FLORIDA STATE HORTICULTURAL SOCIETY. 
83 
ance on published formulas which have 
been made up from the analysis of the 
soil and the crop, and have contented our¬ 
selves with these data. The subject of 
animal nutrition and feeding is naturally 
one of considerable complication and dif¬ 
ficulty, as compared with plant feeding, 
but I think that we shall eventually come 
to believe that the more intimate ques¬ 
tions of plant nutrition, approach it in 
this respect. To be sure we are concern¬ 
ed in furnishing only a very small 
percent of the total plant food that is re¬ 
quired, as by far the larger part is ob¬ 
tained from the air, but that part is just 
as essential to the growth of the plant as 
the other. If the problem was merely 
one of determining just how much pot¬ 
ash, phosphoric acid and nitrogen was re¬ 
moved in the crop and was required for 
the additional growth for the year, it 
would be easily solved. But in practice, 
this is found to be wholly inadequate for 
crops like the orange and from eight to 
ten times as much as the amount so indi¬ 
cated by the above figures seem to be re¬ 
quired to keep the plant up to the best 
condition of quality and quantity of fruit. 
Where does this excess go to, and how 
can we economize by reducing this dis¬ 
crepancy to a minimum without lower¬ 
ing the results we wish to obtain?. To 
answer this question, I think we must 
turn from the chemical side of the ques¬ 
tion to the physical one, or. in other 
words, study the physical and mechani¬ 
cal conditions of our soils to find a solu¬ 
tion. 
There are various sources of loss of 
plant food in the soil, and reasons why 
the plant does not get all that we apply, 
with which we are acquainted. One of 
the most evident of these is the leaching 
of the material through the soil and car¬ 
rying it away from the area of the root 
system of the plant. The rapidity of this 
leaching increases markedly as we pass 
from a clay to a sandy soil. Now, on 
our Florida soils there is no question but 
that leaching goes on to a very great ex¬ 
tent. It is of course desirable that we 
have our plant food in a soluble form as 
it is only in this condition that the plants 
can make use of it. If we apply it in 
this condition, or in such compounds that 
it rapidly becomes so, it is conceivable 
and no doubt to a large extent true, that 
with the first soaking of the soil with rain 
it is carried away to a large extent be¬ 
yond the reach of the plant (speaking 
particularly of our loose, sandy Florida 
soils.). Now can we prevent this serious 
and expensive loss ? At present the meth¬ 
od of overcoming this seems to be to sup¬ 
ply sufficient to allow for this loss and to 
feed the plant too, which is one reason 
why we have 'to apply from eight to ten 
times the amount removed by the crop, and 
that would seem, from all rational and 
scientific standpoints, to be necessary. In 
other words, we apply say from one to 
two tons to the acre, expecting and know¬ 
ing that we shall lose a large part of it, 
when perhaps 200 to 300 pounds is all 
the crop needs and makes use of. If such 
conditions held in any technical line, you 
may be sure the manufacturer would 
take immediate steps to prevent this loss. 
If the farmer can stand this constant 
drain and still make a profit, there must 
indeed be money in farming. I believe, 
however, that we can control this loss to 
a considerable extent. According to the 
usual practice, we make one or two appli¬ 
cations of fertilizers a year to the 
crop and expect it to save and make use 
