For February, 1920 



67 



methods to a great extent enable gardeners to look upon 

 a strict rotation of crops, so far as it relates to plant 

 food, as of secondary importance, although even in this 

 relationship it must not be ignored entirely. The farmer 

 has to arrange his rotation to fit as far as possible the kind 

 of crops the land is naturally best adapted to insure, in 

 a run of seasons, the most profitable results. The me- 

 chanical condition of a soil, for instance, whether sandy 

 or clayey, causes it to be less fitted for some crops than 

 it is for others ; and there are also other considerations 

 outside soil which have a bearing upon a farm rotation. 



CROP ROTATION IN THE GARDEN 



We cannot follow the same procedure in cro]iping a 

 garden. Some consideration can certainly be given to 

 what our soil and climate will especially favor among 

 garden crops, but, notwithstanding this, the gardener has 

 to grow something of everything and he cannot restrict 

 his operations to such crops as the land is particularly 

 adapted for, but he must endeavor to render his garden 

 capable of carrying more or less of all the vegetables and 

 fruits that find a place in household requirements, and 

 which it may be possible to grow in his climate. That 

 sometimes failures occur at certain points is inevitable, 

 nevertheless his aim will be, and must be. of a somewhat 

 universal kind. .\t the same time in the case of a garden 

 which varies in its mechanical condition, one would ar- 

 range to have ])Otatoes. for instance, upon the lightest and 

 most sandy portion, and cabbage and cauliflowers u]>on 

 that containing the most clay. 



As regards the natural mineral constituents of a soil. 

 a gardener can to a great extent, however, afford to ig- 

 nore in some ways a rotation inasmuch as he has more 

 power to nullify untoward conditions than the farmer : 

 by the proper use of the spade and other hand imple- 

 ments, he can give his garden deeper and more thorough 

 cultivation than is either practicable or profitable by the 

 use of farm implements. A gardener in growing a little 

 of everything, ])erhaps only one row at a time of anv one 

 sjiecies, can give a particular species more of what it re- 

 quires most of ; for instance, a few handsful of fine bone 

 meal scattered along the line before sowing peas and 

 beans will give these just the phosphate they ref|uire in a 

 position near at hand to them. In any case the manuring 

 of a garden should be u])on a more extensive and more 

 fre(|uent scale than is practicable in farming, and a well- 

 handled garden always contains considerable reserves of 

 avail.'ible |)laiit food. 



TIIH VALL'F. Ol' MAMKIXC; 



There is a point related to manuring which is indirrctK- 

 connected with our subject. 



Roth farmers and gardeners are aware nf ilic great 

 \alue of stable manure; it is for all practical pur]ioses a 

 well balanced food, although it ma\- vary in the percentage 

 of its constituents according to what the animals have been 

 fed upon and as to whether they are being grown, worked, 

 or fattened, and there is nothing so effective in the pro- 

 duction of vegetables. It is also beneficial in adding 

 humus, and in bettering the mechanical condition (if both 

 heavy clays and lii^ht sands. There is. however, some- 

 thing connected with it which cannot be explained l)v the 

 combined effects of the plant food and hunms it adds to. 

 and its mechanical effect upon, the soil. 



Last month we drew an analogy between the feeding 

 of plants and the feeding of animals, and it was ])ointed 

 out that in the ca.sc of the latter it is ncces.sarv that their 

 food contain some, at present unknown, vital principles to 

 which the ternt "\'itann'nes" has been given. It was fur- 

 ther stated that there ajipears to be considerable evidence 

 hcmi the results of laboratory experiments and in other 

 directions to show that some accessory substances acting 

 m a similar way are necessary to plants, and that there 



is no doubt that the greater and more lasting effect of 

 stable manure and other animal refuse is due to the exist- 

 ence of this substance or substances. 



It seems worth while in this connection to allude to one 

 of the Rothamsted experiments in the field. 



A plot of ground was taken to which stable manure was 

 annually applied for twenty years, from 1852 to 1871. 

 The eft'ect of the stable manure continued to increase for 

 the first thirteen years : it then increased no more but re- 

 mained at its high level. In 1872 the stable manure was 

 discontinued. Upon this plot the same crop has been 

 grown from 1852 down to the present time, and although 

 the yield has gradually fallen since the manure was dis- 

 continued, it is still thirty per cent higher than another 

 plot alongside of it which has been growing the same 

 crop all the time but has had no manure whatever, al- 

 though in other respects treated similarlv. Tliis experi- 

 ment proves several facts, but the only one which we need 

 consider now is the strikingly lasting character of stable 

 manure as well as the value of organic manure in building 

 up a soil. 



In these days stable manure is difficult, and in some 

 localities almost impossible, to obtain, and therefore one 

 is not always able to get sufficient to manure the entire 

 garden eacli year. In this case its application should be 

 rotated, .so that the entire garden will at lea.st get a dress- 

 ing of stable manure at more or less frequent intervals. 

 We have in a previous month pointed out that the short- 

 age of stable manure can in some respects be made good 

 l)y the use of stock-yard manures and the tuming under 

 of green crops. .At any rate in j)lamiing tlie work of the 

 garden the question of the rotation of manure has some- 

 times to be considered. 



IMI'OKT.VNCE OF ROT.XTIOX TO CO .MEAT TESTS 



C nming back to the rotation of crops, this in a vegetable 

 garden is really more important in connection with insect 

 and fungus pests than with anything else, and this im- 

 portance is greater in respect of some crops than with 

 others. 



In these days insects and fungi of nunu-rous species 

 give us an increasing amount of trouble, and upon a place 

 of any size one man can find plenty to do in devoting his 

 whole time during the growing season to the work of 

 spraying, etc., both for prevention and cure. In a vege- 

 table garden a rotation can be made as regards some crops 

 ail indirect means of preventing and reducing the ravages 

 of "nests." 



While many of these economic parasites u.se several 

 species of plants as hosts, yet there are certain of them 

 which attack, so far as our gardens are concerned, only 

 one family or species. Before, or at the beginning of, 

 iln' winter season these i)ests go into a dormant stage 

 and hibernate in some form or another until the follow- 

 ing growing season. Xaturally-. and invariably, they 

 pass tiie Winter near where they lived during the Sum- 

 mer. ,-ind it therefore follows that if we grow a crop upon 

 the ground occupied bv the same crop during the pre- 

 ceding year it will be more liable to attack bv its .special 

 liests than if it occupied a position some distance away 

 v\hich had not grown that crop for several seasons. 

 ihis is especially true in those cases where the j^ests live 

 and work under the surface and attack the plants' roots. 



One of these latter is a fungus known as Club-root 

 which attacks, more or less, all members of the Crucifer- 

 ous family and is especiallv eft'ective in damaging cabbage 

 and cauliflower. File fungus which produces Club-root 

 belongs to the .\fyxoiii\rctrs, or "slime fungi." which 

 live u[)on deca\ing vegetable matter. This fungus rami- 

 fies within the tissues of the roots of attacked plants, 

 cnusing first a swelling on the roots the interior of which 

 afterwards liecomes full of slimy matter. Eventually 



