SOIL EXHAUSTION AND ROTATION IN CROPS. 85 



in poor condition" — or, "This is good soil, but it is rather 

 run down ; it is in poor condition at present." Or, looking 

 over the fields of a neighbor, who has taken a little extra 

 pains, " This is poor land, but he has got it up into good con- 

 dition." " Condition," then, is artificial or accumulated 

 strength ; a thing we cannot depend upon, except as we can 

 depend upon the continuance of the artifice or temporary 

 causes of which it is a result. " Condition " refers to those 

 elements of fertility which are oapable of being turned to ac- 

 count in the growth of crops within a limited time. We may 

 have a " condition," which is the result of natural causes, as 

 is illustrated by the manner in which Indian corn is grown in 

 some parts of South America, on land newly cleared from the 

 forest. You know that in tropical latitudes, the year is usu- 

 ally divided into two seasons — the wet and the dry. During 

 the former, abundant rains fall and vegetation grows with 

 wonderful luxuriance. The other half of the year is com- 

 paratively dry, and plant-life is inactive. At the close of the 

 rainy season, the planters chop down the timber, the brush, 

 and everything that grows upon the land where they propose 

 to get a crop. When the fallen vegetation is sufficiently dry, 

 they set it on fire, and everything burns completely except the 

 largest trees. When the fire has gone out, toward the beginning 

 of the next rainy season, they have a field destitute of vegetation 

 and coated with the ashes of the forest. There, with the small- 

 est preparation, they plant their corn in the ashes, dropping it 

 in where they can, and get a magnificent crop. Tlie second 

 year, they put on corn again and get another large crop. The 

 third year they get another crop, and after that, it is cheaper 

 to abandon that field, and to clear another. The first piece 

 grows up to forest, and in six, eight, or ten years, perhaps, 

 they can burn it over again. Here, the fertility of the soil 

 after burning is a " condition" which is produced partly by 

 natural means, the growth of the forest, which brings up 

 matters from below, and partly by artificial means, the felling 

 and burning of the forests, restoring those matters to the 

 surface. 



" Natural strength" is something which is comparatively 



