Herbage Mixtures Research Articles

EFFECTS OF SEEDING RATE OF ORCHARDGRASS ON THE BALANCE OF SPECIES IN A HERBAGE MIXTURE

A seed mixture of Dactylis glomerata, Bromus inermis, Festuca rubra, and Trifolium repens was sown in each of 3 years. Amounts of D. glomerata were varied from 0 to 7.7 kg/ha in 1.1-kg increments. Amounts of the other species were adjusted in a constant proportion to keep the total seeding rate at 22.4 kg/ha. Plots were harvested three or four times a year for 5 years after the initial sowing. By the second year after sowing D. glomerata comprised 50–75% of the herbage mixtures at all seeding rates. T. repens comprised 30–40% of the herbage mixture where D. glomerata was excluded, and as little as 7% where D. glomerata was included. The means for all years showed the highest yield of herbage from the mixtures containing little or no D. glomerata, due mostly to their higher content of T. repens. The conclusion was that the rate of D. glomerata would have to be less than 1 kg/ha to maintain B. inermis and F. rubra in the mixture.

SHEEP PRODUCTION ON IRRIGATED PASTURE AS INFLUENCED BY FORAGE MIXTURE AND FERTILIZATION

Yearling white-faced ewes were used to compare the production from four herbage mixtures with two levels of fertilization for 6 consecutive years. There was a significant difference in kilograms of gain, sheep-grazing days, total digestible nutrients (T.D.N.) production, and average daily gain due to pasture mixtures and fertilizer treatments. There was also a difference in production associated with years.The average annual gain, grazing days, and T.D.N. production per hectare were 433 kg, 3689 days, and 3318 kg, respectively. The average daily gain was 0.12 kg for all mixtures, years, and fertilizer treatments combined.The herbage mixture of orchardgrass, smooth bromegrass, creeping red fescue, and ladino clover gave the most satisfactory yields when all criteria were considered. The same mixture without clover produced the lowest yields. The addition of clover raised the production more than did the moderate applications of fertilizer. A mixture of orchardgrass, tall fescue, reed canarygrass, and alfalfa was very productive for 3 years. However, as the amount of alfalfa decreased the gain per hectare and the daily gains of the sheep also decreased, but carrying capacity increased.

INTERACTIONS IN FORAGE YIELD TRIALS

A study was conducted to evaluate the effects on forage yield of interactions between a few common management treatments and herbage mixtures. Relative yields of the species and mixtures under comparison varied with the amount of fertilizer applied, stage of growth prior to harvest, stubble height, and seeding method. The response of grass to nitrogen fertilization varied with the height of stubble left after harvest. It was concluded that interactions may occur in the simplest of forage yield tests because of the treatments used. Possible methods of avoiding interactions are discussed.

Establishment studies V. The effect of method of establishment on the behaviour of long-term leys in the seeding year

1. In the seeding year the total dry-matter yield in swards sown without a cover crop was increased by infrequent defoliation, but the yield of crude protein was decreased. The highest production of starch equivalent was obtained when a cover crop was used.2. In the absence of a cover crop, the yield of red clover was higher under infrequent defoliation, but the yield of white clover was higher under frequent grazing.3. Frequent grazing, and the use of a cover crop, reduced the ingress of weeds more than infrequent defoliation. Nitrogen applied to the cover crop also reduced the growth of weeds.4. Nitro-chalk increased the total yield of herbage except when under a cover crop; it reduced the growth of red and white clovers, but this was not so marked under frequent grazing.5. Nitro-chalk increased the annual yield of crude protein under frequent grazing, but decreased it in all herbage mixtures under infrequent defoliation; nitrogen had no effect when a cover crop was used. The increase in yield of starch equivalent due to the application of nitrogen and its apparent recovery was greater under frequent grazing than under the other two managements. Under infrequent defoliation, in the absence of a cover crop, the recovery of nitrogen was particularly low.6. The ryegrass mixture and ryegrass-dominant general-purpose mixture made more growth, and suppressed clover and weeds to a greater extent than did the timothy and cocksfoot mixtures. This was modified by management in that ryegrass was particularly aggressive under frequent grazing (management 1) but not under managements 2 and 3.7. In the autumn of the seeding year the yield of total herbage was highest under infrequent defoliation, particularly in the cocksfoot, and general-purpose swards. All undersown mixtures gave lower yields than when no cover crop was used.8. Nitrogen increased the yield of herbage in May and June under frequent grazing, and in the August cut under infrequent defoliation, but in the autumn particularly it was reduced where a cover crop was used.9. The application of nitrogen decreased the protein content in all herbage mixtures when a cover crop was used or when defoliation was infrequent. Under frequent grazing the nitrogen increased the percentage of crude protein in the first two grazings, but decreased it in the September grazing.10. The production from the various mixtures was modified by management: under frequent grazing in May the ryegrass-dominant mixtures were higher yielding than the others, but in July the general-purpose and cocksfoot swards were the most productive. Under infrequent defoliation in August the timothy mixture had the highest yield and cocksfoot the lowest, and under this management cocksfoot and timothy swards had the highest yield in the autumn of the seeding year.

Establishment studies. IV. The effect on spring oats of undersowing with long-term ley mixtures

The effect of undersowing on a spring oat crop with four long-term ley mixtures was investigated. Ryegrass, cocksfoot, timothy and general-purpose mixtures were used; broad red and white clovers were included in all mixtures and two levels of nitrogen applied, no nitrogen (n0) and Nitro-Chalk at 3 cwt./acre.1. Panicle number was reduced by all the undersown mixtures except when cocksfoot was the only grass sown (mixture B).2. The weight of individual grains was slightly reduced by undersowing with a ryegrass-dominant general-purpose mixture (D) in the absence of Nitro-Chalk, and there was also an indication of a lowering of the total number of grains per panicle when Nitro-Chalk was applied.3. All the herbage mixtures reduced the percentage of kernel at both nitrogen levels under the ryegrass-dominant mixture (A), but only at one level of nitrogen when cocksfoot (mixture B) or timothy (mixture C) were the only grasses sown.

EFFECTS OF CLIPPING AND NITROGEN ON COMPETITION BETWEEN THREE PASTURE SPECIES

In three herbage mixtures comprised of different combinations of orchardgrass, Dactylis glomerata L., creeping red fescue, Festuca rubra L., and common white clover, Trifolium repens L., highest yields of the grasses were obtained when 1) harvesting was delayed until only 2 per cent of the incident light near mid-day penetrated to the base of the sward rather than at 10 per cent penetration, 2) a 2-inch rather than a 4-inch stubble was left after cutting, and 3) nitrogen fertilizer was applied. The same cutting treatments gave maximum yields of the associated clover without nitrogen fertilization, but when nitrogen was applied higher clover yields were obtained when cutting was at 10 per cent light penetration. Yields of the two grasses were approximately the same when grown with clover only, but in the two-grass association orchardgrass held the fescue to a low proportion in the mixture.Results did not support the concept of maintaining a specified minimum leaf area index (LAI) for maximum yield of the herbage mixture.