Fertilizers For Grapes

As regards fertilizers, the grape-grower has much to learn and in

learning he must approach the problem with humility of mind. For in

his experimenting, which is the best way to learn, he will no sooner

arrive at what seems to be a certain conclusion, than another season's

results or the yields in an adjoining vineyard will upset the findings

of past seasons and those obtained in other places. Unfortunately,

there is l ttle real knowledge to be obtained on the subject, for

grape-growers have not yet broken away from time-worn dictums in

regard to fertilizers and still follow recommendations drawn from work

with truck and field crops. This is excused by the fact that there

have been almost no comprehensive experiments in the country with

fertilizers for grapes.



No fallacies die harder than the pronouncements of chemists a

generation ago that fertilizing consists in putting in the soil

approximately that which the plants take out; and that the chemical

composition of the crop affords the necessary guide to fertilizing.

These two theories are the basis of nearly every recommendation that

can be found for the use of fertilizers in growing crops. The facts

applied to the grape, however, are that the average tillable soil

contains a hundred or a thousand times more of the chemical

constituents of plants than the grape can possibly take from the soil;

and many experiments in supplying food to plants show that the

chemical composition of the plant is not a safe guide to their

fertilizer requirements. Later teachings in regard to the use of

fertilizers are: That the quantity of mineral food in a soil may be of

far less importance than the quantity of water, and that the

cultivator should make certain that there is sufficient moisture in

his land so that the mineral salts may be readily dissolved and so

become available as plant-food; that far too much importance has been

attached to putting chemicals in the soil and too little to the

physical condition of the soil, whereby the work of bacteria and the

solvent action of organic acids may make available plant-food that

without these agencies is unavailable.



These brief and simple statements introduce to grape-growers some of

the problems with which they must deal in fertilizing grapes, and show

what a complex problem of chemistry, physics and biology fertilizing

the soil is; how difficult experimental work in this field is; and how

cautious workers must be in interpreting results of either experiment

or experience. An account of an experiment in fertilizing a vineyard

may make even more plain the difficulties in carrying on experiments

in fertilizing fruits and the caution that must be observed in drawing

conclusions.