66 



GARDENERS' CHRONICLE 



tllllilillininiiii>inniiiiiiiiiiii;iiii:iiiiiiiiiililiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiuii:i>iliNiiiiiiiiiiiuiiiitiiiiiiiiiini|[|iliiiliiiiili»iJ^ [!iii:[;iiiiiti:mi{|iniiin:iiin;ii:iiiniiiiiiit:iin'tMiiiiiiini;iii!!iiii!iiiiiim!miiii!i:iiii:i;ii: iii!:iiii:ii»iiiii:iiiiiiiiiiiliiiiiuillll»liiililil| 



I A Lesson on Some Whys of Crop Rotation | 



1 Being One of a Series of Lessons of a Home Study Course on (iardcninu. Ajjinaimii Ke^ularU in The GARDtNERs' Chronicle = 



I Under the Direction of ARTHUR SMITH | 



iiimiiiiiiillllliiiilliii!iiiiliiiiliiiiiiiiiiiiiiiiiiiiiiiiiiiiiilii:iiii:iiii!iiiiiiNiiiniiiliiiiiiiiilii:iiiiiiiiiiiNiillllliiliil^^ i iiiimniiiiiiiiiiiiiuiiiiiil 



PREPARING FUK AN'U PLAXXING THE SEASOX S CROPS 



With the lengthening days our thoughts are naturally 

 along the lines of planning for the coming season, espe- 

 cially in the way of making out and sending the seed 

 order, so that there will be no delay in taking advantage 

 of the earliest moment that seed sowing becomes possible. 



Those who adopt the excellent plan of keeping a diary, 

 and note weather temperatures, dates of sowing, germina- 

 tion, etc., together with results obtained, are in a better 

 position to review the past successes and failures than is 

 the case with those who trust to their memories alone. 

 Frequently more can be learned from failures than from 

 anything else, especially if we arrive at correct conclu- 

 sions as to their cause. 



Owners of large gardens have room enough to grow a 

 sufficiency of everything for their requirements which 

 their climate will jjroduce : but with smaller areas it is 

 frequently necessary to consider the tjuestion of what to 

 grow and what not to grow, and to divide up a limited 

 space to the best advantage. It is generally a wiser pro- 

 cedure to grow a few varieties well than to attempt a 

 larger number than can be successfully brought to ma- 

 turity upon the space given them. 



In those cases where one cannot produce everything 

 in the way of vegetables required by their household it is 

 better to leave out those articles which deteriorate least. 

 or do not deteriorate at all when sent to the market. For 

 instance, there is not as a rule a great deal of difference 

 in quality between potatoes grown at home and those ob- 

 tained from the market ; whereas under no jiossible con- 

 ditions can we buy peas and beans at all apjiroaching the 

 (|uality of those we can grow for ourselves, and it would 

 therefore he better to secure a constant supply of these 

 latter than to grow potatoes unless we have room enough 

 to produce a sufificiency of all. 



It is well at this season to map out u[)on paper a gen- 

 eral cropping scheme so as to see what amount of space 

 can be devoted to each kind, both in relation to the sec- 

 ond, as well as to the first crop we ])ropose to plant, bear- 

 ing in mind the fact that, generally speaking, two crojjs 

 in a season may be obtained off the same ground, of 

 course leaving out of consideration permanent crops like 

 asparagus ; and even if conditions do not always permit 

 of averaging two crops in a year, we can certainly aver- 

 age three crops in two years off the entire ground not 

 devoted to things which are permanent. 



In making plans, whether in our minds or upon paper, 

 it is worth while to consider the question of rotating the 

 various crops, so that a given species does not occupy 

 the same grounrl in successive years and that an interval 

 of one or more years shall pass before it is grown there 

 again. 



AN UXDERLVING PRTXCIPLE OF CROP ROTATIOX 



One underlying principle of crop rotation is the con- 

 servation of soil fertilit}', and it is, in a general way, more 

 strictly adhered to in connection with farming than with 

 gardening : in fact, very fretjuently farm leases contain 

 clauses stating that certain crops shall not be grown upon 

 the same ground except after certain specified intervals. 



A rotation is the arranging of a succession of crops 

 which will ta.x the soil for plant food in a different man- 

 ner. Some plants require certain elements of plant food 

 in different pro])ortion than others, and in the case of 



nitrogen some do not require it in the soil at all as they 

 obtain it from the air. Peas and beans are among the 

 latter and are designated nitrogen-producing crops ; while 

 corn and cabbage are among those classed as nitrogen- 

 consuming, therefore, bv growing the latter after the 

 former the necessity of adding nitrogen is. to a great ex- 

 tent, if not entirely, obviated. While it may not always 

 be possible to avoid the direct application of nitrogen to 

 some crops in a vegetable garden, yet it is easy so to ar- 

 range a rotation of crops for a farm that it will render 

 direct applications of nitrogen entirely unnecessary. 



\\'hile our cultivated plants recpiire food containing 

 some of all the various elements which are found in vege- 

 table matter, yet they do not all take up these elements 

 in the same proportions ; for instance, there is about eight 

 times more lime in a given weight of cabbage than in the 

 same weight of potatoes, and if we grow the same crop 

 continually upon the same ground we gradually exhaust 

 the soil of the requirements of that crop that are in an 

 available condition, and, unless special fertilizers are 

 added, the time will arrive when that particular crop will 

 cease to produce anything worth while : and in this con- 

 nection we must remember that no excess of one element 

 will compensate for a deficiency in another, or in others. 

 1'. must he emphasized that in speaking of plant food being 

 exhausted it only applies to that which is available, as for 

 all practical purposes no system of cropping will exhaust 

 a soil of its mineral constituents, of which only a small 

 amount is ever in an available state at one time ; there- 

 fore by growing the same crop year after year upon the 

 same ground the available food which that crop requires 

 in the largest quantity is used up faster, and there is not 

 enough of that food to supply its full requirements, and 

 therefore the yield becomes less, but by growing another 

 crop which reipiires less of what the other reejuired the 

 most, opportunity is given for an increase in the available 

 amount of that ingredient. 



Then again, species differ in their methods of seeking 

 nourishment. We can have two distinct plants practically 

 agreeing in their food requirements, yet one might fail 

 where the other would succeed. Suppose, for instance, 

 members of the cabbage family had been grown continu- 

 ously until the soil began to fail, even then we might grow 

 .good crops of ]iarsnips and carrots for the simple reason 

 that they send their roots down into a stratum which the 

 other crops never reached. It is most instructive to bear 

 in mind that, although the parsnip will do well upon soil 

 of which the surface has been more or less exhausted, 

 yet the dry matter of this plant contains thirty-six per 

 cent of .potash, eleven per cent of lime, and twenty per 

 cent of phos]ihate. How does the parsnip obtain its min- 

 eral food in a soil which for other crops appears to be 

 exhausted? Simply by pushing down for it into a mine 

 that has hitherto been but little worked, though the cab- 

 bage might fail in the same plot because the sujierficial 

 stratum had been over-taxed. 



As far as we have gone the subject has been con- 

 sidered in regard to the conserving and making the .great- 

 est use of the natural soil fertility, and these considera- 

 tions have a greater bearin.g upon farming than upon 

 gardening. Gardening is a more intensive branch of agri- 

 culture than farming. In gardens we adoi>t methods of 

 cultivation and manuring which would be impracticable 

 and uniirofitable in connection with farming: and these 



