Are we making progress in mechanical weed control research?

This study investigates whether researchers’ perceptions of good research are in agreement with current research practice as reflected in Weed Research. A high degree of agreement is assumed to indicate progress. The instrument used to survey researchers perceptions was a questionnaire consisting of 28 items related to (1) research methodologies, (2) research priorities, (3) quality of publications, (4) future developments in technology and agriculture and (5) general attitudes to alternative and conventional agriculture. Questions about gender and personal research engagement were also laid down in the questionnaire. The questionnaire was sent out by e-mail to about 140 researchers on the mailing list of the EWRS – Physical and Cultural Weed Control Group and 60 questionnaires were completed and returned. An analysis of all Weed Research publications in the period 1998-2003 investigated current research practices. The questionnaire showed that researchers in the working group are not specialized. Of the respondents, only 4 researchers (7%) used 50% or more of their research hours on mechanical weed control but a total of 44 researchers (73%) were active within this area. Views on research and agriculture varied significantly within the group and two counter paradigms were identified often refereed to as alternative and dominant. The alternative paradigm was connected with organic farming and the dominant paradigm was connected with conventional agriculture. Alternative paradigmatic positions prevailed among the respondents although strong dominant positions were also represented. Females (N=15) held more alternative positions than males (P < 0.01) and researchers engaged in herbicide technology (N=13) held more dominant positions than the rest (P < 0.05). By using an alternative-dominant scale, it was evident that respondents’ perceptions of good research was linked to basic values and beliefs that determine the overall understanding of how agriculture works and should be developed. Alternative perceptions of good research, however, seemed to be inconsistent with the current research practice as reflected in Weed Research. Consistency between ideals and reality should result in (1) more multidisciplinary studies to facilitate broader perspectives on weed control, (2) more studies carried out on working farms, (3) more system approaches that include whole agro-ecosystems with farmers and other stakeholders, (4) value inquiries, (5) participative research and (6) reflective approaches. Papers published in Weed Research clearly demonstrate, that alternative research in the ideal is different from research in reality. The main difference between alternative and dominant research is in what gets studied, not in how it is studied. In conclusion, research in physical and cultural weed control may be evaluated successful in a dominant paradigmatic perspective but progress is very limited in an alternative paradigmatic perspective. There seems to exist a mismatch between ideals and reality in weed research, which challenges ideals as well as practice

Alternative versus conventional attitudes in higher agricultural education

From radical positions it is argued that it will take paradigmatic transformations to develop a sustainable agriculture and that values and attitudes have to be changed. To find out if teachers and students in higher agricultural education are motivated for radical changes a survey based on the Alternative-Conventional Agriculture Paradigm Scale (ACAP-scale) was conducted. The ACAP-scale shows how people relate to the alternative and conventional agricultural paradigm and it shows their overall understanding of how agriculture works and relates to the physical and social environment. This study showed that the ACAP-scale is a suitable method for quantitative assessment of attitudes to agriculture in a broader context. Among students and faculty members at the Royal Veterinary and Agricultural University, Denmark there exists significant differences in paradigmatic positions. Students’ course choices are, to some extent, influenced by their paradigmatic position, some courses enrol followers of either the alternative or the conventional agricultural paradigm, and females and older students hold more alternative views than males and younger students. It is concluded that the wide range of values and attitudes among students and teachers calls for new teaching methods, where values and attitudes are integrated. It cannot be taken for granted that teachers and students share the radical visions of sustainability as sometimes presupposed of bodies working for sustainable development

Digital images for assessing soil cover of crop plants

The main drawback by using crop soil cover in weed harrowing research is that it is assessed by visual scores, which are biased and context dependent. This problem may be solved by using digital image analysis. In this paper a new image capture standard and digital image analysis procedure was used to illustrate three key issues in relation to weed harrowing; selectivity, resistance and recovery. All issues require reliable assessments of crop soil cover. Crop soil cover was deduced from assessments of leaf cover, which is defined as the proportion of pixels in digital images determined to be green. Objective assessments of leaf cover and crop soil cover showed that the selectivity of weed harrowing in winter wheat and spring barley was unaffected by timing within a two weeks interval. Crop recovery, defined as the ability of the crop to recover from soil cover was determined in winter wheat and highly influenced by timing of weed harrowing. Increasing intensities of harrowing in growth stage (BBCH) 22 in winter wheat increased crop yields whereas crop yields declined by increasing intensities in growth stage 23 due to differences in the crop recovery capacity. Resistance defined as the capacity of the crop to resist soil cover was tested in barley, field pea and mixtures of barley and field pea. No differences were found between the crops. Future aims in mechanical weed control research are discussed in the context of the availability of unbiased crop soil cover data

TOLERANCE OF CEREALS TO POST- EMERGENCE WEED HARROWING

This study defines crop tolerance to post-emergence weed harrowing as the combined effect of crop resistance and crop recovery. Crop resistance is the ability of the crop to resist soil covering and recovery is the ability to recover in terms of yield. In two experiments, resistance, recovery and tolerance were quantified in barley, oat, wheat and triticale by a new method based on digital image analysis. Important differences in resistance, recovery and tolerance among species were seen and resistance was not linked to recovery. Oat showed higher resistance than wheat, and barley. Triticale showed the lowest resistance. Oat and barley showed both lower ability to recover from soil covering than wheat, and triticale showed complete recovery. Triticale was the most tolerant species followed by wheat, oat and barley. Differences in tolerance caused species dependent crop yield losses in weed-free environments in the range of 0 to 10% for a practical relevant aggressiveness of weed harrowing

Ukrudt - en del af helheden

Hvordan griber man ukrudt an i et økologisk landbrug? Og hvordan tænker man i det hele taget ukrudt ind i økologiens værdisæt

Hvad karakteriserer god undervisning?

Pædagogisk Udvalg udskrev tidligere på året en prisopgave med det formål at få kvalificerede forslag til, hvordan undervisningen kan se ud på fremtidens KVL. Mosaik bringer en forkortet version af 1. præmien

Ukrudtsharven kan afløse kemi

I 75 ud af 100 tilfælde kan en effektiv ukrudtsharvning i vårbyg erstatte kemi – uden at det går ud over økonomien. Men det kræver forskning og innovatio

Økologisk forskning er troværdig

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Assessment of leaf cover and crop soil cover in weed harrowing research using digital images

Objective assessment of crop soil cover, defined as the percentage of leaf cover that has been buried in soil due to weed harrowing, is crucial to further progress in post-emergence weed harrowing research. Up to now, crop soil cover has been assessed by visual scores, which are biased and context dependent. The aim of this study was to investigate whether digital image analysis is a feasible method to estimate crop soil cover in the early growth stages of cereals. Two main questions were examined: (1) how to capture suitable digital images under field conditions with a standard high-resolution digital camera and (2) how to analyse the images with an automated digital image analysis procedure. The importance of light conditions, camera angle, size of recorded area, growth stage and direction of harrowing were investigated in order to establish a standard for image capture and an automated image analysis procedure based on the excess green colour index was developed. The study shows that the automated digital image analysis procedure provided reliable estimations of leaf cover, defined as the as the proportion of pixels in digital images determined to be green, which were used to estimate crop soil cover. A standard for image capture is suggested and it is recommended to use digital image analysis to estimated crop soil cover in future research. The prospects of using digital image analysis in future weed harrowing research are discussed