Optimization of Inter-Row Spacing and Nitrogen Rate for the application of Vision Guided Inter-Row Weeding in Organic Spring Cereals

Flex-tine weed harrowing conducted as a full-width operation treating both crop and weeds is the principal method for direct weed control in organic spring cereals in Northern Europe. Results with this technology have varied considerably where especially crop injuries and control failures against tall-growing and tap-rooted weed species have been major drawbacks. New camera technology capable of detecting crop rows makes it possible to employ selective weed control in spring cereals. Normally cereals are grown at 12.5 cm row spacing in Northern Europe but even a moderate extension of the row spacing can make enough room for implementing automatically steered inter-row hoeing. Experiences from practice have shown that camera-based steering systems can guide a hoe blade accurately in a 20-25 cm wide inter-row space. The steering systems have also improved work rates by increasing implement width and forward speeds and the technology is gradually being employed on an increasing number of organic farms. Growers claim that crop injuries are negligible and weeding effectiveness against problematic weed species has improved compared with weed harrowing. However, the cereal cropping system has not been optimized to the usage of inter-row cultivation. Intra-row weeds, i.e. those growing in the crop lines, are not controlled and increasing the row spacing to 25 cm or more may cause a yield penalty. The aim of this study was to investigate the interaction between inter-row cultivation, inter-row spacing and nitrogen rate on weed and crop growth. Results are reported from two years field experiments with spring barley and spring wheat. It was aimed to maintain a constant seed rate for all five row spacing studied (12.5, 15, 20, 25 and 30 cm), which gave a higher crop density in the rows with increasing row spacing. A denser intra-row crop stand would improve the suppression of surviving intra-row weeds and partly compensate for the more weed growth that wider row spacing would cause by allowing more light penetration into the crop canopy. It was found that maintaining the seed rate when increasing row spacing was important for preserving crop yields. The best results in terms of weeding effectiveness and crop yield were achieved with 15 and 20 cm row spacing and high N rate; most evident in spring barley. It was seen that the traditional ‘Ducksfoot’ blade is not an optimal solution for inter-row cultivation at small row spacing. As a consequence, a new blade has been developed which is also presented at the WSSA 2016 Annual Meeting

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Article explaining the use of inter-row cultivation for weed control in cereal

Inter-row hoeing for weed control in organic spring cereals

New camera technology capable of detecting crop rows now makes it possible to employ selective weed control in spring cereals. Cereals are normally grown at 125 mm inter-row spacing but even moderate extension of the spacing can make enough room for automatically steered inter-row hoeing; the technology is being employed on an increasing number of organic farms. However, intra-row weeds, i.e. those growing in the crop lines, are not controlled and increasing the inter-row spacing to ≥ 250 mm may cause a yield penalty. The aim of this study was to investigate the interaction between inter-row cultivation, inter-row spacing and nitrogen rate on weed and crop growth. Results encompass four years field experimentation with spring barley and spring wheat including studies on optimal hoe blade configurations for hoeing at narrow inter-row spacing. Weeding effectiveness was generally greater in barley than in wheat but with minor differences between the inter-row spacing studied (125-150-200-250-300 mm). Maintaining the seed rate when increasing inter-row spacing was important for preserving crop yields and in most cases wide inter-row spacing (300 mm) did not yield less than the other spacing. Nitrogen rate only affected crop yields. The traditional ‘Ducksfoot’ blade was not optimal for inter-row hoeing at small row spacing due to excessive side wards soil movement covering the crop leaves. Two new hoe blade designs performed better in this regard and especially the one design was very stable during operation. Inter-row hoeing for spring cereals is particular promising for weed control at high weed infestation levels, and where many erect and tap-rooted weed species are present

Inter-row hoeing for weed control in organic spring cereals-Influence of inter-row spacing and nitrogen rate

Olesen, Jorgen E/0000-0002-6639-1273; Jabran, Khawar/0000-0001-8512-3330; De Notaris, Chiara/0000-0002-3764-012X; Melander, Bo/0000-0002-5183-3278WOS: 000452942600006Inter-row hoeing has become increasingly important for weed control in organic spring cereals since the introduction of automatic steering systems. The technology requires a widening of current inter-row spacing for spring cereals in order to provide sufficient room for accurate operation of a hoe share between crop rows. However, there is considerable uncertainty about the optimal combination of inter-row hoeing, inter-row spacing and nitrogen (N) rate in terms of weeding effectiveness and crop yield. The aim of this study was to investigate the effect on weed and crop growth of the interaction between five inter-row spacings (125, 150, 200, 250, and 300 mm) and two N rates (50 and 100 kg NH4-N ha(-1)). Three field experiments were conducted in spring barley and two in spring wheat. One hoeing pass was applied for each inter-row spacing using a share width that worked 15-47 mm from the crop row. The immediate effect on weed numbers following hoeing was a 80-90% reduction in barley and a 63-80% reduction in wheat, but with no significant differences between spacings and N rates. However, the effect on weed biomass at crop anthesis was minor in barley because the crop itself substantially suppressed weed growth. Spring wheat was less competitive and inter-row hoeing reduced weed biomass by 60-70% compared to the standard 125 mm spacing without hoeing. The widening of inter-row spacing appeared not to reduce crop yield or grain quality. Prerequisites for successful inter-row hoeing in spring cereals include retained crop stands when increasing inter-row spacing and the avoidance of crop injuries from inaccurate steering.Ministry of Environment and Food of Denmark; International Centre for Research in Organic Food SystemsWe acknowledge the Ministry of Environment and Food of Denmark and the International Centre for Research in Organic Food Systems for funding this research, which was part of the RowCrop project under the Organic RDD2 programme. We would like to thank technicians Eugene Driessen and Karen Bjorn Heinager for their skilful technical assistance and Agrolntelli (www.agrointelli.com) for delivering the equipment for sowing and inter-row hoeing

Metabolic characteristics of prehypertension: role of classification criteria and gender

Objective: We tested whether men and women in the European Society of Hypertension (ESH) high normal and normal blood pressure (BP) categories, all included in the the Seventh Joint National Committee (JNC 7) prehypertension group, share similar metabolic characteristics and whether they differ from men and women with optimal BP (greater than 120/80 mmHg). Methods: BP (multiple measurements with a standardized automatic device), insulin sensitivity (euglycaemic clamp), oral glucose tolerance test (OGTT), carotid intima-media-thickness (IMT, echo), family history (questionnaire), physical activity (accelerometer), and anthropometrics (bioimpedance) were evaluated in the 1384 healthy European individuals ranging from 30-60 years participating in the multicentre study Relationship between Insulin Sensitivity and Cardiovascular disease (RISC). Results: BMI and waist-to-hip ratio were higher (both P greater than 0.05 adjusted for age and recruiting centre) in men and women with high normal (but not normal) BP with respect to optimal BP. Similarly, in women (after adjustment for study centre, age, physical activity, and waist), serum triglycerides and carotid IMT were higher in those with high normal (but not normal) BP; moreover, in this group there was a higher prevalence of glucose-intolerance (21.8 versus 9.7%, P=0.02) and insulin sensitivity tended to be lower (P=0.07). Insulin sensitivity and diastolic blood pressure were weakly related variables displaying a nonlinear association with a threshold below the normal BP values and no interaction with family history of hypertension. Conclusion: The JNC 7 category prehypertension identifies a dishomogeneous group of individuals whereas the ESH classification, particularly in women, was more accurate in identifying both the predisease and the healthy phenotype. Insulin resistance is not a major characteristic of the condition of prehypertension

A new hoe share design for weed control: measurements of soil movement and draught forces during operation

This research introduces a new share design (L-share) that reduces the undesired random soil movement, providing a more controlled disturbance of the upper soil layer. Purpose: The aim of this study was to evaluate draught forces and soil movements when operating the new share. Materials and Methods: Experiments were conducted in a laboratory set-up using a soil bin with a fine loamy soil texture. The soil was compacted to a bulk density of 1500 kg m−3, with a penetration index of 486 kPa and a mean water content of 10%. The cultivation depths were 30, 50 and 70 mm and the operation speeds were 0.84, 1.67 and 2.31 m s−1. Cubes were used to measure soil movement by recording the displacement from their initial positions. The soil surface and furrow profile were measured by using a 2D laser range scanner. Results: The results showed that increasing operation speed and cultivation depths generally increased draught forces and soil movement. Changing the cultivation depth from 30 to 50 mm resulted in a 63% greater longitudinal force (Fx), and 71% greater Fx when increasing the cultivation depth from 50 to 70 mm. Conclusion: The study showed that the new L-share mounted on a modified spring tine only causes minor soil movement and thereby minimising the undesirable soil movement