Yield Losses In Barley Research Articles

The Effects of Organomercury Seed Treatment on Barley Artificially Inoculated with Fusarium spp.1

Artificial field inoculation showed that in one year out of two, Fusarium roseum caused significant yield loss in barley grown from organomercury‐treated seed. No significant yield loss occurred in either year as a result of inoculation with Fusarium nivale. Results from field, pot and blotter tests suggested that inoculation with F. nivale and sometimes F. roseum could at times be associated with increased vigour in barley. There was a fairly consistent trend particularly with F. nivale for this to occur to a greater extent in plants from untreated seed than in those from treated seed. Similarly, any reductions in vigour associated with inoculation with more pathogenic strains of either species occurred only, or to a greater extent, in plants from treated seed. There was some evidence of an increased capacity for regenerative root and shoot growth in barley plants damaged by Fusarium inoculation, and it is suggested that increased growth may be associated with increases in percentage dry weights of the shoot 8 but not 18 days after inoculation. In the absence of inoculation, the effect of seed treatment was to increase grain yields, though this was not clearly associated with the increases it sometimes caused in emergence and in 1000‐grain weight.

Yield loss in barley associated with Sinapis arvensis L. (charlock) after continuous routine use of herbicide

Summary: Résumé: ZusammenfassungUncontrolled S. arvensis (charlock) in barley, after many years successful control with herbicides, was associated with yield losses of 48‐71%, mostly due to smaller ear populations. Curtailing herbicide use by spraying in alternate years only might not be a suitable strategy for reduction in herbicide usage where charlock is a dominant weed. Pertes de rendement dans les cultures d'orge, provoqueés par Sinapis arvensis L. aprés l'utilisation routinière et continue d'herbicides La non destruction de Sinapis arvensis dans l'orge, après de nombreuses années de lutte efficace avec des herbicides, a provoqué des pertes de rendement de 48 à 71%, dues principalement à des populations plus faibles d'épis. La réduction de I'utilisation d'herbicide, par des traitements alternés d'une année à l'autre, ne semble pas constituer une stratégie adéquate pour diminuer l'emploi des herbicides, là où la moutarde est une mauvaise herbe dominante. Ertragsverluste in Gerste durch Sinapis arvensis L.(Acker‐Sent) nach ständigem Routineeinsatz von Herbiziden Wurde S. arvensis in Gerste, nachdem es über viele Jahre erfolgreich mit Herbiziden bekämpft worden war, nicht bekämpft, dann war das mit Ertragsverlusten von 48–71% verbunden. Der Ertragsrückgang war hauptsächlich auf eine geringere Ährenrahl zurückzuführen. Eine Beschränkung des Herbizideinsatzes in Form von Spritzungen nur in jedem zweiten Jahr, durfte deshalb auf Standorten, wo der Acker‐Senf als dominierendes Unkraut vorkommt, keine òrauchbare Alternative zur Einsparung von Spritzungen sein.

Relationship Between Cereal Root-Knot Nematode Meloidogyne Naasi and Growth and Grain Yield of Spring Barley

Yield of spring barley was reduced by increasing nematode population density in a field trial with cv. Sabarlis on Meloidigyne naasi infested land. A series of significant linear regression coefficients relating nematode population density, host symptoms and barley growth and yield was obtained. Grain yield was reduced by 3.5% for every 10 juveniles/g soil reaching 50% loss at 150 juveniles/g soil. Fertile ear production was the major but not sole yield component affected. The field trial indicated an equilibrium density of approximately 40 juveniles/g soil for the nematode. A glasshouse experimental confirmed the field trial results. Yield loss in barley could be expected at small preplant densities with economically significant loss at initial densities greater than 20 juveniles/g soil. In pots, aldicarb at 5.6 kg a.i./ha prevented yield loss at 98 juveniles/g soil whereas yield was not increased by aldicarb on uninoculated pots. Treatment of field plots with aldicarb resulted neither in heavier yields nor smaller final population densities possibly due to poor incorporation and a dry season. At present lack of survey data precludes an assessment of the economic importance of M. naasi in Britain. However, in Wales changed cropping patterns have resulted in increased field populations of this nematode.

Yield losses in barley, wheat and potatoes associated with field populations of'large form‘ Longidorus leptocephalus

SUMMARYThree field experiments made during 1975‐77, in North and South Yorkshire, investigated the influence of ‘large form’Longidorus leptocephalus upon the yield of spring barley, winter wheat and second early potatoes. Longidorus populations ranged from undetectable levels to 2375/litre soil. At one site estimates of nematode numbers were made twice, and gave a close agreement between the ranking order of plots. Significant negative correlations between numbers of L. leptocephalus and yield suggested that this nematode impaired the yield of these crops. For each 200 LongidoruslX of soil the estimated reductions in yield were 0–25 t/ha of barley, 0–13 t/ha of wheat and 0–55 t/ha of potatoes.

COMPARISON OF THE EFFECTS OF NET BLOTCH AND LEAF REMOVAL ON YIELD IN BARLEY

Experiments were conducted in a growth cabinet to compare yield losses in barley caused by partial defoliation and foliar infection by Drechslera teres, the causal agent of net blotch. When Gateway barley was grown under a low fertilizer regime, infection of lower leaves caused greater yield reductions than the removal of comparable leaves. In contrast, infection or removal of upper leaves reduced yields to about the same extent. Under a higher fertilizer regime, yield reductions from infection or defoliation were about equal (14%). These losses were considerably lower than those from plants on the low fertility regime and were similar to those caused by net blotch in the field.In leaf clipping experiments, root weights and yields were reduced proportionately to the amount of leaf tissue removed. The time required to head was also increased with increasing amounts of leaf clipping.