Recent results in the development of band steaming for intra-row weed control

The recent achievements with developing band-steaming techniques for intra-row weed control in vegetables are presente

Aspects of steaming the soil to reduce weed seedling emergence

Aspects of using steam for intra-row weed control in organic row crops are presented

Prospects and limitations for agricultural engineering in the development of sustainable weed control methods – examples from European research

This paper gives a brief review of the major achievements in European research on physical weed control methods for agricultural and horticultural crops. Most of the work has emerged from an increasing awareness and concern about pesticide consumption in many Western European countries. Also an increasing interest in organic farming has further pushed the development of more sustainable weed control methods. Generally, the research has been joint projects between engineers and agronomists and the results have so far revealed some prospects as well as limitations for non-chemical methods to become useful solutions, not only for the organic growers but also for the conventional ones. A number of investigations have focussed on rather simple low-tech mechanical weeding principles, such as harrowing, brush weeding, hoeing, torsion weeding, and finger weeding, aiming at describing the weeding mechanisms for a better optimisation of the usage. In some crops, such as transplanted vegetables, potatoes, maize, winter oil seed rape, and partly small grain cereals, mechanical weed control has been quite effective and may become a relevant alternative to chemical weed control. However, current mechanical methods generally work with low selectivity, as they do not distinguish between weed and crop plants when applied into the crop row. Attempts to change the constructions and materials of the weeding tools have not decisively improved the selectivity and more intelligent methods capable of controlling only the weeds are therefore needed. The first step in that direction was the introduction of electronic steering systems for automatic guidance of inter-row hoes. They are based on image analysis of the crop row, and the technology is considered to be a kind of platform for the development of more advanced systems for robotic weeding in the rows of row crops, such as sugar beets, maize, and most vegetables. However, recent studies have shown that such an ambition may be difficult to fulfil because weed plants growing right beside the crop plants are the most harmful ones in terms of suppressing the crop plants. Whether any computer-based system would be able to guide a cutting device with sufficient accuracy and speed to remove those weeds in a practical situation in row crops seems questionable. Hence, other projects have been started with a view to avoid this challenge, trying to look for less complicated methods with more short-termed prospects of being applicable in practice. Steaming the soil prior to crop establishment and in bands corresponding to crop rows appears to have some potential in that context since an almost complete intra-row weed control can be achieved without affecting the crop. However, as with most other thermal methods, high energy consumption is a key-issue that needs to be solved

Combining physical and cultural weed control with biological methods – prospects for integrated non-chemical weed management strategies

The paper deals with the possibilities of combining physical weed control with biological weed control

USE OF A RAT MODEL TO ELUDICATE IMPACT OF ORGANIC FOOD ON HEALTH

Ingredients (potatoes, carrots, peas, green kale, apples, and rapeseed oil) were grown according to three different cultivation systems (“Organic”, low input of fertilizer without pesticides; “Minimally fertil-ised”, low input of fertilizer and high input of pesti-cides, “Conventional”, high input of fertilizer and high input of pesticides). Three iso-energetic and iso-nitrogeneous diets were composed of equal propor-tions of the ingredients originating from each of the cultivation systems, and the diets were investigated with respect to several physiological responses and biomarkers of health using a rat model. In addition, the diets were tested in a food preference test using the same type of rats, but another generation. In both experiments, the diets were optimized according to the nutritional requirements of reproducing rats, except for a high content of fat. Most of the measured variables (biomarkers of health) showed no differ-ences between the experimental diets, however, some differences between dietary treatments were obtained, which were in favour of the “organic” diet contrasted with the “conventional” diet. The prefer-ence test showed a significant interaction between diet choice and mother’s diet. However, the results obtained from the present study cannot be extrapo-lated to all organic and conventional cropping sys-tems, mainly because crops were grown only in one replication. Thus, it is of outmost importance that future investigations on the effect of organic food in relation to human health and well-being should be based on well-defined and controlled food produce system with replication

Band steaming for intra-row weed control in direct-sown vegetables

Recent results with band-steaming in organic vegetables are presented

Effects of culivation conditions for apples on growth rates of fruit fly larvae and contents of phenolics

The different cultivation treatments significantly and systematically affected both rate of development of fruit fly larvae and contents of phenolic compounds, but not the total number of flies produced. This is in accordance with the hypothesis that cultivation methods can give large enough changes in composition of plant foods to affect physiological aspects important for health of consumers. It indicates that further stusies should be made of the links between plant cultivation, plant composition and health, for example regarding the question of the nutritional value of organic versus conventional food

Sensory quality of scab-resistant apple cultivars

Twenty-two scab-resistant apple cultivars were harvested in autumn 1999 and evaluated for sensory quality the following October, November and December. Multivariate analysis was effective in describing the comblex relationships and variabillity among the numerous attributes used to characterise apple quality. Crispness, mealiness, skin toughness, apple flavour, sweetness, unripe flavour and overripe flavour were informative attributes describing the variation in the sensory quality. Texture attributes, apple flavour and overripe flavour were affected by storage. Extended storage resulted in an increase in mealiness and overripe flavour and a decrease in crispness, juiciness and apple flavour. Many potential scab-resistant cultivars were suitable for consumption in October: 'Dayton', 'Primicia', 'Retina' and 'Realka'; in November: 'Merlijn', 'Saturn', 'Initial', 'Realka', 'Rajka' and 'Rubinola'; and in December: 'Otava', 'Ecolette', 'Rejka', 'Rubinola', 'Delorina', 'Initial' and 'Resista' and 'Topaz'. This study gives a sensory sharacterisation of scab-resistant cultivars as an indicator of suitability for commercial growing and marketing of low-input apple cultivars

INTERGRATING PHYSICAL AND CULTURAL METHODS OF WEED CONTROL – EXAMPLES FROM EUROPEAN RESEARCH

The most recent advances in European research on non-chemical weed control methods and strategies for horticultural and agricultural crops are presented

Do nutrient uptakes and grain yields differ between spring barley varieties grown for organic farming as mono-crop and in mixture: Characteristics of spring barley varieties for organic farming

Manure application increased yield. Hence the study was conducted under the conditions of moderate nutrient stress and in all probability nitrogen stress. Under this condition nutrient uptakes, biomass production and grain yields did vary between Otira, Orthega, Landora, Brazil, Svani, NK96-300, Mixture 1 (Otira, Orthega, Landora) and Mixture 2 (Brazil, Svani and NK96-300). Interaction between variety and soil fertility treatments were also significant. These findings open new possibilities for selection or plant breeding for genotypes with improved capability of nutrient acquisition from soils at different soil fertility levels e.g. in organic farming. Cropping of barley varieties in mixtures seems to increase (stimulate) nutrient uptakes (N, P, S, K, Mg, Ca, Mn, Zn, Cu and Mo) and biomass production