394 MINNESOTA STATE HORTICULTURAL SOCIETY. 
ments are present in various proportions. No two brands of com- 
mercial fertilizers are exactly alike. Commercial fertilizers are 
concentrated forms of the most necessary elements of plant food; 
sometimes this food is of good quality, and, then again, it is of 
poorer quality. 
1. Is the present use of commercial fertilizers necessary? No, not 
on an average soil. The reason for saying “no” is that the additional 
yield of the crop would not pay the cost of the fertilizer used. In 
the states which have been compelled to make use of commercial 
fertilizers, there was not originally as much plant food in the soil as 
is present in the average soil of our state; hence, our stock of plant 
food to begin with is much greater; and then, too, we can profit by 
the experience of older states. The liberal use of farm manures 
prepared so as to be strony in certain elements of plant food, will 
prove much more economical and will keep the soil in better condi- 
tion than the indiscriminate use of commercial fertilizers. 
The greatest difficulty that we will have to contend with is that of 
getting the soil out of condition by using up the organic matter too 
rapidly and then being compelled to resort to commercial fertilizers 
in order to keep up the supply of available plant food. Although 
the organic matter itself does not take any direct part in feeding 
plants, ‘ndirectly it takes a very important part. The one weak 
point about commercial fertilizers is that they furnish but little 
organic matter for the production of humus, and hence they are 
generally of only temporary benefit to the land. 
2. Will the use of commercial fertilizers produce crops of greater 
food value? Yes, but not sufficient to warrant their use for this pur- 
pose alone, It is true that the composition of a crop can be influ- 
enced by the supply of plant food, just as the composition of the 
animal body can be influenced by the food consumed; but commer- 
cial fertilizers from $25 to $40 per ton are too expensive to be consid- 
ered for this purpose. I do not wish to be understood as saying 
that we do not need to use any fertilizers, or manures, but we have 
no use at present for the expensive commercial fertilizers. If they 
can be obtained cheap enough, all right; if not, we must look to other 
and cheaper sources of plant food. 
In connection with the effects of fertilizers upon the composition 
of the crops produced, the extensive experiments of Laws and Gil- 
bert, of Rothamsted, England, are the most conclusive. Ina series 
of experiments carried on for twelve years with nine different kinds 
of manures, including those rich in nitrogen, phosphates and pot- 
ash and their various mixtures, in no case was the essential food 
products in any of the crops sufficiently improved or altered to 
warrant the use of any of the fertilizers for simply the additional 
food value of the crop produced. A complete chemical analysis was 
made of the crop from each plot for each of the twelve years. The 
experiments upon this point are particularly interesting. The re- 
sults are given in a table as follows: 
