] '29H 



ENCYCLOPEDIA OF AGRICULTURE. 



SUPPLEMENT. 



production of starch, and the potato remains cither waxy, or, wli.it is worse. soft and watery. Now, a 

 ic\ lew of these facta would lead to the following is regarding the culture of this plant : " — 



8104. 1st. •• There must be an abundant supply ol manure, because, not only must the leaves be quickly 

 developed, but the toll must be in a condition t" yield azote abund uitly, even during the latter period of 



the growth of the plant ; hence, small quantities of active manure v. ill not succeed marly so well with 

 this plant as with the turnip." 



BIOS. 2d, " The manure Deed not be so well prepared, as t t supply of azote is not required 



until some time alter the plant has risen above ground ; hot :! must not lie to., fresh, for fear of retarding 



the development of the leaves, nor too hot, lor tear of acting injuriously on the seed or tuber." 



8106, 3d, ■' We must not give tln> crop too much rich manure, lor 'tear of making a greater demand 



upon the atmosphere than it is capable of answei 

 XI07. 4th, " The plants should be placed far apart, so as to permit of the free increase of the leaves." 



8108. 5th, " As the potato has a spreading root, and the tubers are nearly all developed upon the under 

 surface of tin- tilires w Inch run most horizontally, it is very injudicious to earth u\: the plants, a- this of 



•v renders the roots more perpendicular. Experiment has proved that this practice occasions 

 considerable loss." 



8109. 6th, " To obtain the largest number of tubers, the flowers should be plucked off to prevent the 

 formation of Seed, while every tiling should be done to protect the leaves from injury." 



8)10. 7th, " The soil for the potato should be loose, although this plant will grow in a much greater 

 variety of soil than the turnip. This also depends upon the tubers being a completely developed pi 



destined for the production of a separate individual ; whereas, the bull) of the turnip is for the pur] 



of supplying the plant during the most important period of its growth ; viz., during the development of 

 the seed, with abundance of moisture and nourishment, when growing in a soil which cannot naturally 

 retain these : and tin rehire, it we attempt to grow the turnip upon stiff soil, it either does not flourish 

 at all, or else the bulb is very imperfectly developed, for in this case the soil can supply all that is re- 

 quired, without the as.-ist. one of this artificial reservoir." 



»l 1 1 . Wheat, oats, and barley. " All of the cerealia agree in so many respects, that it will be advan- 

 tageous to consider them together." 



8112. 1st," As they are cultivated for their seed, they are perfectly developed before harvest, and, 

 therefore, exhaust the soil to a much greater extent than green crops." 



8113. 2d, " As their system of leaves is very much less than that of the plants before considered, tie 

 are much more dependent upon the soil even for those elements which larger leaved plants obtain from 

 the air." 



8114. 3d, " As the seed is, in all instances, the most highly azotised portion, and as it is the last part 

 developed, it follows, that these plants require more a general richness ol the soil than a supply of newly- 

 added manure. On this account, it is with propriety, therefore, that they are seldom made to follow- 

 close after the application of manure, but are either preceded by a green crop, or are sown after summer 

 fallow." 



'" These crops differ among themselves chiefly as regards soil and climate ; wheat requiring clay, barley 

 a lighter soil, and oats succeeding pretty equally on all good soils, of whatever texture they may be. 

 The same is the case concerning climate, and the richness of the soil ; — wheat requires the best climate 

 and the richest soil, then barley, and then oats. It is not easy to explain this satisfactorily, for alt 

 we can produce many circumstances which appear to explain the differences in question, more careful 

 examination will prove that they can merely be considered in the light of probabilities, and by no means 

 as certainly ascertained facts. For example, if we examine the ashes of these three plants, we find that 

 their quantities amount proportionally to three, two, and one, wheat containing the most, and oats the 

 least ; and if we examine still further, we shall find that clayey soil is more capable of yielding the in- 

 gredients of these ashes than land of a lighter texture. This renders it probable that one of the causes 

 of wheat requiring clay, depends upon the necessity of a larger supply of these earthy particles ; but 

 accurate calculation also proves, that many plants which grow best on sand remove from it a greater 

 quantity of these very substances than would be required to supply the heaviest crops of w heat. It 

 cannot, therefore, be considered as proved, that the cause of wheat preferring clayey soil, depends upon 

 the greater quantity of earthy matter required for its perfect development, although we may venture to 

 advance as a probability, that it depends upon an increased facility of obtaining this supply. Again, these 

 three crops require a considerable supply of azote during the latter periods of their growth, the proportion 

 being, wheat 2'13, barley T76, oats l-'JG; so that here again, since we know that decomposition proceeds 

 more slowly in clay, and the azote of the manure is hence not so quickly given off, we might argue that 

 clay would be better fitted for wheat Chemical analysis, however, proves in this case also, that some 

 crops peculiarly suited to sandy soils contain a much larger absolute quantity of azote, although it must 

 be admitted that the relative proportion is much less. Our conclusion here, also, must therefore be, that 

 the cause of wheat thriving best upon clay, depends probably upon its receiving azote in a greater degree 

 of concentration." 



81 15. Beans, peas, and other leguminous plants. " Very little can be said regarding these in the present 

 state of our knowledge, as but little particular attention has hitherto been paid to them by the scientific 

 inquirer; and there are so many peculiarities exhibited by them, that it would be very imprudent to 

 risk an opinion upon so meagre a collection of facts. Beyond all doubt these are the most hazardous 

 crops we cultivate, as they are so very much influenced by the weather. Clover, for example, is a plant 

 the success of which we can scarcely in any instance predict, as, no matter what the state of the soil may 

 be, a few days of unfavourable weather may destroy at once all prospect of success. We may, however, 

 notice one fact in this place, although we shall not attempt its explanation, viz., that the nitrates of potass 

 and soda, two very favourite manures, appear to exert au almost magic influence over clover in rendering 

 it much more certain and luxuriant." 



These observations complete Dr. Madden's review of the facts in agriculture, which are already ex- 

 plained by science : he regards them as showing that considerable advances have of late been made, and 

 he hopes soon to see the farmer and the philosopher pressing forward hand in hand in the field of agri- 

 cultural improvement. He subjoins the following tables : — 



I. Table showing the relative nutritive Powers 0/ various Articles of Food, deduced from the Quantity of 

 Azote which they contain. Arranged from M. Boussinguult's Tables. 



* That is to say, that GO lbs. of red clover hay contain as much nourishment as 100 lbs. of common 

 hay, and as 612 lbs. of turnips. 



