New York Agricultural Experiment Station. 85 



cate may be the methods of chemical analysis, the methods of plants 

 are still more delicate and plants are able to show differences in soil 

 where chemical analysis distinguishes none. 



Indications of Needs of Soil Afforded by Crops. — It is im- 

 possible to give any fixed rules which will cover all cases and 

 enable a farmer to tell without any experiment on his part what food 

 constituents his soil lacks. In a general way, the crops them- 

 selves may give some valuable suggestions. 



(a) As a rule, lack of nitrogen is indicated, when plants are pale- 

 green in color, or when there is a small growth of leaf or stalk, other 

 conditions being favorable. 



{IS) A bright, deep green color, with a vigorous growth of leaf 

 or stalk, is, in case of most crops, a sign that nitrogen is not lacking^ 

 but does not necessarily indicate that more nitrogen could not be 

 used to advantage. 



((') An excessive growth of leaf or stalk, accompanied by an 

 imperfect bud, flower, and fruit development, indicates too much 

 nitrogen for the potash and phosphoric acid present. 



{d) When such crops as corn, cabbage, grass, potatoes, etc., have 

 a luxuriant, healthful growth, an abundance of j)otash in the soil 

 is indicated ; also, when fleshy fruits of flne flavor and texture can 

 be successfully grown. 



{e) When a soil produces good, early maturing crops of grain, 

 with plump and hea.vy ]<.erneh, jjhosjjhoric acid will not generally 

 he found deficient in the soil. 



Such general indications may often be most helpful, and crops 

 should be studied carefully with these facts in mind. 



Experiments in Ascertaining Needs of Crops. — In order to 

 ascertain with greater certainty what food elements are lacking in 

 the soil, the surest way is for each farmer to do some experimenting 

 on his own soil and crops. Apply different kinds of fertilizing 

 materials in different combinations, using for example, potash com- 

 pounds alone in one place, phosphoric acid compounds in another, 

 nitrogenous materials in another. Then different combinations can 

 be made on other portions of the crop. Some portions of the field can 

 be left without application of any kilKi. The results can then be 

 studied in the yield of crop. It is generally found that the appli- 

 cation of phosphoric acid gives excellent results on fields which 

 have long been cropped with grain without keeping up the supply 

 of plant-food. In other places, it is found that best results are 



