Pasture.

Pasture. A pasture may be defined as a crop of mixed grasses and clovers, or other leguminous plants, intended for purposes of grazing. Such a crop usually occupies the land for many years, and is then called permanent pasture. The chief benefit accruing to the farmer is that the mixed plants occupy the land more completely than the same constituents grown in separate plots. The various species of the mixture overlap and foster one another; thus produce is increased, and quality of herbage improved. From this point of view, a pasture is an agricultural device for increasing the amount of land at disposal, since from a single acre of mixed crop as much produce may be obtained as from, say, $1\backslash frac\{1\}\{2\}$ acre laid down under pure sowings.

The chief plants used in Britain for forming pasture may be classified thus:

(A) Top Grasses.—Cock's-foot (Dactylis glomerata), Meadow Fescue (Festuca pratensis), Meadow Fox-tail (Alopecurus pratensis), Timothy (Phleum pratense), Italian Ryegrass (Lolium italicum).

(B) Bottom Grasses.—Crested Dog's-tail (Cynosurus cristatus), Fiorin (Agrostis stolonifera), Hard Fescue (Festuca duritucula), Rongh-stalked Meadow Grass (Poa trivialis), Smooth-stalked Meadow Grass (Poa pratensis), Wood Meadow Grass (Poa nemoralis), Sweet Vernal (Anthoxanthum odoratum), Yellow Oat-grass (Avena flavescens), Perennial Ryegrass (Lolium perenne).

(C) Clovers and Leguminous Plants.—Alsike Clover (Trifolium hybridum), Red Clover (Trifolium pratense), White Clover (Trifolium repens), Trefoil (Medicago lupulina), Bird's-foot Trefoil (Lotus corniculatus).

This list includes several species which are not permanent, but of short duration, as Timothy, Italian and perennial, ryegrass, red and Alsike clover, and trefoil. Timothy lasts from four to six years, and at times even longer. Perennial ryegrass has a very misleading name, inasmuch as it may die out in three or four years; in other cases, where seeding is prevented, the ryegrass may become, to all intents and purposes, a perennial plant. The reasons for including short-lived constituents in permanent pasture are obvious. They not only give increased produce during the first years of the lea, when the permanent species are slow in coming forward, but hold possession of land which would otherwise be bare, and thus keep out worthless plants. Place is made for the expanding perennials by the short-lived species which gradually die out. This must be carefully borne in mind when fixing the proportion of short-lived plants in a mixture.

The following are the leading principles according to which the various constituents of a mixture are proportioned: (1) To obtain maximum produce, the land must be filled with roots as thoroughly and completely as possible. This is accomplished by incorporating deep-rooted and shallow-rooted plants in due proportions. If, for example, a soil is 3 feet deep, and the roots occupy merely 1 foot of this depth, two-thirds of the land is, evidently, lying idle and unutilised, not for one year, as when under an ordinary crop, but for a long series of years in the case of a permanent pasture.

(2) The nutritive value of the mixed herbage depends upon the relative proportion of grass and clover: the albuminoid ratio increases with the amount of clover. For a permanent pasture good proportions are clovers, 20 to 30 per cent. of total area; grasses, 70 to 80 per cent.

(3) As many species as possible should be represented in the mixture. If one is injuriously affected by drought, another, which revels in drought, is ready to take its place; if one is late, another is early; if one is not relished by the browsing animal, another is, and so on.

(4) Those species which are best and most suitable for the soil should be most largely represented.

(5) Certain species liable to overrun the pasture, or to destroy other good plants, ought to be represented in extremely small proportions. This applies more particularly to ryegrasses (especially

Italian), crested dog's-tail, and smooth-stalked meadow grass.

(6) The short-lived components should not cover more than one-third of the whole land.

According to these principles, a mixture suitable for a wet clay might be proportioned as follows :

Area of the land to be covered by clovers, 20 per cent :

Area to be covered by short-lived grasses, 20 per cent :

Area to be covered by permanent grasses, 60 per cent :

The percentage area of land to be occupied by each component being determined and known, the percentage numbers have to be translated into pounds of seed per acre. To get the number of pounds corresponding to these areas the covering power of each kind of seed used must be known. We assume, as a basis for calculation, that the seed is perfect in quality—i.e. the percentage of purity is 100, and the percentage of germination also 100. According to Stibler, one acre of land is covered by the following amounts of perfectly pure and germinating seeds :

In using these numbers as a basis for calculating mixtures, allowance must be made for seeds which cannot germinate on account of imperfect tillage, and also for the overlapping of the plants when grown in mixture. An allowance of 50 per cent. is found, in ordinary cases, to meet these requirements. The amount of seed per acre actually used in mixtures is, accordingly, the amount calculated for an acre and a half.

The mixture already given for a wet clay soil when translated into pounds of perfect seed per acre (making an allowance of 50 per cent.) is :

By simple proportion pounds of perfect seed can be immediately converted into pounds of commercial seed of any given quality.