THE FARMER'S MAGAZINE. 



435 



NOTES ON MEADOWS AND PASTURES. 



By JAMES BUCKMAN, F.Q.S., F.L.S,, 



Professor op Botany and Geology at the Royal Agricultural College. 



Part IV, 



THE IRRIGATED MEADOW. 



There is no subject connected with pasture-land of 

 greater interest or importance than that of the irrigated 

 meadow ; and we, therel'ore, propose to devote this 

 paper to its consideration. 



Irrigation may be defined as the directing a flow of 

 water, at chosen intervals, through a pasture ; and we 

 shall the more clearly understand this definition by a 

 study of the following, with which it is so often con- 

 founded — namely, flooding, the accidental overflow of 

 the waters of a stream upon a pasture. 



Irrigation, then, is a controllable operation within the 

 limits of its requirements, which may be briefly stated 

 as follows : 



Istly, A stream of water so disposed as to be capable 

 of conduction over the pasture ; and, 



2ndly, A condition of soil and surface that will en- 

 sure an equable and certain flow of the water through 

 the pasture. 



Considerations, then, arising out of these require- 

 ments, would lead us to infer that the rivulets and 

 tributaries to the larger streams, or rivers, afford the 

 conditions most suitable for irrigation, as they are 

 always on a liigher level, and so aff"ord the requisite 

 amount of fall for conduction, whilst the broader rivers 

 flow through the flat country, between, not over, steep 

 banks, which soon overflow on a sudden accession of 

 water or a swollen tide, and thus a flood occurs, which 

 is without control as to its quantity of water, the time 

 of its coming, or the period of its removal. Not always, 

 indeed, is it capable of running back to the river, but 

 must await the slow process of percolation through the 

 substratum, if sufficiently porous ; and, if not, it may 

 possibly go off by evaporation. 



Having, therefore, so far made clear our meaning of 

 the subject of irrigation, we prefer to farthei illustrate 

 the matter by a reference to the system as carried for- 

 ward on the banks of the Churn, the longest tributary 

 of our most important river Thames; end we choose 

 this because the district north of Cirencester, in 

 Gloucestershire, to Cricklade, in Wilts, southwards, 

 ofl'ers one of the best, as it was one of the earliest, sites 

 of irrigative labours. 



The Churn takes its rise from the Cotteswold Hills, 

 which run for miles north and south, from Warwick- 

 shire to Somersetshire; and, being composed of an 

 upper stratum of porous stone in the oolitic rocks, 

 resting on impervious lias clay, these hills offer a large 

 collecting medium for the rainfall of the district, which 

 gushes out at the juncture of the lias and oolite, in the 

 shape of springs, some smaller ones, on the scarp sides 

 of the hills, running along the vales of Gloucester and 

 Worcester to the Severn ; but, as the dip of the strata 

 is from the N.W. to the S.E., or in the direction of the 

 valley of the Thames, that river, consequently, receives 

 the larger share of the Cotteswold watershed. 



The present condition of this valley, then, is that of 

 a winding flat, of greater or less width, between gently- 

 sloping eminences on either side. This flat land is co- 

 vered all over with silt and gravel, which has been 

 deposited there by a former broader stream. The pre- 



sent stream, however, has cut its narrower passage, in a 

 tortuous course, through these shifted materials. Here, 

 then, the very porous nature of such river-flats, and the 

 poor vegetation of the gravelly subsoils, under- natural 

 conditions, offer not only the best circumstances, but 

 the best conditions, for carrying out irrigation ; for the 

 hill-stream is sufficiently rapid, from the amount of 

 fall, to enable its water to be conducted over very wide 

 tracts with great facility ; and the amount of water, on 

 account of the great extent of the porous strata above, 

 is not only abundant, but tolerably equable, the usual 

 flatness of the ground, as left by the wide, brawling 

 stream of past ages, rendering it no difHcult matter to 

 conduct the water over large areas, whilst the porosity 

 of the substratum offers just the conditions for its 

 draining through the pastures. 



Taking these circumstances into due consideration, it 

 is no wonder, then, that in this district irrigation should 

 become a general system, and more especially as the 

 result of the process is to raise the value of land from 

 an average of about 25s. to 100s. an acre as a rent- 

 charge — a difference so great, that some important rea- 

 sons must be at the bottom of them ; and these we shall 

 now consider, under the following heads : 



Istly, The influence of water on grass herbage. 



2ndly, The changes in the kinds of herbage plants 

 under irrigation. 



3rdly, The economic relations of irrigated meadows, 



1. The Influence of Water on Grass Herbage. 



There can be no doubt but that the action of water 

 upon meadow depends upon a variety of circumstances, 

 such as mechanical, chemical, and climatical effects — 

 mechanical, from the power of disintegrating small 

 rocky particles, as well as dissolving mineral matter 

 in general, which the percolation of soft water through 

 the soil in which the herbage grows effects ; che- 

 mical, from the mineral matters in solution, which 

 all running streams possess, to a greater or less 

 extent, thereby materially adding to those raanurial 

 principles which the water has aided to dissolve, so that 

 the removal of an annual crop of hay only creates a 

 partial diminution of these, which are again restored as 

 soon after haymaking as possible, in order to refresh 

 the soil for a quick production of the " lattermath," 

 The plan of operations in the ordering of the " drown- 

 ing," as it is locally termed, is about as follows : 



Beginning in November, the water is let on to the 

 meadow, from time to time, until February. 



The early grass is then eaten off by sheep and lambs, 

 which are usually folded. When eaten to the " bone," 

 water is again directed through the field for a few 

 days ; and it is then " aimed up" for the hay crop. 



This taken, it is again treated with water, if there be 

 a supply — which is not always the case in the summer 

 — for the " lattermath.'' 



That this method of water-action induces a decided 

 climatical effect, can hardly be doubted ; for, as the 

 fluid is in constant motion through, and not over, the 

 herbage, there is no sign of freezing, except in stagnant 

 places, in the most severe weather ; and so, while, all 

 around, the grass may be one uniform brown tint, the 

 part under irrigation is at such times of a lively green ; 



