October 4, 1893.] 



Garden and Forest. 



411 



GARDEN AND FOREST. 



PUBLISHED WEEKLY BY 



THE GARDEN AND FOREST PUBLISHING CO. 



Office : Tribune Building, New York. 



Conducted by T" . . Professor C. S. Sargent. 



ENTERED AS SECOND-CLASS MATTER AT THE POST OFFICE AT NEW YORK, N. Y. 



NEW YORK, WEDNESDAY, OCTOBER 4, 1893. 



TABLE OF CONTENTS. 



PAGE. 



Editorial Article : — The Preservation of Soil-moisture 411 



The Benton Harbor Melon Industry Professor L. H. Bailey. 412 



California Railroad-station Gardens Charles H. Shinn. 413 



Foreign Correspondence : — Lilies at Kew George Nicholson. 413 



Plant Notes : — Nymphaea tuberosa. (With figure.) 415 



Cultural Department: — Autumn Planting E. O. Orpet. 415 



Single Dah lias W. E. Endicott. 41 5 



House-plants J. N. Gerard. 416 



Vegetable Notes C. E. H. ^\^ 



Correspondence : — Dahlias not Blossoming John Chamberlain. ^17 



Spring Flowers in Autumn y. E. Learned. 417 



Hemlock in Minnesota H.B.Ayres. 418 



Recent Publications 418 



The Columbian Exposition : — Plants around the Lagoons at Jackson Park, 



J. G. Jack. 419 

 Brevities Professor L. H. Bailey. 419 



Notes..... 420 



Illustration: — Nymphaea tuberosa, Fig. 62 416 



The Preservation of Soil-moisture. 



IN our issue for July 5th it was stated that the approved 

 modern practice among farmers and gardeners is to 

 stir the surface of the soil in order to preserve the soil- 

 moisture to be used by the roots of the crops. The theory 

 upon which this practice is based is, that water rises freely 

 through a well-compacted soil by capillary action, and when 

 it reaches the surface it passes off into the air in the form 

 of vapor. When that surface is stirred, the capillary con- 

 nection with the moist soil below is measurably broken, 

 and although the layer of soil which has been stirred gives 

 off its water more rapidly at first because the surface ex- 

 posed to the air is increased, this layer becomes an effec- 

 tive mulch when fairly dry, and thus checks the evapora- 

 tion of the water which rises from below. 



Since the publication of this article we have observed in 

 some agricultural papers that, while the practice is not con- 

 demned, the theory is disputed. It is argued that if one 

 wants to dry soil for any purpose he naturally keeps stir- 

 ring it, and that the more any soil is stirred the more 

 quickly it dries out. The fact that a certain layer of the 

 soil is called a mulch does not make any material differ- 

 ence between that portion and the part that lies under it. 

 That surface tillage prevents the waste of moisture is said 

 to be a fallacy which common observation disproves ; for 

 if a man walks across a piece of plowed ground it is well 

 known that his foot-prints will remain moist long after the 

 surface of loose soil around them is dust-dry. Now, this illus- 

 tration rather corroborates than disproves the theory. 

 The moisture in the foot-prints plainly comes from water 

 below the surface. Plainly, too, as soon as the water 

 reaches the surface it begins to evaporate. The foot-prints 

 remain damp, therefore, because the water rises there faster 

 than it passes off in invisible vapor ; that is, the foot-prints 

 are damp because the soil-water is being more rapidly lost 

 at that point than in the surrounding field. In some most 

 interesting experiments made in the Wisconsin Station two 

 years ago it w^as shown, among other things, that where a 

 heavy roller is passed overplowedground the rolled ground 



contains less w^ater than that which is not rolled, the dif- 

 ference in percentage of moisture being greater when three 

 or four feet of soil are included in the sample tested than 

 when a depth of but two feet is examined. 



But, as we stated in the article alluded to at the outset, 

 some of the most difficult problems in physics are involved 

 in the movements of water in the soil, and we have much 

 to learn. The first practical question which demands a 

 decisive answer is. How deeply should the surface be dis- 

 turbed.? Plainly, the mulch can be too thin ; that is, culti- 

 vation can be too shallow to produce the best effect. The 

 consideration of this point is suggested by the Report of 

 the Wisconsin Experiment Station for 1892, which has just 

 come to hand. In an experiment there recorded one culti- 

 vator was set so as to slice off and lay back upon the sur- 

 face rather less than an inch of earth at each cultivation. 

 Another one was made to penetrate to a depth of three 

 inches. The soil experimented on was a well-drained 

 clayey loam, and at planting-time the water-table was four 

 feet below the surface, and when the corn was cut it was 

 from five to six feet below the surface. Corn was planted 

 in rows three and a half feet apart, and strips three row^s 

 wide were cultivated with the two implements alternately. 

 On August 27th the result showed considerably more water 

 in the samples of soil taken from the plats which had been 

 cultivated three inches deep than from those which had 

 been cultivated less than one inch deep, and a still greater 

 difference was found in similar samples taken September 

 i6th. This seems to prove that while cultivation to the 

 depth of one inch may do some good, it does not preserve 

 as much water in the soil as if the field was cultivated to a 

 depth of three inches. It is possible that for many crops 

 three inches would be too deep, because of the danger of 

 excessive root-cutting, and the actual depth to which the 

 ground should be stirred in any case should vary to meet 

 different conditions. 



What we wish to call attention to particularly, however, 

 is the fact that the difference of the quantity of moisture 

 under the two kinds of treatment was greater in the fourth 

 foot than at any point above it. This shows the important 

 truth that different ways of cultivating the surface affects 

 the quantity of water to and beyond the depth of five feet — 

 that is, throughout the entire depth occupied by the roots 

 of cultivated crops. In another part of the same report it 

 is shown that the ground-water oscillates every day appa- 

 rently in sympathy with the changes of temperature. It 

 had been already demonstrated at this station that when a 

 plowed surface is compacted by rolling, the ground warms 

 more rapidly and more deeply than it does when it is cov- 

 ered with a mulch like that produced by surface-tillage. It 

 is also show^n that when the soil becomes warm its w^ater- 

 holding power decreases and the capillary water drops to 

 a lower level. When the temperature falls the water is 

 lifted higher, so that even the tile drains on the farms of the 

 Wisconsin Experiment Station discharge water faster 

 or slower as the soil warms or cools. In addition to the 

 fact, then, that by surface-tillage evaporation is dimin- 

 ished, we have the other important one that this cultiva- 

 tion keeps the soil below the surface cooler, and in this 

 way strengthens its capillary power, so that less water 

 which falls as rain percolates downward out of the reach 

 of root-action. Besides this, the stronger capillary force 

 helps the movement of deep soil-water upward and 

 through longer distances, so that more water in a dry sea- 

 son becomes available for growing crops. 



As to the practical use of experiments of this sort there 

 can be no question. We have before stated that in most 

 of our agricultural lands throughout the entire season evap- 

 oration from any given area is about as great as the rain- 

 fall, so that it is probable that during the growing season 

 of most crops evaporation largely exceeds the rainfaU. Pro- 

 fessor King, in the report to which we have just alluded, 

 states that we rarely have water enough in our soil under 

 natural conditions to realize even approximate possible re- 

 turns from our lands. This shows why irrigation, wher- 



