STRAIN INVESTIGATION OF GRASSES AND CLOVERS.

New Zealand Journal of Agriculture, Volume 47, Issue 6, 20 December 1933, Page 366

STRAIN INVESTIGATION OF GRASSES AND CLOVERS.

( Continued.)

ITALIAN, WESTERN WOLTHS, AND WIMMERA RYE-GRASSES.

E. Bruce Levy,

Agrostologist, and Stephen H. Saxby, Assistant in

Agrostology, Plant Research Station, Palmerston North.

Italian rye-grass, Western Wolths rye-grass, and Wimmera rye-grass are all short-lived species. Italian lasts well for twelve months, Western Wolths for round about six months, and Wimmera about three months. Each species has a more or less specific niche in arable and grassland farming.

The annual crops of the world from a food and clothing point of view are of paramount importance. The annual enables profitable land exploitation over a much wider front than is the case with the perennial. In grassland farming the annual species greatly extend the range of soil types that can be successfully farmed per medium of the grazing animal.

The reason why the annual is successful where the perennial fails, in so far as bulk is concerned, lies in the simple fact that soil aeration and moisture absorption and conservation are improved through the cultivation and soil mulching that precede the sowing of the annual. Artificial manures applied at seeding-down time are incorporated deeper in the soils in . contact with soil moisture, and this makes manuring on the drier soil effective and profitable, whereas those manures applied to. the dry surface in permanent , grassland may be unavailable to the plant. Successful, exploitation of the high-producing annual grassland species such as Italian, Western Wolths, and Wimmera rye-grasses therefore demands the annual breaking-up and cultivation of the land prior to seeding. Without this annual breaking-up and cultivation—unless one happens to be farming on soils that are self-mulching during periods of drought, or on extremely fertile soils, that. are sufficiently fertile to establish the annual from shed seed without the assistance afforded by breaking up . and cultivationthe high-producing annuals are . of little or no value to the grassland farmer. Perennial species on dry soil or on low-fertility soils are universally . low-producing. Their production increases as the available soil fertility increases, - until a point is reached where the high-producing perennial species will yield equally, or almost so, to the high-producing annual species, and there is a point in grassland farming where the extra production from the annual species over and above that possible from, perennial species on the same soil-type does not pay for the added cost of cultivation,, seeding, and loss of feed while the ground is under cultivation. This economic factor really delineates arable farming, short-rotation farming, and permanent grass farming the one from the other.

In short-rotation farming the grassland area on the farm usually rapidly deteriorates in carrying capacity in the second, third, and .subsequent years, until it again is broken up in the course of the rotation. The choice of species and strains of these for the shortnotation pasture may, however, greatly influence the production of

the short-rotation pasture in its second and subsequent years, and the writers feel that on many soil-types the grass period in the rotation may be profitably extended by the use of the certified type of perennials.

Certification during the. last four years has brought prominently before the grassland farmer the perennial . strains of pasture plants,, and more particularly perennial rye-grass. In the South Island, prior to certification, the type of perennial rye-grass used was dominantly of an annual- nature, and the fact that this type had developed in the South Island, where arable farming is most pronounced, is in itself significant as indicating the very great value of the annual type to. South Island conditions in general. In the South', however, the development of the annual type had gone too far (even for the South) in so far that the grassland farmer who really .could do with perennial specieswas unable to rely on the commercial article sold as perennial rye-grass.. What the certification system has done is simply to enable the farmer who wants a truly perennial species to buy with confidence on theassurance that he will get what he requires.. p Certification in many farmers’ minds has also incidentally created the impression that the true perennial is preferable to the annual for all soil types and conditions. Certification has no such aim, and, asresults of the present strain investigations will indicate, there is just as great a need for certified good annual types as there is for certified good perennial types ; both have their distinct place and sphere of usefulness in grassland farming.

Palatability of Annual Rye-grass compared with Perennial. ; The annual rye-grasses while they last are distinctly more palatable than. the perennial rye-grasses, given the same soil conditions and identical stage of growth when stocked. False perennial, rye-grasses vary in palatability according to the degree of hybridism and according to which parent they resemble. False perennials throwing dominantly to the Italian parent are equal in palatability to Italian itself, while hybrids throwing more to the perennial parent are less and less palatable according to how closely they resemble the perennial parent. Palatability, however, in any one species is relative to stage of growth when eaten. Young, freshly growing herbage in perennial rye-grass, is palatable, while poorly grown, stunted, matured herbage is unpalatable. Thus between Italian rye-grass (and its hybrid derivatives) and poorly grown, stunted, matured herbage of the true perennial, • there is a wide range in degree of palatability. The normal crops of Italian rye-grass are consumed during the year subsequent to sowing down, and the growth, as a result of cultivation and manures applied, is usually fresh and growing vigorously. Hence the palatability is excellent. In the case of the perennial rye-grass, this is still grazed long after the effects of cultivation have disappeared in years subsequent to establishment, and unless the climatic conditions are such or topdressing has been such as to maintain a high surface-soil fertility, the growth of the perennial may become yellow, stunted, and mature, with little or no fresh leaf forming. Thus, in comparison with Italian ryegrass, true perennial becomes distinctly unpalatable.

Little or no management is required in the annual rye-grass to keep it palatable. Specialist management is imperative for keeping a

perennial rye-grass perennially palatable. The addition of Italian rye-grass to a mixture of perennial rye-grass and clovers will undoubtedly increase the palatability. For the grazier, therefore, where high palatability is required combined with a pasture of three to four years’ duration, a mixture of Italian rye-grass and perennial rye-grass plus clovers should give in the first year at least (or for the normal life of the annual included in the mixture) a pasture almost equal in palatability to a pure sowing of Italian rye-grass, Western Wolths, Wimmera rye-grass, or a bad false perennial; and in the second and subsequent years the farmer must be content with slightly less palatable pastures, the true perennial element of the sward alone surviving, of else be prepared to plough and sow annual and biennial species every two years. What is really required, then, is a good type of a highly palatable annual and a true perennial that will carry on after the annual has run its normal course. For seed-production purposes, of course, annual rye-grass and perennial rye-grass should never be sown in the same paddock. Italian Rye-grass (Lolium multiflorum). Of the. three types of annual rye-grasses under consideration Italian rye-grass is far and away the most important for New Zealand conditions. It is the basis of all temporary pastures and should be included in all short-rotation pastures in amounts relative to the duration of that pasture. . As a component species in the permanent pasture it affords an early bite, and, if kept well in hand by management,. has little or no detrimental effects on the establishment of the perennial species in the mixture sown. .

Italian rye-grass is suitable for both autumn and spring sowings, and it is one of the most reliable stock crops that can be sown as a supplementary winter and early spring fodder. If sown along with broad red clover, two-year temporary pastures are possible and extremely profitable. Such a pasture gives wonderful winter and early spring grazing. In the peak of the spring production it may be .cut as a hay or ensilage crop, and the red clover aftermath is excellent for summer grazing or as a second clover hay crop, or as a special red clover seed crop. For such a pasture 30 lb. of Italian rye-grass and 6 lb. of broad red clover is recommended.

Western Wolths Rye-grass (Lolium multiflorum var.)

True Western Wolths rye-grass is quicker to establish but is shorter lived than Italian rye-grass. Its maximum value is for autumn sowing specifically for rapid early winter, winter, and spring feed. Its recovery after six months’ grazing, or after an. ensilage or hay crop, is extremely poor, and the six months’ period must be regarded as its period of maximum production. True Western. Wolths is more erect in growth than Italian rye-grass ; it tillers considerably less, and resembles more the cereal than does Italian rye-grass. It is quicker-maturing in the spring, and if spring sown it is inclined more to bolt away to seed rather than to leaf. For this reason Italian ryegrass • is much to be preferred to Western Wolths for spring sowing. The experience of New Zealand farmers may not be in entire agreement with this statement, but it will no doubt come as a surprise to many to know that what they have been sowing as Western Wolths is Italian rye-grass, or a mixture of Italian rye-grass dominant with some Western Wolths. So far as the writers can learn as a result of their strain investigation work, there is little or no genuine Western Wolths on the New Zealand market to-day, and it is highly doubtful, provided Italian rye-grass true to name and type is available, whether Western Wolths has a really important role in New Zealand. It will be seen from Table 1 that of eighty-nine lines sent in as Italian ryegrass 25 per cent, were dominant Western Wolths, and 67 cent, dominant Italian ; whereas of thirty-two lines sent in as Western Wolths 22 per cent, of these were dominant Western Wolths and 69 per cent, dominant Italian. From this it will be apparent that as the trade stands at present, commercial lines of Western Wolths and Italian rye-grass may each be served out of the same sack so far as any difference between the two is concerned.

Wimmera Rye-grass (Lolium subulatum). Wimmera rye-grass is extensively grown in Australia, where it is regarded as an important grass for those soil types where short periods of high production alternate with severe periods of drought. Wimmera rye-grass is extremely rapid to establish from seed, it makes a moderately large bulk of fodder, and is the earliest-maturing type of rye-grass yet tested in New Zealand. Its life of useful growth is extremely short, an almost entire death of the sward taking place after the second cut of herbage. Wimmera rye-grass would appear to be an excellent example of a plant selected by the forces of the environment to qualify for a place

within that environment. The Wimmera rye-grass belts in Australia are essentially drought susceptible areas of fertile soils during a few months of the year when there are sufficient rains to make that fertility available. A plant to exploit such short periods for possible growth must establish rapidly, grow rapidly, and come to maturity rapidly, so that it may ripen and shed its seed prior to the cessation ■ of growth. The seed tides over the difficult drought period, however long, and springs into life again as soon as rains fall. A perennial species under these conditions would perish; and . slower-maturing annuals, such as Italian rye-grass and Western Wolths, that did not ripen their seed during the short growing period would also perish in so far as no mature seed would be produced and shed before the drought began in earnest. There is possibly no soil-type in New Zealand where the growing season is so short that the long-maturing strains of annuals such as Italian cannot ripen their seed, and hence it is obvious that there is no place in New Zealand for such early-maturing and . such short seasonal-growth annuals as Wimmera rye-grass, when annuals of a longer leaf-producing period will thrive.

There is also an important ecological fact to be borne carefully in mind in relation to annuals such as Wimmera rye-grass, and possibly subterranean clover. These annuals are really high producers, and high production is possible only when such annuals are supplied naturally or artificially with a plenteous food supply. Many of the Australian soils are what are termed self-mulchingfree soils that break into powder when dry, rather than cake like cement as in the case with many soils during a dry period. In the Australian self-mulching soils the limiting factor to growth is moisture. When rain falls these self-mulching soils are highly fertile, and they remain fertile while moisture is present. Because an annual plant does well under such conditions it does not necessarily follow that it will do well when sown out on dry hard soil conditions, nor would it be expected to re-establish from shed seed wherever the self-mulching conditions are absent. If it- did successfully re-establish itself its subsequent growth would be stunted and the production low. This point is particularly stressed in view of the possibilities of importations of Wimmera rye-grass for the poor hard soils in New Zealand. There is no soil-type in New Zealand known to the writers where Wimmera rye-grass would prove superior to Italian rye-grass. Wimmera rye-grass in our trials at Palmerston North is the poorest rye-grass yet tested. It is less persistent even than the New Zealand bad false perennial. - Strain Trials. Strain investigation into the types' of Italian. rye-grass was commenced in 1928 at the Plant Research Station, Palmerston North. It has been the usual practice to sow all lines in 15-link rows. For the first , year this method is quite reliable for classification into types and for measuring hay yields.. For periods of more than a year the method is not suitable, as the less persistent types of plants die out and the more persistent types tiller out and fill up the empty spaces. For this reason plots have been sown and single plants have been put out for trials lasting more than a year.

■ Up to the present time . 148 lines have been tested. Very few lines tested have proved to be anything like purely of one type, the only ones approaching type purity being seven lines of Wimmera rye-grass and two lines of Western Wolths type, one of these being a . line of Garton’s Express rye-grass and the other a single-plant selection made near Auckland. The variation in type from both, line to line and within each line is very wide. The following table shows the variation in type of lines which were received as Italian rye-grass and Western Wolths : —

. This table definitely shows that there is virtually no difference between commercial Italian rye-grass and commercial Western Wolths, and that a purchaser has no guarantee as to which he is getting when buying one or the other. ■ Yield and persistency trials have been carried out in rows and single plants, and Table 2 gives the relative value of these types. Ordinary Italian is placed at 100 in each case.

This table clearly indicates the superiority of the Italian rye-grass over the Western Wolths type where one to two-year pastures are laid down, the Western Wolths producing more than the Italian type in the first six months only. The Wimmera rye-grass for the first two months probably outyielded both Italian and Western Wolths, but the poor recovery after cutting minimizes its value where the climatic conditions suit Italian rye-grass and Western Wolths.

Single-plant Study. Twenty plants of each of thirty-one lines were put out as spaced single plants for the purpose of analysing the plant types of various lines. The plants were placed in three wide groups as follows :— (1) Western Wolths type : Open, quick-maturing, free-seeding type. This type gave a good yield to begin with, but after seeding the majority of the plants died.

(2) Italian rye-grass type : Dense,- later-maturing type. Very leafy. Quite a good seeder. Recovered well after first and subsequent hay cuts. (3) False perennial -grass as impurities These plants ranged from a good false perennial to the worst false perennial, some of which resembled false Italian rye-grass rather than false perennial.

An analysis of these types in all lines tested as single plants gives the following average percentages of the dominant types that occur in a composite lot of commercial samples : Italian rye-grass, 63 per cent. ; Western Wolths, 19 per cent. ; false perennial, 18 per cent.

-■ Table 1 indicates, however, that individual lines sold as Italian rye-grass may either be dominant Italian, dominant Western Wolths, or dominant false perennial, and this is true also of Western Wolths. There is no doubt that it is just as important for the farmer to be able to buy, and the seed-merchant to handle, the various annual rye-grasses with the same degree of confidence as they can now buy and handle perennial rye-grass under certification.

Work is now in hand to locate good, types of Italian rye-grass within New Zealand and from overseas, and to work up good strains for distribution later under certification. So far, it must be said that the New Zealand strains are not so satisfactory in general from a type point of view as those secured from overseas, but the number of lines tested from overseas is too small for making definite comparisons. Station-bred lines from the Welsh Plant Breeding Station are doing well in New Zealand, and reports from Great Britain would indicate that the Welsh-bred strains are also doing better in Great Britain than the New Zealand strains. This is not to be wondered at in view of the strain analysis shown above.

* Surviving plants include many showing poor vigour at this stage.

• Sample sold — Percentage of Lines dominantly of Western Wolths Type. Percentage of Lines dominantly of Italian Type. •Percentage of Lines dominantly False Perennial; Number of Lines . tested.. Italian .: . \ . .. . 25 - 67 . . ... 8. 89 Western Wolths 22 ■ 69 .9 - 32

Table 1.—Showing Type Analysis of Commercial Lines sold respectively as Italian Rye-grass and Western Wolths Rye-grass.

' - Type. First Six Months Hay Yield. Recovery after First Hay Cut. Second Cut - —Hay Yield. Percentage of Death after First Year.* Italian IOO IOO IOO. 4 Western Wolths 128 32 63 - 51 Wimmera . . .. No data 1-8 0 IOO

Table 2.Showing relative Behaviour of Annual Rye-grass Types over a Period 0 Twelve Months..