The paper presents a near-infrared data-driven machine learning model for real-time weed detection in wide-row cultivated maize (Zea mays) fields. The basis of the model is a dataset of 5 120 objects including 18 species of weeds significant in the context of wide-row crop production in the Czech Republic. The custom model was subsequently compared with a state-of-the-art machine learning tool You only look once (version 3). The custom model achieved 94.5 % identification accuracy while highlighting the practical limitations of the dataset

A GIS TOOL TO EVALUATE THE SPATIAL EVOLUTION OF HYDRO-THERMIC FEATURES DURING GROWING SEASON OF VEGETABLE CROPS IN ELBE RIVER LOWLAND (POLABI)

A GIS tool to evaluate the spatial evolution of hydro-thermic features during growing season of vegetable crops in Elbe River lowland (Polabi). This article presents the results of the first study on combined mezoclimatological, microclimatological and topographical tools for evaluating precision farming in the growth of vegetable crops in the Elbe River lowland (Polabi) region from the Czech Republic. We assess the variability of basically climatological characteristics in relation to topographic characteristics at the regional (Polabi) and local (agricultural farm) scales. At regional scale, interpolation approach is based on local linear regression and universal kriging interpolation. At local scale, two conventional interpolation methods, spline and local ordinary kriging with a Gaussian model variance across the fields, were applied. The local spline interpolators have been used in developing digital elevation models (DEMs) and to determine the slope angle inclination of vegetable fields. The DEMs of the vegetable crops fields was developed at a 10 m x 10 m resolution based on elevation data collected in the field by a hand-held RTK- Global Positioning System receiver. This tool allowed the distinction of microclimatic conditions that produce altitude-slope-related patterns of the spatial-temporal distribution of the basic meteorological elements during growing season of vegetable crops. The effect of slope on diurnal extreme temperatures in the vegetable cropped field conditions was more pronounced than that of elevation. Accordingly to developed maps, the warmest and longest duration of sunshine, and the least precipitation totals during growing season occurred in the middle part of Polabi

Expert system for decision making about using of fungicides and zoocides in permanent cultures and vegetables and using of herbicides in field crops:certified methodology

Basic principles of expert system for decision making about using of fungicides and zoocides in permanent cultures and vegetables and using of herbicides in field crops including vegetable are described in methodology. Procedure for decision making about using of pesticides is based on using of multidimensional economic thresholds, mainly for pest and weeds, and on analysis of economic parameters and evaluation of negative impact of pesticides on the environment. Methods of development of damage curves and the model for determination of multidimensional economic threshold for pests and weeds are described. Methods for determination of environmental impact for active substances of herbicides, zoocides and fungicides are described. Principles of model of degradation of residues of pesticides in fruit and vegetable are described and verified on case studies of herbicides in vegetable and zoocides and fungicides in fruit and vegetable

Comparison of active leveling and pre-calibrating/substitution method for radiated immunity testing of large equipment

Radiated susceptibility tests have originally been performed using the so-called leveling method: a field strength sensor is put in front or on top of the equipment under test and the power towards the antenna is changed until the required level is achieved. Since computers became available for controlling test equipment the pre-calibration, or substitution, method became more popular. From a metrology point of view this is also a standard method but the leveling method is still preferred in some standards. The advantages and disadvantages of the methods are described in terms of the testing of very large equipment. Measurements were carried out with large and small equipment and the result shows that the methods are applicable for different purposes; Active leveling is more suitable for small EUT in closer distance while the pre-calibration is the established and preferred method for large equipment

Proficiency testing for conducted immunity with a new round robin test device

Last year, a new round robin test device was proposed for inter-laboratory comparisons in conducted immunity testing according to IEC 61000-4-6[1]. The device has recently been successfully evaluated among all EMRP Project partners. The device is able to confirm or to deny the testing capability of a laboratory by recording a full set of parameters. The device is now ready for deployment as the first commercial proficiency testing device for conducted immunity