Humus Improves the Land. 221 



or applications of muck or some other organic dress- 

 ings. It is not necessary that the chemical fertil- 

 izers should be mixed before application ; in fact, 

 upon lands of varying soil and conformation, it ift 

 ordinarily better to apply the different ingredients 

 separately, because different parts of the plantation 

 may need different amounts of the various materials. 

 The low lands will ordinarily need less of the nitro- 

 gen and perhaps more of the potash and phosphoric- 

 acid. In general, it is advisable to buy the plant- 

 foods separately, as advised in the preceding pages. 

 Farmers do not appreciate the importance of 

 humus as an ameliorator of land. In farm lands, it 

 is usually supplied in form of green crops, stubble 

 or sward, and barn manures. When humus is ab- 

 sent, sandy soils become too loose and leachy and 

 hot, and clay soils bake and become lumpy. The 

 different physical characteristics of clay lumps and 

 mellow soils are largely due to the greater amount 

 of humus in the good soil, and yet we have seen 

 that the chemist may pronounce the cloddy soil 

 richer in native plant -food. If the farmer has 

 much of this hard, unproductive land, what is to 

 be done with it ? To cover it with commercial fer- 

 tilizer would be of little benefit. It must first be 

 put in fit condition for the growing of crops. A 

 crop of clover plowed under would quickly improve 

 it, but if tne land is planted to orchard he does 

 not care to seed it down. The next recourse is 

 stable manure. Of this, perhaps enough can be 

 had to cover the hardest soots. For the rest, 



