352 STATE BOAED OF AGKICULTUEE. 



of succeeding crops; while another clas?. which have narrow leavp.s and a small 

 amount of foliage, are incapable of obtaining a sui^cient supply of nitrogen 

 from the air for full development. This distinction is forcibly expressed by 

 Ville of France, who divides plants into nitrogen ijvoducers and nitrogen con- 

 sumers. Red clover may be taken as the type of the nitrogen producers and 

 wheat of the nitrogen consumers ; the one is broad-leaved, has abundance of 

 foliage, and can arrive at a high degree of development without the use of nitro- 

 genous manures; the other is strap-leaved, has little foliage, and cannot reach 

 a satisfactory development without a supply of nitrogen beyond what the air 

 can afford ; it demands an accumulated supply of nitrogen in the soil. The 

 pressing demand of all cereal crops is an adequate supply of available nitrogen 

 in the soil. This may be furnished by barnyard manure, by nitrates, salts of 

 ammonia, guano, etc., or it may be furnished by growing crops which have a 

 special power of accumulating nitrogen from the air, burying these in whole or 

 in part in the soil and thus storing up in the soil an amount of available nitro- 

 gen for the use of future crops. The power of one crop thus to store up mate- 

 rials for the growth of future crops is a fact that lies at the foundation of suc- 

 cessful agriculture. The plaster which is so abundant in our State has a mar- 

 velous power of promoting the growth of clover, and the clover is the best pos- 

 sible preparative crop for wheat, which is the cash croj) of our State. Plaster 

 and clover become jplenty and casli in the hands of a good farmer on a kindly 

 soil. George Geddes told me that he had a field which had been constantly 

 cropped for 40 years which had not in that time received a single load of ma- 

 nure, but that its fertility had been kept up by plaster and clover ; that the 

 field was then in as good heart as neighboring fields -svhich had received liberal 

 dressings of barnyard manure. 



But the beneficial influence of green manuring is not confined to the accumu- 

 lating of combined nitrogen. Fresh vegetable matter, from the large amount 

 of Avater which it contains, undergoes rapid decomposition when buried in the 

 soil ; in this respect it is much superior to dry vegetable matter, such as straw. 

 This rapid decomposition imjoarts a tendency to decompose to other materials in 

 the soil. Inert humus in the soil is converted into more active form ; it even 

 acts upon the inert mineral matter in tlie soil, converting it into the soluble and 

 active form, thus securing an increased amount of mineral matter to sustain 

 plant growth. By green manuring we thus secure an increased amount both 

 of organic plant food and of inorganic or mineral plant food. If it does not 

 directly add any thing of mineral matter to the soil, it does what is equally as 

 important, viz. : it converts inactive and useless mineral matter into a form 

 available for the use of growing plants. It may be called the masticator of the 

 soil. 



The roots of growing plants also exert a corroding and decomposing influence 

 upon the inert materials of the soil. Sachs demonstrated this fact by taking- 

 polished plates of marble, dolomite, phosphate of lime, gypsum and glass, plac- 

 ing these in quartz sand which was kept moist. In this sand seeds of peas, 

 Indian corn, squash, and wheat were planted and suffered to grow. The roots 

 penetrated the sand and coming in contact with the plates below branched out 

 horizontally on their surface. After a time the plates were removed and exam- 

 ined, when the plates of carbonate of lime and magnesia and the phosphate of 

 lime were plainly corroded where tliey had been in contact with the roots, so 

 that the course of the roots could be traced without difficulty, and even the 

 action of the root hairs was manifest as a faint roughening on each side of the 



