Cereal Cover Crop Research Articles

Integration of Cereal Cover Crops in Ridge-tillage Corn (Zea mays) Production

Field experiments evaluating 11 cereal cover crops were established at two locations in Ontario over a two-year period. Cover crops were interseeded into a ridge-tillage corn crop and evaluated in terms of biomass production and winter annual, biennial, and perennial weed species suppression. Seedling establishment and aboveground biomass production of cover crops were variable between locations and years. At both locations over two years, ‘Danko’ winter rye, ‘OAC Halton’ winter barley and ‘Rodeo’ spring barley were the most consistent cover crops in biomass production. However, cover crop residues had no significant effect on weed biomass or density due to a high degree of spatial variability present in the weed populations. Corn grain yields were not reduced by the presence of inter-seeded cover crops when compared with the bare ground control treatment.

II. Cover crops and lucerne establishment

Abstract The effect of cereal cover crops on the establishment of lucerne was studied in three field trials at Lincoln. A barley cover crop sown with lucerne in the spring had no effect on lucerne establishment, at barley seeding rates of 56 and 112 kg/ha and lucerne seeding rates of 2.2 to 36.0 kg/ha. In one trial a winter sown wheat cover crop had no effect on the establishment of lucerne sown into it in the spring, but in another trial establishment was reduced, the reduction being less, however, than when lucerne was sown with the wheat in winter. Irrigation improved lucerne establishment and reduced competition from the cover crop. Establishment of lucerne sown in March was less successful after a cereal crop than after fallow, but sowing in September after fallow was preferable.

Surveys of sugar-beet seed crops, mangold clamps and weedsin England for aphids and viruses, 1963–73

SUMMARYThe annual patterns of infestation of sugar-beet root and seed crops by green aphids (Myzus persicae) and by black aphids (Aphis fabae) were similar, paralleling population changes shown by catches on sticky traps in southern England, but the incidence of yellows in root crops was not correlated with incidence in seed crops in the same year. Few green aphids overwintered on beet-seed plants and the incidence of yellows was consistently low in the main seed-growing areas where all the stecklings are raised under cereal cover crops. Elsewhere, yellows sometimes spread in the autumn and many green aphids occasionally overwintered. Black aphids were seldom prevalent; the severity of attack correlated with the number of eggs laid on spindle (Euonymus europaeus) during the previous autumn.Twenty-two per cent of mangold clamps checked in mid-April contained aphids, but only about 5 % contained M. persicae. Seventeen per cent of the infested clamps contained aphids infective with BMYV and 10% contained aphids infective with BYV. However, the acreage of mangolds grown in England has decreased.Myzus ascalonicus overwintered on weeds more often than M. persicae or other species likely to act as vectors of viruses affecting sugar beet. Forty per cent of samples of some common weeds collected from sheltered sites during mid-April from 1963 to 1973 were infested with aphids, and those on chickweed (Stellaria media), groundsel (Senecio vulgaris) and shepherd's purse (Capsella bursa-pastoris) were commonly infective with yellowing viruses. Weeds are probably a major source of yellowing viruses in southern England.

Some observations on the economic importance of sugar‐beet downy mildew in England

SUMMARYSugar‐beet downy mildew is most prevalent in England in the sugar‐beet and mangold seed‐growing area of South Lincolnshire and West Norfolk. The most widespread and severe recent outbreaks were in 1957, and in 1965 when 6412 acres were reported with more than 10% infected plants. The fungus usually overwinters in sugar‐beet and mangold seed crops, and in England other ways of overwintering are seldom important. Steckling beds are infected in the autumn, and the disease may increase rapidly in the seed crop in early spring. Summer‐sown stecklings get more downy mildew than stecklings sown in spring under a cereal cover crop, and direct‐drilled seed crops get more downy mildew than transplanted crops.

Establishment studies II. The effect of method of establishment on a 1 year ley in the seeding year

The influence of undersowing on the establishment of broad red clover and Italian rye-grass was investigated under three managements and two levels of nitrogen applied in spring. The following conclusions are drawn:1. The cereal cover crop reduced the aggressiveness of Italian rye-grass towards red clover.2. The cereal cover crop produced a high initial yield of dry matter and crude protein. In midseason, when keep from maiden seeds is important, the highest yield was obtained in the absence of the cereal cover crop.3. The danger of failure in the take of undersown herbage seeds is increased when soil moisture is very low.4. Total dry-matter yield in the seeding year was increased by using a cover crop, but starch-equivalent yield was not greatly affected. Crude-protein production was increased when the cover crop was cut for silage or frequently grazed, but not when a grain crop was harvested.5. Undersowing Italian rye-grass and clover gave a higher yield of dry matter, starch equivalent and crude protein than sowing the herbage after the cereal was harvested.6. The cover crop depressed weed growth, and ‘Nitro-Chalk’ increased it, except where Italian rye-grass was undersown.7. The application of ‘Nitro-Chalk’ increased the yield of dry matter, particularly early in the seeding year. ‘Nitro-Chalk’ encouraged the growth of Italian rye-grass and oats but depressed the clover. This reduction in legume yield was least when defoliation was frequent. The influence of nitrogen on plant growth was especially noticeable when soil moisture was low and a cover crop used.

THE EFFECTS OF SEED RATE, CLOVER AND APPLIED NITROGEN ON BROADCAST SEED CROPS OF PASTURE RYEGRASS

This investigation was carried out with leafy varieties of perennial ryegrass at four centres near Aberystwyth over a period of three years. Nitrogen applied in spring increased lodging, the number of fertile tillers and also seed yield, except where sowing was made without a cereal cover crop. While reasonable yields were obtained from badly laid crops, it is suggested that lodging prior to anthesis has an adverse effect on seed yield. Clover included as a companion species tended to depress the yield of seed and increase the degree of lodging.Seed rate had less infiuence on lodging and seed yield, but the data show that similar yields were obtained from light seed rates of 4 lb. per acre as from the heavier rates. On the other hand, there was a tendency for the low rate of seeding to produce weedy plots, especially when sown in the absence of a cover crop.