CHAPTER XIII._Science and Practice in Farm Cultivation

ON THE IRRIGATED MEADOW.

Irrigation, as a means of increasing the amount of pasturage, is so

important a process that it may be well to describe it in this place.

For a perfect irrigated meadow, we should have full command of water

whenever it may be required. This water should be capable of flowing

through, not of pouring over, and standing on the land,—this latter

being flooding. The drainage should be so perfect that the land will be

sound enough for us to walk over in the dry in a few hours after the

water has been turned off.

Where these conditions can be secured, irrigation will be found most

useful, not only in augmenting the supply of grass, but in producing it

so much earlier than in the higher meadows that the farmer hereby gets a

fresh green pasture, of great utility, especially in fattening and

bringing on early lambs. From these circumstances it follows, that

although some land is occupied in the water-conduits, yet the value is

so far increased that meadow at 30_s._ per acre before irrigation has,

under one’s own eye, become worth £5 per acre in four years. There are,

however, some necessary expenses in setting out the work, making

floodgates, &c., the extent of which will of course depend upon the

nature of the ground. In Gloucestershire, on the banks of the Churn,

where irrigation has been successfully carried on for years, there is a

permanent cost of about 6_s._ an acre for keeping the works in order,

and charges of the “drowner,” the name given to the man who overlooks

the works, in some instances of several proprietors or tenants.

A peculiarity in irrigated meadow of the best quality is, the general

absence of coarse grasses on the one hand, and of any plants other than

grasses on the other; hence, then, good succulent and nutritious herbage

is the rule, and anything that can be otherwise described is the rare

exception. Indeed, so much is this the case, that a bit of coarse

grass—such, for instance, as _Aira cæspitosa_ (Tussac Grass)—making

successful growth in any part of the meadow, is at once an evidence of a

stagnation of water at that spot—a condition that a clever drowner at

once looks to when he has discovered it.

As an evidence of the changes which go on as the process succeeds, as

well as of their nature, we give the following as the tabulated result

of the irrigation of half of a meadow whose slope was too great to allow

of the whole being operated upon. From these it will be seen that the

proportionals of different pasture plants before and after irrigation

offer a material change; and it may be added, that in some cases, what

would otherwise be a bad and useless grass, may become succulent and

useful from the beneficial action of water. One of this kind is the

_Agrostis stolonifera_ (Fiorin Grass), which is in arable couch-grass

weed, but in the irrigated meadow it becomes of a fine green colour, is

nutritive in quality, and will bear with any amount of clipping. It may

here, too, be remarked that in cases where only a part of a meadow can

be irrigated, good accrues to the whole, as in depasturing the whole is

ranged over by our cattle and sheep.

We here give the following

TABLE OF CHANGES IN GRASSES AND OTHER PLANTS UNDER IRRIGATION.

+----------------------+------------------+------+--------+--------+

| | | --- Irrigation. --- |

+----------------------+------------------+------+--------+--------+

|Meadow Foxtail Grass |Alopecurus | 1 | 2 | 3 |

|Field Meadow Grass |Poa pratensis | 2 | 3 | 4 |

|Rough-stalked ditto | „ trivialis | 1 | 2 | 1 |

|Quaking Grass |Briza media | 2 | 0 | 0 |

|Dogstail Grass |Cynosurus | 2 | 1 | 0 |

|Hassock, or Tussac |Aira cæspitosa | 1 | 0 | 0 |

|Marsh Bent |Agrostis | 1 | 2 | 3 |

|Cocksfoot Grass |Dactylis glomerata| 1 | 2 | 3 |

|Yellow Oat-grass |Avena flavescens | 2 | 3 | 3 |

|Soft ditto | „ pubescens | 1 | 1 | 1 |

|Meadow Barley |Hordeum pratense | 1 | 2 | 2 |

|Perennial Rye-grass |Lolium perenne | 2 | 4 | 6 |

|Meadow Crowfoot, or |Ranunculus acris | 1 | 3 | 1 |

|Bulbous ditto | „ bulbosus| 3 | 1 | 0 |

|Narrow-leaved Plantain|Plantago | 3 | 1 | 1 |

|Broad-leaved ditto | „ asiatica | 3 | 0 | 0 |

|Dutch Clover |Trifolium repens | 2 | 0 | 0 |

|Broad Clover | „ pratense | 1 | 2 | 2 |

|Common-beaked Parsley |Anthriscus | 1 | 2 | 1 |

+----------------------+------------------+------+--------+--------+

The general conclusions from this table are, that large and innutritious

herbage is, for the most part, destroyed by irrigation, and its place is

supplied by grasses; hence, then, the increased value conferred by the

regulated action of water is due to an increase in quantity and quality

of the grasses, added to a much more certain, as well as early,

production of these. Of course the districts best adapted to irrigation

will be valleys of denudation, the centres of which are occupied by more

or less copious and rapid streamlets. Some of these valleys in the

Cotteswolds having been scooped out of the oolitic freestones, have left

the spoils of the rock as a gravelly deposit, sometimes on the lias, at

others on the fuller’s earth, and then on the Oxford clays; so that,

stiff as these soils would be by themselves, they now only tend to throw

out the waters by natural drainage, which are again conducted over the

porous gravels through which they flow with great regularity; thus

fertilizing what would otherwise be but a scanty thin-soil herbage, and

to such an extent that early depasturing, haymaking, and later pasturage

(_lattermath_) are the rule year by year.

These circumstances make water-rights of great value, and which, if not

in possession, are secured at a fixed charge per acre; this, however, is

usually included in the expenses, which, as before stated, are covered

by about 6_s._ per acre.

Before concluding this chapter, we must say a few words in reference to

flooded meadows. These will be found on the banks of the larger rivers

or on streams of sufficient importance to be called rivers, as

distinguished from brooks or streamlets. Here the flooding is caused by

the water overflowing the banks, as the result of sudden thaws or an

unusual quantity of rain. Here then the flood is not under control, and

as it may happen at any and all times of the year, the grass may be

spoiled by being covered with silt and drifted materials, or even the

hay may be carried away by the flood.

These river flats, then, have seldom the requisites for carrying on

irrigation, although the waters are of course more abundant than those

supplied by the smaller streams; for even if we could by embanking so

far control the water as to get it over the field when we might wish,

yet alluvial flats like those of much of the Thames and Severn would not

readily drain.

From facts like these it will at once be seen that there is a wide

difference between irrigation and flooding; and we have hence

endeavoured to separate what is too often confounded.