LV EN RU DE FR

Weed Science I

Course developers

Replaced course

LauZ5125 [GLAU5128] Weed Science I

Course abstract

Students of master studies become more profound to biological properties of weeds species diversity. Obtain the knowledge about the plant life-relating factors, prognosis of changes by modelling Technologies of crop production. Evolution of weed control. Using of biological individuality of weeds for weed control. Weeds in the agrophytocenosis. Valuation criteria of agroeconomical efficiency of weed control, different weed control technologies. The aim of the study course is to prepare knowledgeable specialists in herbology.

Learning outcomes and their assessment

1. Students obtain the more profound knowledge about scientific basics of weed biology, species diversity and weed control. Students to know put into practice the biological properties of weeds for weed control.
2. Students acquire skills to applied and compare different criteria of valuation of economical efficiency of weed control, different weed control technologies.
3. In the result students are competent to direct production or advisory work, to carry out investigations self-dependently, employing knowledge in weed biology and control, to study and analysis scientific publications.

Course Content(Calendar)

1. Study course structure, expected results, assignments, study literature – 1 h
2. The concept of weed science as a science. Definitions of weeds. Biology and ecology of weeds – 2 h
3. The importance of weeds in agrocenosis. Classification of weeds: botanical, biological, economic-biological – 1 h
4. Weeds as environmental indicators – 1 h
Test 1 (2 - 4-point questions) – 1 h
5. Weed development cycles and reproductive biology: generative, vegetative. Connection with weed control – 1 h
6. Dormancy period of weed seeds, its duration. Periodicity of weed germination. Characterization of crops and soil weediness in Latvia – 2 h
7. Weediness of the soil or seed banks, their research methodology – 2 h
8. Invasive weed species and their invaders, relationship with the surrounding environment –
2 h
9. Relationship between crops and weeds: concept of competition, determinants of competitiveness – 1 h
10. Allelopathy. Studies on the allelopathic properties of weeds and crops – 2 h
11. Harmfulness of weeds. Thresholds of harmfulness of different weed species – 1 h
12. Economic importance of weeds – 2 h
Test 2 (5 - 12-point questions) – 1 h
13. Weed control measures: direct and indirect, principles of their application. Direct weed control measures: mechanical, chemical, biological, physical –1 h
14. Mechanical weed control: principles, applications and methods. Mechanical control of weeds in relation to biological groups of weeds – 2 h
15. Impact of traditional and reduced tillage systems on seed weediness – 1 h
16. Biological control of weeds: biological agents – 1 h
17. Effect of crop rotation or crop sequence on seed weediness –1 h
18. Weed resistance – 1 h
Test 3 (13 - 18-point questions) – 1 h

Practical works/ seminars
1. The models of economical threshold of different weed groups – 2 h
2. The effectiveness of agroeconomical criteria of weed control estimation – 2 h
3. Characteristics of soil and crop weediness – 2 h
4. Seminar. Crop weediness of field crops in Latvia – 2 h
5. The potential – 2 h
6. The investigation methods of weed population – 2 h
7. Development of weed control in future – 2 h
8. Seminar. Integrated weed management systems – 2 h

Laboratory works
1. Identification of weed seeds in soil and crop yield (tutorial) – 4 h
2. Database of weeds – 2 h
3. Identification of weed seedlings by the shape (tutorial) – 2 h
4. Crop weediness analyses by variance method – 2 h
5. Processing of the data obtained in the trials, creation of a database on weeds with the help of computer equipment – 2 h

Requirements for awarding credit points

The written examination.
The assignment for the test includes: theoretical questions covered during the semester.
All tests and tutorials of laboratory works should have a positive evaluation and have also submitted a report, the topic of which has been agreed with the head of the study course.
Before to pass an examination must be presented report.

Description of the organization and tasks of students’ independent work

Students have to prepare two homework’s about determine theme and present them (homework’s tasks to students give the head of the study course).
Homework No 1: the task must provide a detailed description of 5 weed species which representing a specific biological group (at least 10 pages, an electronic version).
Homework No 2: the task must include mathematical calculations of data (number of weeds and crop yield) analysis of their relationship (at least 5 pages, an electronic version).
The report should be written using the results of research on the chosen topic. Scientific articles have been published in international journals, international conference proceedings or monographs. The volume of the report at least 14 pages, an electronic version and presented, reporting time up to 15 min.
Preparation for tests.
Literary studies.

Criteria for Evaluating Learning Outcomes

The assessment of three study course examination is cumulative. It is made up of the grades of the examination tests during the semester and tutorials of laboratory works.
The grade is successful if at least 50% of the questions of tests or the examination are correct.
Students who have at least „7” are not required to write a theoretical part of the examination; their grade for this part is made up of an arithmetic mean of grades in tests during the semester and grade of tutorials of laboratory works.

Compulsory reading

1. Kroģere R. (2021). Laukkopības praktikums. II daļa Tīruma nezāles. Jelgava: LLU, 37 lpp.
2. Lapiņš D., Kažotnieks J. (2000). Laukkopība. Ozolnieki, LLKC, 247 lpp.
3. Hanf M. (1983). The arable weeds of Europe with their seedlings and seeds. BASF Aktiengesellschaft, Ludwigshafen. 494 p.
4. Korres N. E., Burgos N. R., Duke S. O. (2021). Weed Control Sustainability, Hazards, and Risks in Cropping Systems Worldwide. CRP Press. 680 p.
5. Rao V. S. (2020). Principles of Weed Science. CBS Publishers and Distributors. 580 p.
6. Aldrich R. J., Kremer R. J. (1997). Principles in Weed Management. Iowa State University Press. 425 p.
7. Handbook of Weed Management Systems. (1995). Edited by Albert E. Smith. Marcel Dekker, Inc. 741 p.
8. Hanus H., Heyland K. U., Keller E. (1997). Grundlagen des Pflanzenbaues. 800 s.
9. Radosevich S., Holt J., Ghersa C. (1997). Weed Ecology: Implications for Management. 589 p.
10. Weed Control Handbook: Principles. (1990). Ed. by R. J. Hance, K. Holly. Blackwell Scientific Publications: Oxford. 553 p.
11. Weed Research. (2017). Expanding Horizons. Edited by Hatcher P. E., Fround-Williams R. J. Willey. 432 p.

Further reading

1. Hakansson S. (2003). Weeds and Weed Management on Arable Land: An Ecological Approach. CABI Publishing. 288 p.
2. Hant M. (1983). The Arable Weeds of Europe. BASF U.K. 494 p.
3. Modern Crop Protection Compounds. (2012). Vol. 1: Herbicides. Edited by W. Kramer, U. Schirmer, P. Jaschke, M. Witschel. Willey VCH Verlag GmbH & Co. KcaA. 534 p.
4. Nezāļu, to grupu un augu aizsardzības tehnikas terminoloģijas vārdnīca (1997). A. Lejiņš,
A. Rasiņš, J. Āboliņš, G. Gavrilova, D. Lapiņš, J. Ozols, E. Vimba. Skrīveri: Latvijas Valsts Zemkopības zinātniskās pētniecības institūts „AGRA”. 300 lpp.
5. Priedītis N. (2014). Latvijas augi. Rīga: Gandrs.
888 lpp.

Periodicals and other sources

Zinātnisko žurnālu un konferenču krājumu raksti: Weed Biology and Management. Weed Research. Weed Technology. Agronomy Journal. Weed Biology and Management. European Weed Research Society (EWRS). Wiley Online Library.

Notes

Elective (Part B) study course. Academic masterʼs study program “Agriculture”.