28 MAN ON THE LANDSCAPE 



If this product is processed in any way the ultimate consumer may 

 have no inkling as to its true quality. Eventually this sort of 

 forcing is no longer possible. Something has to happen. Either a 

 lower grade species must be accepted, or the soil must be improved. 

 If the soil is not improved, plant quality may eventually regress to 

 the point of starving practically all animal life off the land. Man 

 must leave long before the field mice do. 



Hunger Signs in Plants. The lack of certain minerals and vita- 

 mins produce deficiencies in humans; it also affects other animals 

 likewise; and, as might be expected, plants are subject to mineral 

 deficiencies too. 



Many of these plants deficiencies may be observed easily. 6 Their 

 diagnosis may require tissue testing in some cases but the informed 

 eye can see that something is wrong. Different species of plants often 

 (but do not necessarily) exhibit the same symptoms for the same 

 disease. 



To the untrained eye tobacco plants may look pretty good. The 

 color may be a deep rich green. However a critical look will bring the 

 suspicion that a plant may be too dark a green, with the upper leaves 

 abnormally erect. To the knowing eye this means a shortage of 

 phosphorus. If the terminal bud at the top of the stalk is dead or 

 dying, boron is lacking. If calcium shortage develops, the new leaves 

 become deformed, scalloped, with irregular edges. 



Magnesium deficiency puts the chlorophyll out of action, since it 

 is part of chlorophyll. Nitrogen is also a chlorophyll part. As might 

 be expected, lack of either results in loss of greenness a yellowing. 



Lack of potassium or zinc gives a really evil, blotched, diseased 

 appearance to the leaves. 



It is not our purpose to make a plant pathologist of anyone, so 

 with a few more illustrations from the garden plants we shall move on. 

 Generally speaking most cases of uniform yellow or light green color- 

 ing, coupled with stunted growth, will indicate nitrogen lack. 



Onion bulbs may vary from a lemon color to a rich, bright coppery 

 shade according to sulphur content, yet all be reasonably well de- 

 veloped physically. 



If snap-beans produce stunted plants and no beans or pods to 

 speak of, there may be boron trouble. 



In a root crop such as turnips, beets or radishes, boron lack will 

 appear as dark spots on and in the root, ranging up to severe condi- 

 tions called brown heart or hollow heart. 



Pale yellow carrots are copper starved. 



6 The following statements are derived from Hunger Signs in Crops, published 

 by The American Society of Agronomy and The National Fertilizer Association, 

 Washington, D. C., (no date). 



