INTRODUCTION TO NEW EDITION. XIX 



There is, as a rule, very little loss of nitrogen by drainage while 

 the wheat is growing on the ground, but after the wheat is cut, 

 the grass and clover are pretty sure to take up all the available 

 nitrogen within the range of their roots. This' summer-fallow 

 experiment, instead of affording an argument against the use 

 of summer-fallowing, is an argument in its favor. The sum- 

 mer-fallow, by exposing the soil to the decomposing influences 

 of the atmosphere, converts more or less of the inert nitro- 

 genous organic matter into ammonia and nitric acid. This is 

 precisely what a farmer wants. It is just what the wheat crop 

 needs. But we must be very careful, when we render the ni- 

 trogen soluble, to have some plant ready to take it up, and not 

 let it be washed out of the soil during the winter and early 

 spring. 



We have much poor land in the United States, and an im- 

 mense area of good land. The poor land will be used to grow 

 timber, or be improved by converting more or less of it, gradu- 

 ally, into pasture, and stocking it with sheep and cattle. The 

 main point is, to feed the sheep or cattle with some rich nitro- 

 genous food, such as cotton-seed cake, malt-sprouts, bran, 

 shorts, mill-feed, refuse beans, or bean-meal made from beans 

 injured by the weevil, or bug. In short, the owner of such 

 la:id must buy such food as will furnish the most nutriment 

 and make the richest manure at the least cost taking both of 

 these objects into consideration. He will also buy more or less 

 artificial manures, to be used for the production of fodder 

 crops, such as corn, millet, Hungarian grass, etc. And, as soon 

 as a portion of the land can be made rich enough, he will grow 

 more or less mangel wurzels, sugar beets, turnips, and other 

 root crops. Superphosphate will be found admirably adapted for 

 this purpose, and two, three, or four hundred pounds of cheap 

 potash salts, per acre, can frequently be used on fodder crops, 

 in connection with two or three hundred pounds of superphos- 

 phate, with considerable profit. The whole subject is well 

 worthy of careful study. Never in the history of the world 

 has there been a grander opportunity for the application of 

 science to the improvement of agriculture than now. 



On the richer lands, the aim of the farmer will be to convert 

 the plant food lying dormant in the soil into profitable crops. 

 The main point is good tillage. In many cases weeds now run 

 away with half our crops and all our profits. The weeds which 

 spring up after the grain crops are harvested, are not an un- 

 mixed evil. They retain the nitrogen and other plant food, and 



